Trileptal® (oxcarbazepine) is an antiepileptic drug available as 150 mg, 300 mg and 600 mg film-coated tablets for oral administration. Trileptal is also available as a 300 mg/5 mL (60 mg/mL) oral suspension. Oxcarbazepine is 10,11-Dihydro-10-oxo-5H-dibenz[b,f]azepine- 5-carboxamide, and its structural formula is

Oxcarbazepine is a white to faintly orange crystalline powder. It is slightly soluble in chloroform, dichloromethane, acetone, and methanol and practically insoluble in ethanol, ether and water. Its molecular weight is 252.27.

Trileptal film-coated tablets contain the following inactive ingredients: colloidal silicon dioxide, crospovidone, hydroxypropyl methylcellulose, iron oxide, magnesium stearate, microcrystalline cellulose, polyethylene glycol, talc and titanium dioxide.

Trileptal oral suspension contains the following inactive ingredients: ascorbic acid; dispersible cellulose; ethanol; macrogol stearate; methyl parahydroxybenzoate; propylene glycol; propyl parahydroxybenzoate; purified water; sodium saccharin; sorbic acid; sorbitol; yellow-plum-lemon aroma.

Last updated on RxList: 4/8/2008

Trileptal® (oxcarbazepine) is indicated for use as monotherapy or adjunctive therapy in the treatment of partial seizures in adults and as monotherapy in the treatment of partial seizures in children aged 4 years and above with epilepsy, and as adjunctive therapy in children aged 2 years and above with epilepsy.

Trileptal® (oxcarbazepine) is recommended as adjunctive treatment in the treatment of partial seizures in adults and children aged 2-16 years. Trileptal is also recommended as monotherapy in the treatment of partial seizures in adults and children aged 4-16 years. All dosing should be given in a twice-a-day (BID) regimen. Trileptal oral suspension and Trileptal film-coated tablets may be interchanged at equal doses.

Trileptal should be kept out of the reach and sight of children.

Before using Trileptal oral suspension, shake the bottle well and prepare the dose immediately afterwards. The prescribed amount of oral suspension should be withdrawn from the bottle using the oral dosing syringe supplied. Trileptal oral suspension can be mixed in a small glass of water just prior to administration or, alternatively, may be swallowed directly from the syringe. After each use, close the bottle and rinse the syringe with warm water and allow it to dry thoroughly.

Trileptal can be taken with or without food (see CLINICAL PHARMACOLOGY, Pharmacokinetics subsection).

Adults

Adjunctive Therapy

Treatment with Trileptal should be initiated with a dose of 600 mg/day, given in a BID regimen. If clinically indicated, the dose may be increased by a maximum of 600 mg/day at approximately weekly intervals; the recommended daily dose is 1200 mg/day. Daily doses above 1200 mg/day show somewhat greater effectiveness in controlled trials, but most patients were not able to tolerate the 2400 mg/day dose, primarily because of CNS effects. It is recommended that the patient be observed closely and plasma levels of the concomitant AEDs be monitored during the period of Trileptal titration, as these plasma levels may be altered, especially at Trileptal doses greater than 1200 mg/day (see PRECAUTIONS: DRUG INTERACTIONS subsection).

Conversion to Monotherapy

Patients receiving concomitant AEDs may be converted to monotherapy by initiating treatment with Trileptal at 600 mg/day (given in a BID regimen) while simultaneously initiating the reduction of the dose of the concomitant AEDs. The concomitant AEDs should be completely withdrawn over 3-6 weeks, while the maximum dose of Trileptal should be reached in about 2-4 weeks. Trileptal may be increased as clinically indicated by a maximum increment of 600 mg/day at approximately weekly intervals to achieve the recommended daily dose of 2400 mg/day. A daily dose of 1200 mg/day has been shown in one study to be effective in patients in whom monotherapy has been initiated with Trileptal. Patients should be observed closely during this transition phase.

Initiation of Monotherapy

Patients not currently being treated with AEDs may have monotherapy initiated with Trileptal. In these patients, Trileptal should be initiated at a dose of 600 mg/day (given in a BID regimen); the dose should be increased by 300 mg/day every third day to a dose of 1200 mg/day. Controlled trials in these patients examined the effectiveness of a 1200 mg/day dose; a dose of 2400 mg/day has been shown to be effective in patients converted from other AEDs to Trileptal monotherapy (see above).

Pediatric Patients

Adjunctive Therapy (Aged 2-16 Years)

In pediatric patients aged 4-16 years, treatment should be initiated at a daily dose of 8-10 mg/kg generally not to exceed 600 mg/day, given in a BID regimen. The target maintenance dose of Trileptal should be achieved over two weeks, and is dependent upon patient weight, according to the following chart:

20-29 kg - 900 mg/day

29.1-39 kg - 1200 mg/day

> 39 kg - 1800 mg/day

In the clinical trial, in which the intention was to reach these target doses, the median daily dose was 31 mg/kg with a range of 6-51 mg/kg.

In pediatric patients aged 2- < 4 years, treatment should also be initiated at a daily dose of 8-10 mg/kg generally not to exceed 600 mg/day, given in a BID regimen. For patients under 20 kg, a starting dose of 16-20 mg/kg may be considered (see CLINICAL PHARMACOLOGY). The maximum maintenance dose of Trileptal should be achieved over 2-4 weeks and should not exceed 60 mg/kg/day in a BID regimen.

In the clinical trial in pediatric patients (2 to 4 years of age) in which the intention was to reach the target dose of 60 mg/kg/day, 50% of patients reached a final dose of at least 55 mg/kg/day.

Under adjunctive therapy (with and without enzyme-inducing AEDs), when normalized by body weight, apparent clearance (L/hr/kg) decreased when age increased such that children 2 to < 4 years of age may require up to twice the oxcarbazepine dose per body weight compared to adults; and children 4 to ≤ 12 years of age may require a 50% higher oxcarbazepine dose per body weight compared to adults.

Conversion to Monotherapy (Aged 4-16 Years)

Patients receiving concomitant antiepileptic drugs may be converted to monotherapy by initiating treatment with Trileptal at approximately 8-10 mg/kg/day given in a BID regimen, while simultaneously initiating the reduction of the dose of the concomitant antiepileptic drugs. The concomitant antiepileptic drugs can be completely withdrawn over 3-6 weeks while Trileptal may be increased as clinically indicated by a maximum increment of 10 mg/kg/day at approximately weekly intervals to achieve the recommended daily dose. Patients should be observed closely during this transition phase.

The recommended total daily dose of Trileptal is shown in the table below.

Initiation of Monotherapy (Aged 4-16 Years)

Patients not currently being treated with antiepileptic drugs may have monotherapy initiated with Trileptal. In these patients, Trileptal should be initiated at a dose of 8-10 mg/kg/day given in a BID regimen. The dose should be increased by 5 mg/kg/day every third day to the recommended daily dose shown in the table below.

Table 7: Range of Maintenance Doses of Trileptal® for Children by Weight During Monotherapy

	From	To
Weight in kg	Dose (mg/day)	Dose (mg/day)
20	600	900
25	900	1200
30	900	1200
35	900	1500
40	900	1500
45	1200	1500
50	1200	1800
55	1200	1800
60	1200	2100
65	1200	2100
70	1500	2100

Patients with Hepatic Impairment

In general, dose adjustments are not required in patients with mild-to-moderate hepatic impairment (see CLINICAL PHARMACOLOGY, Pharmacokinetics, Special Populations subsection).

Patients with Renal Impairment

In patients with impaired renal function (creatinine clearance < 30 mL/min) Trileptal therapy should be initiated at one-half the usual starting dose (300 mg/day) and increased slowly to achieve the desired clinical response (see CLINICAL PHARMACOLOGY, Pharmacokinetics, Special Populations subsection).

Tablets

150 mg Film-Coated Tablets: pale grey-green, ovaloid, slightly biconvex, scored on both sides. Imprinted with T/D on one side and C/G on the other side.

Bottle of 100...................................NDC 0078-0456-05 Unit Dose (blister pack)
Box of 100 (strips of 10)...................................NDC 0078-0456-35

300 mg Film-Coated Tablets: yellow, ovaloid, slightly biconvex, scored on both sides. Imprinted with TE/TE on one side and CG/CG on the other side.

Bottle of 100...................................NDC 0078-0337-05 Unit Dose (blister pack)
Box of 100 (strips of 10)...................................NDC 0078-0337-06

600 mg Film-Coated Tablets: light pink, ovaloid, slightly biconvex, scored on both sides. Imprinted with TF/TF on one side and CG/CG on the other side.

Bottle of 100...................................NDC 0078-0457-05 Unit Dose (blister pack)
Box of 100 (strips of 10)...................................NDC 0078-0457-35

Store at 25°C (77°F); excursions permitted to 15-30°C (59-86°F) [see USP Controlled Room Temperature]. Dispense in tight container (USP).

Suspension

300 mg/5 mL (60 mg/mL) Oral Suspension: off-white to slightly brown or slightly red suspension. Available in amber glass bottles containing 250 mL of oral suspension. Supplied with a 10 mL dosing syringe and press-in bottle adapter.

Bottle containing 250 mL of oral suspension............................NDC 0078-0357-52

Store Trileptal® (oxcarbazepine) oral suspension in the original container. Shake well before using.

Use within 7 weeks of first opening the bottle.

Store at 25°C (77°F); excursions permitted to 15-30°C (59-86°F) [see USP Controlled Room Temperature].

REV: AUGUST 2007. Novartis Pharmaceuticals Corporation, East Hanover, New Jersey 07936. FDA Rev date: 8/31/2007

Last updated on RxList: 4/8/2008

Most Common Adverse Events in All Clinical Studies

Adjunctive Therapy/Monotherapy in Adults Previously Treated with other AEDs: The most commonly observed ( ≥ 5%) adverse experiences seen in association with Trileptal® (oxcarbazepine) and substantially more frequent than in placebo-treated patients were: Dizziness, somnolence, diplopia, fatigue, nausea, vomiting, ataxia, abnormal vision, abdominal pain, tremor, dyspepsia, abnormal gait.

Approximately 23% of these 1,537 adult patients discontinued treatment because of an adverse experience. The adverse experiences most commonly associated with discontinuation were: Dizziness (6.4%), diplopia (5.9%), ataxia (5.2%), vomiting (5.1%), nausea (4.9%), somnolence (3.8%), headache (2.9%), fatigue (2.1%), abnormal vision (2.1%), tremor (1.8%), abnormal gait (1.7%), rash (1.4%), hyponatremia (1.0%).

Monotherapy in Adults Not Previously Treated with other AEDs: The most commonly observed ( ≥ 5%) adverse experiences seen in association with Trileptal in these patients were similar to those in previously treated patients.

Approximately 9% of these 295 adult patients discontinued treatment because of an adverse experience. The adverse experiences most commonly associated with discontinuation were: Dizziness (1.7%), nausea (1.7%), rash (1.7%), headache (1.4%).

Adjunctive Therapy/Monotherapy in Pediatric Patients 4 Years Old and Above Previously Treated with other AEDs: The most commonly observed ( ≥ 5%) adverse experiences seen in association with Trileptal in these patients were similar to those seen in adults.

Approximately 11% of these 456 pediatric patients discontinued treatment because of an adverse experience. The adverse experiences most commonly associated with discontinuation were: Somnolence (2.4%), vomiting (2.0%), ataxia (1.8%), diplopia (1.3%), dizziness (1.3%), fatigue (1.1%), nystagmus (1.1%).

Monotherapy in Pediatric Patients 4 Years Old and Above Not Previously Treated with other AEDs: The most commonly observed ( ≥ 5%) adverse experiences seen in association with Trileptal in these patients were similar to those in adults.

Approximately 9.2% of 152 pediatric patients discontinued treatment because of an adverse experience. The adverse experiences most commonly associated ( ≥ 1%) with discontinuation were rash (5.3%) and maculopapular rash (1.3%).

Adjunctive Therapy/Monotherapy in Pediatric Patients 1 Month to < 4 Years Old Previously Treated or Not Previously Treated with other AEDs: The most commonly observed ( ≥ 5%) adverse experiences seen in association with Trileptal in these patients were similar to those seen in older children and adults except for infections and infestations which were more frequently seen in these younger children.

Approximately 11% of these 241 pediatric patients discontinued treatment because of an adverse experience. The adverse experiences most commonly associated with discontinuation were: Convulsions (3.7%), status epilepticus (1.2%), and ataxia (1.2%).

Incidence in Controlled Clinical Studies: The prescriber should be aware that the figures in Tables 3, 4, 5 and 6 cannot be used to predict the frequency of adverse experiences in the course of usual medical practice where patient characteristics and other factors may differ from those prevailing during clinical studies. Similarly, the cited frequencies cannot be directly compared with figures obtained from other clinical investigations involving different treatments, uses, or investigators. An inspection of these frequencies, however, does provide the prescriber with one basis to estimate the relative contribution of drug and nondrug factors to the adverse event incidences in the population studied.

Controlled Clinical Studies of Adjunctive Therapy/Monotherapy in Adults Previously Treated with other AEDs: Table 3 lists treatment-emergent signs and symptoms that occurred in at least 2% of adult patients with epilepsy treated with Trileptal or placebo as adjunctive treatment and were numerically more common in the patients treated with any dose of Trileptal. Table 4 lists treatment-emergent signs and symptoms in patients converted from other AEDs to either high dose Trileptal or low dose (300 mg) Trileptal. Note that in some of these monotherapy studies patients who dropped out during a preliminary tolerability phase are not included in the tables.

Table 3: Treatment-Emergent Adverse Event Incidence in a Controlled Clinical Study of Adjunctive Therapy in Adults (Events in at Least 2% of Patients Treated with 2400 mg/day of Trileptal® and Numerically More Frequent Than in the Placebo Group)

Body System/ Adverse Event	Oxcarbazepine Dosage (mg/day)
	OXC 600 N=163 %	OXC 1200 N=171 %	OXC 2400 N=126 %	Placebo N=166 %
Body as a Whole
Fatigue	15	12	15	7
Asthenia	6	3	6	5
Edema Legs	2	1	2	1
Weight Increase	1	2	2	1
Feeling Abnormal	0	1	2	0
Cardiovascular System
Hypotension	0	1	2	0
Digestive System
Nausea	15	25	29	10
Vomiting	13	25	36	5
Pain Abdominal	10	13	11	5
Diarrhea	5	6	7	6
Dyspepsia	5	5	6	2
Constipation	2	2	6	4
Gastritis	2	1	2	1
Metabolic and Nutritional Disorders
Hyponatremia	3	1	2	1
Musculoskeletal System
Muscle Weakness	1	2	2	0
Sprains and Strains	0	2	2	1
Nervous System
Headache	32	28	26	23
Dizziness	26	32	49	13
Somnolence	20	28	36	12
Ataxia	9	17	31	5
Nystagmus	7	20	26	5
Gait Abnormal	5	10	17	1
Insomnia	4	2	3	1
Tremor	3	8	16	5
Nervousness	2	4	2	1
Agitation	1	1	2	1
Coordination Abnormal	1	3	2	1
EEG Abnormal	0	0	2	0
Speech Disorder	1	1	3	0
Confusion	1	1	2	1
Cranial Injury NOS	1	0	2	1
Dysmetria	1	2	3	0
Thinking Abnormal	0	2	4	0
Respiratory System
Rhinitis	2	4	5	4
Skin and Appendages
Acne	1	2	2	0
Special Senses
Diplopia	14	30	40	5
Vertigo	6	12	15	2
Vision Abnormal	6	14	13	4
Accommodation Abnormal	0	0	2	0

Table 4: Treatment-Emergent Adverse Event Incidence in Controlled Clinical Studies of Monotherapy in Adults Previously Treated with Other AEDs (Events in at Least 2% of Patients Treated with 2400 mg/day of Trileptal® and Numerically More Frequent Than in the Low Dose Control Group)

	Oxcarbazepine Dosage (mg/day)
Body System/ Adverse Event	2400 N=86 %	300 N=86 %
Body as a Whole
Fatigue	21	5
Fever	3	0
Allergy	2	0
Edema Generalized	2	1
Pain Chest	2	0
Digestive System
Nausea	22	7
Vomiting	15	5
Diarrhea	7	5
Dyspepsia	6	1
Anorexia	5	3
Pain Abdominal	5	3
Mouth Dry	3	0
Hemorrhage Rectum	2	0
Toothache	2	1
Hemic and Lymphatic System
Lymphadenopathy	2	0
Infections and Infestations
Infection Viral	7	5
Infection	2	0
Metabolic and Nutritional Disorders
Hyponatremia	5	0
Thirst	2	0
Nervous System
Headache	31	15
Dizziness	28	8
Somnolence	19	5
Anxiety	7	5
Ataxia	7	1
Confusion	7	0
Nervousness	7	0
Insomnia	6	3
Tremor	6	3
Amnesia	5	1
Convulsions Aggravated	5	2
Emotional Lability	3	2
Hypoesthesia	3	1
Coordination Abnormal	2	1
Nystagmus	2	0
Speech Disorder	2	0
Respiratory System
Upper Respiratory Tract Infection	10	5
Coughing	5	0
Bronchitis	3	0
Pharyngitis	3	0
Skin and Appendages
Hot Flushes	2	1
Purpura	2	0
Special Senses
Vision Abnormal	14	2
Diplopia	12	1
Taste Perversion	5	0
Vertigo	3	0
Earache	2	1
Ear Infection NOS	2	0
Urogenital and Reproductive System
Urinary Tract Infection	5	1
Micturition Frequency	2	1
Vaginitis	2	0

Controlled Clinical Study of Monotherapy in Adults Not Previously Treated with other AEDs: Table 5 lists treatment-emergent signs and symptoms in a controlled clinical study of monotherapy in adults not previously treated with other AEDs that occurred in at least 2% of adult patients with epilepsy treated with Trileptal or placebo and were numerically more common in the patients treated with Trileptal.

Table 5: Treatment-Emergent Adverse Event Incidence in a Controlled Clinical Study of Monotherapy in Adults Not Previously Treated with Other AEDs (Events in at Least 2% of Patients Treated with Trileptal® and Numerically More Frequent Than in the Placebo Group)

Body System/ Adverse Event	Oxcarbazepine N=55 %	Placebo N=49 %
Body as a Whole
Falling Down NOS	4	0
Digestive System
Nausea	16	12
Diarrhea	7	2
Vomiting	7	6
Constipation	5	0
Dyspepsia	5	4
Musculoskeletal System
Pain Back	4	2
Nervous System
Dizziness	22	6
Headache	13	10
Ataxia	5	0
Nervousness	5	2
Amnesia	4	2
Coordination Abnormal	4	2
Tremor	4	0
Respiratory System
Upper Respiratory Tract Infection	7	0
Epistaxis	4	0
Infection Chest	4	0
Sinusitis	4	2
Skin and Appendages
Rash	4	2
Special Senses
Vision Abnormal	4	0

Controlled Clinical Studies of Adjunctive Therapy/Monotherapy in Pediatric Patients Previously Treated with other AEDs: Table 6 lists treatment-emergent signs and symptoms that occurred in at least 2% of pediatric patients with epilepsy treated with Trileptal or placebo as adjunctive treatment and were numerically more common in the patients treated with Trileptal.

Table 6: Treatment-Emergent Adverse Event Incidence in Controlled Clinical Studies of Adjunctive Therapy/Monotherapy in Pediatric Patients Previously Treated with Other AEDs (Events in at Least 2% of Patients Treated with Trileptal® and Numerically More Frequent Than in the Placebo Group)

Body System/ Adverse Event	Oxcarbazepine N=171 %	Placebo N=139 %
Body as a Whole
Fatigue	13	9
Allergy	2	0
Asthenia	2	1
Digestive System
Vomiting	33	14
Nausea	19	5
Constipation	4	1
Dyspepsia	2	0
Nervous System
Headache	31	19
Somnolence	31	13
Dizziness	28	8
Ataxia	13	4
Nystagmus	9	1
Emotional Lability	8	4
Gait Abnormal	8	3
Tremor	6	4
Speech Disorder	3	1
Concentration Impaired	2	1
Convulsions	2	1
Muscle Contractions Involuntary	2	1
Respiratory System
Rhinitis	10	9
Pneumonia	2	1
Skin and Appendages
Bruising	4	2
Sweating Increased	3	0
Special Senses
Diplopia	17	1
Vision Abnormal	13	1
Vertigo	2	0

Other Events Observed in Association with the Administration of Trileptal

In the paragraphs that follow, the adverse events, other than those in the preceding tables or text, that occurred in a total of 565 children and 1,574 adults exposed to Trileptal and that are reasonably likely to be related to drug use are presented. Events common in the population, events reflecting chronic illness and events likely to reflect concomitant illness are omitted particularly if minor. They are listed in order of decreasing frequency. Because the reports cite events observed in open label and uncontrolled trials, the role of Trileptal in their causation cannot be reliably determined.

Body as a Whole: Fever, malaise, pain chest precordial, rigors, weight decrease.

Cardiovascular System: Bradycardia, cardiac failure, cerebral hemorrhage, hypertension, hypotension postural, palpitation, syncope, tachycardia.

Digestive System: Appetite increased, blood in stool, cholelithiasis, colitis, duodenal ulcer, dysphagia, enteritis, eructation, esophagitis, flatulence, gastric ulcer, gingival bleeding, gum hyperplasia, hematemesis, hemorrhage rectum, hemorrhoids, hiccup, mouth dry, pain biliary, pain right hypochondrium, retching, sialoadenitis, stomatitis, stomatitis ulcerative.

Hemic and Lymphatic System: Leukopenia, thrombocytopenia.

Laboratory Abnormality: Gamma-GT increased, hyperglycemia, hypocalcemia, hypoglycemia, hypokalemia, liver enzymes elevated, serum transaminase increased.

Musculoskeletal System: Hypertonia muscle.

Nervous System: Aggressive reaction, amnesia, anguish, anxiety, apathy, aphasia, aura, convulsions aggravated, delirium, delusion, depressed level of consciousness, dysphonia, dystonia, emotional lability, euphoria, extrapyramidal disorder, feeling drunk, hemiplegia, hyperkinesia, hyperreflexia, hypoesthesia, hypokinesia, hyporeflexia, hypotonia, hysteria, libido decreased, libido increased, manic reaction, migraine, muscle contractions involuntary, nervousness, neuralgia, oculogyric crisis, panic disorder, paralysis, paroniria, personality disorder, psychosis, ptosis, stupor, tetany.

Respiratory System: Asthma, dyspnea, epistaxis, laryngismus, pleurisy.

Skin and Appendages: Acne, alopecia, angioedema, bruising, dermatitis contact, eczema, facial rash, flushing, folliculitis, heat rash, hot flushes, photosensitivity reaction, pruritus genital, psoriasis, purpura, rash erythematous, rash maculopapular, vitiligo, urticaria.

Special Senses: Accommodation abnormal, cataract, conjunctival hemorrhage, edema eye, hemianopia, mydriasis, otitis externa, photophobia, scotoma, taste perversion, tinnitus, xerophthalmia.

Surgical and Medical Procedures: Procedure dental oral, procedure female reproductive, procedure musculoskeletal, procedure skin.

Urogenital and Reproductive System: Dysuria, hematuria, intermenstrual bleeding, leukorrhea, menorrhagia, micturition frequency, pain renal, pain urinary tract, polyuria, priapism, renal calculus.

Other: Systemic lupus erythematosus.

Post-Marketing and Other Experience

The following adverse events not seen in controlled clinical trials have been observed in named patient programs or post-marketing experience:

Body as a Whole: Multi-organ hypersensitivity disorders characterized by features such as rash, fever, lymphadenopathy, abnormal liver function tests, eosinophilia and arthralgia (see PRECAUTIONS, Multi-Organ Hypersensitivity subsection).

Anaphylaxis (see WARNINGS, Anaphylactic Reactions and Angioedema subsection).

Digestive System: Pancreatitis and/or lipase and/or amylase increase.

Hemic and Lymphatic System: Bone marrow depression, agranulocytosis, aplastic anemia, pancytopenia, neutropenia (see PRECAUTIONS, Hematologic Events subsection).

Metabolism and Nutrition Disorders: Folic acid deficiency.

Skin and Appendages: Erythema multiforme, Stevens-Johnson syndrome, toxic epidermal necrolysis (see WARNINGS, Serious Dermatological Reactions subsection).

Drug Abuse And Dependence

Abuse

The abuse potential of Trileptal® (oxcarbazepine) has not been evaluated in human studies.

Dependence

Intragastric injections of oxcarbazepine to four cynomolgus monkeys demonstrated no signs of physical dependence as measured by the desire to self-administer oxcarbazepine by lever pressing activity.

Oxcarbazepine can inhibit CYP2C19 and induce CYP3A4/5 with potentially important effects on plasma concentrations of other drugs. In addition, several AEDs that are cytochrome P450 inducers can decrease plasma concentrations of oxcarbazepine and MHD.

Oxcarbazepine was evaluated in human liver microsomes to determine its capacity to inhibit the major cytochrome P450 enzymes responsible for the metabolism of other drugs. Results demonstrate that oxcarbazepine and its pharmacologically active 10-monohydroxy metabolite (MHD) have little or no capacity to function as inhibitors for most of the human cytochrome P450 enzymes evaluated (CYP1A2, CYP2A6, CYP2C9, CYP2D6, CYP2E1, CYP4A9 and CYP4A11) with the exception of CYP2C19 and CYP3A4/5. Although inhibition of CYP3A4/5 by oxcarbazepine and MHD did occur at high concentrations, it is not likely to be of clinical significance. The inhibition of CYP2C19 by oxcarbazepine and MHD, however, is clinically relevant (see below).

In vitro, the UDP-glucuronyl transferase level was increased, indicating induction of this enzyme. Increases of 22% with MHD and 47% with oxcarbazepine were observed. As MHD, the predominant plasma substrate, is only a weak inducer of UDP-glucuronyl transferase, it is unlikely to have an effect on drugs that are mainly eliminated by conjugation through UDP-glucuronyl transferase (e.g., valproic acid, lamotrigine).

In addition, oxcarbazepine and MHD induce a subgroup of the cytochrome P450 3A family (CYP3A4 and CYP3A5) responsible for the metabolism of dihydropyridine calcium antagonists, oral contraceptives and cyclosporine resulting in a lower plasma concentration of these drugs.

As binding of MHD to plasma proteins is low (40%), clinically significant interactions with other drugs through competition for protein binding sites are unlikely.

Antiepileptic Drugs

Potential interactions between Trileptal and other AEDs were assessed in clinical studies. The effect of these interactions on mean AUCs and Cmin are summarized in Table 2.

Table 2: Summary of AED Interactions with Trileptal®

AED Coadministered	Dose of AED (mg/day)	Trileptal Dose (mg/day)	Influence of Trileptal on AED Concentration (Mean Change, 90% confidence Interval)	Influence of AED on MHD Concentration (Mean Change, 90% Confidence Interval)
Carbamazepine	400-2000	900	nc1	40% decrease [CI: 17% decrease, 57% decrease]
Phenobarbital	100-150	600-1800	14% increase [CI: 2% increase, 24% increase]	25% decrease [CI: 12% decrease, 51% decrease]
Phenytoin	250-500	600-1800 > 1200-2400	nc1,2 up to 40%increase3 [CI: 12% increase, 60% increase]	30% decrease [CI: 3% decrease, 48% decrease]
Valproic acid	400-2800	600-1800	nc1	18% decrease [CI: 13% decrease, 40% decrease]
1 nc denotes a mean change of less than 10% 2 Pediatrics 3 Mean increase in adults at high Trileptal doses

In vivo, the plasma levels of phenytoin increased by up to 40% when Trileptal was given at doses above 1200 mg/day. Therefore, when using doses of Trileptal greater than 1200 mg/day during adjunctive therapy, a decrease in the dose of phenytoin may be required. The increase of phenobarbital level, however, is small (15%) when given with Trileptal.

Strong inducers of cytochrome P450 enzymes (i.e., carbamazepine, phenytoin and phenobarbital) have been shown to decrease the plasma levels of MHD (29%-40%).

No autoinduction has been observed with Trileptal.

Hormonal Contraceptives

Coadministration of Trileptal with an oral contraceptive has been shown to influence the plasma concentrations of the two hormonal components, ethinylestradiol (EE) and levonorgestrel (LNG). The mean AUC values of EE were decreased by 48% [90% CI: 22-65] in one study and 52% [90% CI: 38-52] in another study. The mean AUC values of LNG were decreased by 32% [90% CI: 20-45] in one study and 52% [90% CI: 42-52] in another study. Therefore, concurrent use of Trileptal with hormonal contraceptives may render these contraceptives less effective (see DRUG INTERACTIONS subsection). Studies with other oral or implant contraceptives have not been conducted.

Calcium Antagonists

After repeated coadministration of Trileptal, the AUC of felodipine was lowered by 28% [90% CI: 20-33].

Verapamil produced a decrease of 20% [90% CI: 18-27] of the plasma levels of MHD.

Other Drug Interactions

Cimetidine, erythromycin and dextropropoxyphene had no effect on the pharmacokinetics of MHD. Results with warfarin show no evidence of interaction with either single or repeated doses of Trileptal.

Drug/Laboratory Test Interactions

There are no known interactions of Trileptal with commonly used laboratory tests.

Last updated on RxList: 4/8/2008

Hyponatremia

Clinically significant hyponatremia (sodium < 125 mmol/L) can develop during Trileptal® (oxcarbazepine) use. In the 14 controlled epilepsy studies 2.5% of Trileptal-treated patients (38/1,524) had a sodium of less than 125 mmol/L at some point during treatment, compared to no such patients assigned placebo or active control (carbamazepine and phenobarbital for adjunctive and monotherapy substitution studies, and phenytoin and valproate for the monotherapy initiation studies). Clinically significant hyponatremia generally occurred during the first three months of treatment with Trileptal, although there were patients who first developed a serum sodium < 125 mmol/L more than one year after initiation of therapy. Most patients who developed hyponatremia were asymptomatic but patients in the clinical trials were frequently monitored and some had their Trileptal dose reduced, discontinued, or had their fluid intake restricted for hyponatremia. Whether or not these maneuvers prevented the occurrence of more severe events is unknown. Cases of symptomatic hyponatremia have been reported during post-marketing use. In clinical trials, patients whose treatment with Trileptal was discontinued due to hyponatremia generally experienced normalization of serum sodium within a few days without additional treatment.

Measurement of serum sodium levels should be considered for patients during maintenance treatment with Trileptal, particularly if the patient is receiving other medications known to decrease serum sodium levels (for example, drugs associated with inappropriate ADH secretion) or if symptoms possibly indicating hyponatremia develop (e.g., nausea, malaise, headache, lethargy, confusion, obtundation, or increase in seizure frequency or severity).

Anaphylactic Reactions and Angioedema

Rare cases of anaphylaxis and angioedema involving the larynx, glottis, lips and eyelids have been reported in patients after taking the first or subsequent doses of Trileptal. Angioedema associated with laryngeal edema can be fatal. If a patient develops any of these reactions after treatment with Trileptal, the drug should be discontinued and an alternative treatment started. These patients should not be rechallenged with the drug (see WARNINGS, Patients with a Past History of Hypersensitivity Reaction to Carbamazepine subsection).

Patients with a Past History of Hypersensitivity Reaction to Carbamazepine

Patients who have had hypersensitivity reactions to carbamazepine should be informed that approximately 25%-30% of them will experience hypersensitivity reactions with Trileptal. For this reason patients should be specifically questioned about any prior experience with carbamazepine, and patients with a history of hypersensitivity reactions to carbamazepine should ordinarily be treated with Trileptal only if the potential benefit justifies the potential risk. If signs or symptoms of hypersensitivity develop, Trileptal should be discontinued immediately (see WARNINGS, Anaphylactic Reactions and Angioedema subsection; see PRECAUTIONS, Multi-Organ Hypersensitivity subsection).

Serious Dermatological Reactions

Serious dermatological reactions, including Stevens-Johnson syndrome (SJS) and toxic epidermal necrolysis (TEN), have been reported in both children and adults in association with Trileptal use. The median time of onset for reported cases was 19 days. Such serious skin reactions may be life threatening, and some patients have required hospitalization with very rare reports of fatal outcome. Recurrence of the serious skin reactions following rechallenge with Trileptal has also been reported.

The reporting rate of TEN and SJS associated with Trileptal use, which is generally accepted to be an underestimate due to underreporting, exceeds the background incidence rate estimates by a factor of 3- to 10-fold. Estimates of the background incidence rate for these serious skin reactions in the general population range between 0.5 to 6 cases per million- person years. Therefore, if a patient develops a skin reaction while taking Trileptal, consideration should be given to discontinuing Trileptal use and prescribing another antiepileptic medication.

Withdrawal of AEDs

As with all antiepileptic drugs, Trileptal should be withdrawn gradually to minimize the potential of increased seizure frequency.

Cognitive/Neuropsychiatric Adverse Events

Use of Trileptal® (oxcarbazepine) has been associated with central nervous system-related adverse events. The most significant of these can be classified into three general categories: 1) cognitive symptoms including psychomotor slowing, difficulty with concentration, and speech or language problems, 2) somnolence or fatigue, and 3) coordination abnormalities, including ataxia and gait disturbances.

Adult Patients

In one large, fixed-dose study, Trileptal was added to existing AED therapy (up to three concomitant AEDs). By protocol, the dosage of the concomitant AEDs could not be reduced as Trileptal was added, reduction in Trileptal dosage was not allowed if intolerance developed, and patients were discontinued if unable to tolerate their highest target maintenance doses. In this trial, 65% of patients were discontinued because they could not tolerate the 2400 mg/day dose of Trileptal on top of existing AEDs. The adverse events seen in this study were primarily CNS related and the risk for discontinuation was dose related.

In this trial, 7.1% of oxcarbazepine-treated patients and 4% of placebo-treated patients experienced a cognitive adverse event. The risk of discontinuation for these events was about 6.5 times greater on oxcarbazepine than on placebo. In addition, 26% of oxcarbazepine-treated patients and 12% of placebo-treated patients experienced somnolence. The risk of discontinuation for somnolence was about 10 times greater on oxcarbazepine than on placebo. Finally, 28.7% of oxcarbazepine-treated patients and 6.4% of placebo-treated patients experienced ataxia or gait disturbances. The risk for discontinuation for these events was about seven times greater on oxcarbazepine than on placebo.

In a single placebo-controlled monotherapy trial evaluating 2400 mg/day of Trileptal, no patients in either treatment group discontinued double-blind treatment because of cognitive adverse events, somnolence, ataxia, or gait disturbance.

In the two dose-controlled conversion to monotherapy trials comparing 2400 mg/day and 300 mg/day Trileptal, 1.1% of patients in the 2400 mg/day group discontinued double- blind treatment because of somnolence or cognitive adverse events compared to 0% in the 300 mg/day group. In these trials, no patients discontinued because of ataxia or gait disturbances in either treatment group.

Pediatric Patients

A study was conducted in pediatric patients (3 to 17 years old) with inadequately controlled partial seizures in which Trileptal was added to existing AED therapy (up to two concomitant AEDs). By protocol, the dosage of concomitant AEDs could not be reduced as Trileptal was added. Trileptal was titrated to reach a target dose ranging from 30 mg/kg to 46 mg/kg (based on a patient's body weight with fixed doses for predefined weight ranges).

Cognitive adverse events occurred in 5.8% of oxcarbazepine-treated patients (the single most common event being concentration impairment, 4 of 138 patients) and in 3.1% of patients treated with placebo. In addition, 34.8% of oxcarbazepine-treated patients and 14.0% of placebo-treated patients experienced somnolence. (No patient discontinued due to a cognitive adverse event or somnolence.). Finally, 23.2% of oxcarbazepine-treated patients and 7.0% of placebo-treated patients experienced ataxia or gait disturbances. Two (1.4%) oxcarbazepine-treated patients and 1 (0.8%) placebo-treated patient discontinued due to ataxia or gait disturbances.

Multi-Organ Hypersensitivity

Multi-organ hypersensitivity reactions have occurred in close temporal association (median time to detection 13 days: range 4-60) to the initiation of Trileptal therapy in adult and pediatric patients. Although there have been a limited number of reports, many of these cases resulted in hospitalization and some were considered life threatening. Signs and symptoms of this disorder were diverse; however, patients typically, although not exclusively, presented with fever and rash associated with other organ system involvement. Other organ systems and manifestations included hemic and lymphatic (e.g., eosinophilia, thrombocytopenia, lymphadenopathy, leukopenia, neutropenia, splenomegaly), hepatobiliary (e.g., hepatitis, liver function test abnormalities), renal (e.g., proteinuria, nephritis, oliguria, renal failure), muscles and joints (e.g., joint swelling, myalgia, arthralgia, asthenia), nervous system (e.g., hepatic encephalopathy), respiratory (e.g., dyspnea, pulmonary edema, asthma, bronchospasm, interstitial lung disease), hepatorenal syndrome, pruritus, and angioedema. Because the disorder is variable in its expression, other organ system symptoms and signs, not noted here, may occur. If this reaction is suspected, Trileptal should be discontinued and an alternative treatment started. Although there are no case reports to indicate cross sensitivity with other drugs that produce this syndrome, the experience amongst drugs associated with multi-organ hypersensitivity would indicate this to be a possibility (see WARNINGS, Patients with a Past History of Hypersensitivity Reaction to Carbamazepine subsection).

Hematologic Events

Very rare reports of agranulocytosis, aplastic anemia and pancytopenia have been seen in patients treated with Trileptal during post-marketing experience. Discontinuation of the drug should be considered if any evidence of these hematologic events develop.

Laboratory Tests

Serum sodium levels below 125 mmol/L have been observed in patients treated with Trileptal (see WARNINGS section). Experience from clinical trials indicates that serum sodium levels return toward normal when the Trileptal dosage is reduced or discontinued, or when the patient was treated conservatively (e.g., fluid restriction).

Laboratory data from clinical trials suggest that Trileptal use was associated with decreases in T₄, without changes in T₃ or TSH.

Carcinogenesis/Mutagenesis/Impairment of Fertility

In two-year carcinogenicity studies, oxcarbazepine was administered in the diet at doses of up to 100 mg/kg/day to mice and by gavage at doses of up to 250 mg/kg to rats, and the pharmacologically active 10-hydroxy metabolite (MHD) was administered orally at doses of up to 600 mg/kg/day to rats. In mice, a dose-related increase in the incidence of hepatocellular adenomas was observed at oxcarbazepine doses ≥ 70 mg/kg/day or approximately 0.1 times the maximum recommended human dose (MRHD) on a mg/m² basis. In rats, the incidence of hepatocellular carcinomas was increased in females treated with oxcarbazepine at doses ≥ 25 mg/kg/day (0.1 times the MRHD on a mg/m² basis), and incidences of hepatocellular adenomas and/or carcinomas were increased in males and females treated with MHD at doses of 600 mg/kg/day (2.4 times the MRHD on a mg/m² basis) and ≥ 250 mg/kg/day (equivalent to the MRHD on a mg/m² basis), respectively. There was an increase in the incidence of benign testicular interstitial cell tumors in rats at 250 mg oxcarbazepine/kg/day and at ≥ 250 mg MHD/kg/day, and an increase in the incidence of granular cell tumors in the cervix and vagina in rats at 600 mg MHD/kg/day.

Oxcarbazepine increased mutation frequencies in the Ames test in vitro in the absence of metabolic activation in one of five bacterial strains. Both oxcarbazepine and MHD produced increases in chromosomal aberrations and polyploidy in the Chinese hamster ovary assay in vitro in the absence of metabolic activation. MHD was negative in the Ames test, and no mutagenic or clastogenic activity was found with either oxcarbazepine or MHD in V79 Chinese hamster cells in vitro. Oxcarbazepine and MHD were both negative for clastogenic or aneugenic effects (micronucleus formation) in an in vivo rat bone marrow assay.

In a fertility study in which rats were administered MHD (50, 150, or 450 mg/kg) orally prior to and during mating and early gestation, estrous cyclicity was disrupted and numbers of corpora lutea, implantations, and live embryos were reduced in females receiving the highest dose (approximately two times the MRHD on a mg/m² basis).

Pregnancy Category C

Increased incidences of fetal structural abnormalities and other manifestations of developmental toxicity (embryolethality, growth retardation) were observed in the offspring of animals treated with either oxcarbazepine or its active 10-hydroxy metabolite (MHD) during pregnancy at doses similar to the maximum recommended human dose.

When pregnant rats were given oxcarbazepine (30, 300, or 1000 mg/kg) orally throughout the period of organogenesis, increased incidences of fetal malformations (craniofacial, cardiovascular, and skeletal) and variations were observed at the intermediate and high doses (approximately 1.2 and 4 times, respectively, the maximum recommended human dose [MRHD] on a mg/m² basis). Increased embryofetal death and decreased fetal body weights were seen at the high dose. Doses ≥ 300 mg/kg were also maternally toxic (decreased body weight gain, clinical signs), but there is no evidence to suggest that teratogenicity was secondary to the maternal effects.

In a study in which pregnant rabbits were orally administered MHD (20, 100, or 200 mg/kg) during organogenesis, embryofetal mortality was increased at the highest dose (1.5 times the MRHD on a mg/m² basis). This dose produced only minimal maternal toxicity.

In a study in which female rats were dosed orally with oxcarbazepine (25, 50, or 150 mg/kg) during the latter part of gestation and throughout the lactation period, a persistent reduction in body weights and altered behavior (decreased activity) were observed in offspring exposed to the highest dose (0.6 times the MRHD on a mg/m² basis). Oral administration of MHD (25, 75, or 250 mg/kg) to rats during gestation and lactation resulted in a persistent reduction in offspring weights at the highest dose (equivalent to the MRHD on a mg/m² basis).

There are no adequate and well-controlled clinical studies of Trileptal in pregnant women; however, Trileptal is closely related structurally to carbamazepine, which is considered to be teratogenic in humans. Given this fact, and the results of the animal studies described, it is likely that Trileptal is a human teratogen. Trileptal should be used during pregnancy only if the potential benefit justifies the potential risk to the fetus.

Labor and Delivery

The effect of Trileptal on labor and delivery in humans has not been evaluated.

Nursing Mothers

Oxcarbazepine and its active metabolite (MHD) are excreted in human breast milk. A milk-to- plasma concentration ratio of 0.5 was found for both. Because of the potential for serious adverse reactions to Trileptal in nursing infants, a decision should be made about whether to discontinue nursing or to discontinue the drug in nursing women, taking into account the importance of the drug to the mother.

Patients with Renal Impairment

In renally-impaired patients (creatinine clearance < 30 mL/min), the elimination half-life of MHD is prolonged with a corresponding two-fold increase in AUC (see CLINICAL PHARMACOLOGY, Pharmacokinetics subsection). Trileptal therapy should be initiated at one-half the usual starting dose and increased, if necessary, at a slower than usual rate until the desired clinical response is achieved.

Pediatric Use

Trileptal is indicated for use as adjunctive therapy for partial seizures in patients aged 2-16 years. Trileptal is also indicated as monotherapy for partial seizures in patients aged 4-16 years. Trileptal has been given to 898 patients between the ages of 1 month-17 years in controlled clinical trials (332 treated as monotherapy) and about 677 patients between the ages of 1 month-17 years in other trials. (See ADVERSE REACTIONS section for a description of the adverse events associated with Trileptal use in this population.)

Geriatric Use

There were 52 patients over age 65 in controlled clinical trials and 565 patients over the age of 65 in other trials. Following administration of single (300 mg) and multiple (600 mg/day) doses of Trileptal in elderly volunteers (60-82 years of age), the maximum plasma concentrations and AUC values of MHD were 30%-60% higher than in younger volunteers (18-32 years of age). Comparisons of creatinine clearance in young and elderly volunteers indicate that the difference was due to age-related reductions in creatinine clearance.

Last updated on RxList: 4/8/2008

Human Overdose Experience

Isolated cases of overdose with Trileptal® (oxcarbazepine) have been reported. The maximum dose taken was approximately 24,000 mg. All patients recovered with symptomatic treatment.

Treatment and Management

There is no specific antidote. Symptomatic and supportive treatment should be administered as appropriate. Removal of the drug by gastric lavage and/or inactivation by administering activated charcoal should be considered.

Trileptal® (oxcarbazepine) should not be used in patients with a known hypersensitivity to oxcarbazepine or to any of its components.

Last updated on RxList: 4/8/2008

Mechanism of Action

The pharmacological activity of Trileptal® (oxcarbazepine) is primarily exerted through the 10-monohydroxy metabolite (MHD) of oxcarbazepine (see Metabolism and Excretion subsection). The precise mechanism by which oxcarbazepine and MHD exert their antiseizure effect is unknown; however, in vitro electrophysiological studies indicate that they produce blockade of voltage-sensitive sodium channels, resulting in stabilization of hyperexcited neural membranes, inhibition of repetitive neuronal firing, and diminution of propagation of synaptic impulses. These actions are thought to be important in the prevention of seizure spread in the intact brain. In addition, increased potassium conductance and modulation of high-voltage activated calcium channels may contribute to the anticonvulsant effects of the drug. No significant interactions of oxcarbazepine or MHD with brain neurotransmitter or modulator receptor sites have been demonstrated.

Pharmacodynamics

Oxcarbazepine and its active metabolite (MHD) exhibit anticonvulsant properties in animal seizure models. They protected rodents against electrically induced tonic extension seizures and, to a lesser degree, chemically induced clonic seizures, and abolished or reduced the frequency of chronically recurring focal seizures in Rhesus monkeys with aluminum implants. No development of tolerance (i.e., attenuation of anticonvulsive activity) was observed in the maximal electroshock test when mice and rats were treated daily for five days and four weeks, respectively, with oxcarbazepine or MHD.

Pharmacokinetics

Following oral administration of Trileptal tablets, oxcarbazepine is completely absorbed and extensively metabolized to its pharmacologically active 10-monohydroxy metabolite (MHD). The half-life of the parent is about two hours, while the half-life of MHD is about nine hours, so that MHD is responsible for most antiepileptic activity.

Based on MHD concentrations, Trileptal tablets and suspension were shown to have similar bioavailability.

After single-dose administration of Trileptal tablets to healthy male volunteers under fasted conditions, the median tmax was 4.5 (range 3 to 13) hours. After single-dose administration of Trileptal oral suspension to healthy male volunteers under fasted conditions, the median tmax was six hours.

In a mass balance study in people, only 2% of total radioactivity in plasma was due to unchanged oxcarbazepine, with approximately 70% present as MHD, and the remainder attributable to minor metabolites.

Effect of Food: Food has no effect on the rate and extent of absorption of oxcarbazepine from Trileptal tablets. Although not directly studied, the oral bioavailability of the Trileptal suspension is unlikely to be affected under fed conditions. Therefore, Trileptal tablets and suspension can be taken with or without food.

Steady-state plasma concentrations of MHD are reached within 2-3 days in patients when Trileptal is given twice a day. At steady state the pharmacokinetics of MHD are linear and show dose proportionality over the dose range of 300 to 2400 mg/day.

Distribution

The apparent volume of distribution of MHD is 49L.

Approximately 40% of MHD is bound to serum proteins, predominantly to albumin. Binding is independent of the serum concentration within the therapeutically relevant range. Oxcarbazepine and MHD do not bind to alpha-1-acid glycoprotein.

Metabolism and Excretion

Oxcarbazepine is rapidly reduced by cytosolic enzymes in the liver to its 10-monohydroxy metabolite, MHD, which is primarily responsible for the pharmacological effect of Trileptal. MHD is metabolized further by conjugation with glucuronic acid. Minor amounts (4% of the dose) are oxidized to the pharmacologically inactive 10,11-dihydroxy metabolite (DHD).

Oxcarbazepine is cleared from the body mostly in the form of metabolites which are predominantly excreted by the kidneys. More than 95% of the dose appears in the urine, with less than 1% as unchanged oxcarbazepine. Fecal excretion accounts for less than 4% of the administered dose. Approximately 80% of the dose is excreted in the urine either as glucuronides of MHD (49%) or as unchanged MHD (27%); the inactive DHD accounts for approximately 3% and conjugates of MHD and oxcarbazepine account for 13% of the dose.

Special Populations

Hepatic Impairment

The pharmacokinetics and metabolism of oxcarbazepine and MHD were evaluated in healthy volunteers and hepatically-impaired subjects after a single 900-mg oral dose. Mild-to- moderate hepatic impairment did not affect the pharmacokinetics of oxcarbazepine and MHD. No dose adjustment for Trileptal is recommended in patients with mild-to-moderate hepatic impairment. The pharmacokinetics of oxcarbazepine and MHD have not been evaluated in severe hepatic impairment and, therefore, caution should be exercised when dosing severely impaired patients.

Renal Impairment

There is a linear correlation between creatinine clearance and the renal clearance of MHD. When Trileptal is administered as a single 300-mg dose in renally-impaired patients (creatinine clearance < 30 mL/min), the elimination half-life of MHD is prolonged to 19 hours, with a two-fold increase in AUC. Dose adjustment for Trileptal is recommended in these patients (see PRECAUTIONS and DOSAGE AND ADMINISTRATION sections).

Pediatric Use

Weight-adjusted MHD clearance decreases as age and weight increases, approaching that of adults. The mean weight-adjusted clearance in children 2 years- < 4 years of age is approximately 80% higher on average than that of adults. Therefore, MHD exposure in these children is expected to be about one-half that of adults when treated with a similar weight- adjusted dose. The mean weight-adjusted clearance in children 4-12 years of age is approximately 40% higher on average than that of adults. Therefore, MHD exposure in these children is expected to be about three-quarters that of adults when treated with a similar weight-adjusted dose. As weight increases, for patients 13 years of age and above, the weight- adjusted MHD clearance is expected to reach that of adults.

Geriatric Use

Following administration of single (300 mg) and multiple (600 mg/day) doses of Trileptal to elderly volunteers (60-82 years of age), the maximum plasma concentrations and AUC values of MHD were 30%-60% higher than in younger volunteers (18-32 years of age). Comparisons of creatinine clearance in young and elderly volunteers indicate that the difference was due to age-related reductions in creatinine clearance.

Gender

No gender-related pharmacokinetic differences have been observed in children, adults, or the elderly.

Race

No specific studies have been conducted to assess what effect, if any, race may have on the disposition of oxcarbazepine.

Clinical Studies

The effectiveness of Trileptal® (oxcarbazepine) as adjunctive and monotherapy for partial seizures in adults, and as adjunctive therapy in children aged 2-16 years was established in seven multicenter, randomized, controlled trials.

The effectiveness of Trileptal as monotherapy for partial seizures in children aged 4-16 years was determined from data obtained in the studies described, as well as by pharmacokinetic/pharmacodynamic considerations.

Trileptal Monotherapy Trials

Four randomized, controlled, double-blind, multicenter trials, conducted in a predominately adult population, demonstrated the efficacy of Trileptal as monotherapy. Two trials compared Trileptal to placebo and two trials used a randomized withdrawal design to compare a high dose (2400 mg) with a low dose (300 mg) of Trileptal, after substituting Trileptal 2400 mg/day for one or more antiepileptic drugs (AEDs). All doses were administered on a BID schedule. A fifth randomized, controlled, rater-blind, multicenter study, conducted in a pediatric population, failed to demonstrate a statistically significant difference between low and high dose Trileptal treatment groups.

One placebo-controlled trial was conducted in 102 patients (11-62 years of age) with refractory partial seizures who had completed an inpatient evaluation for epilepsy surgery. Patients had been withdrawn from all AEDs and were required to have 2-10 partial seizures within 48 hours prior to randomization. Patients were randomized to receive either placebo or Trileptal given as 1500 mg/day on Day 1 and 2400 mg/day thereafter for an additional nine days, or until one of the following three exit criteria occurred: 1) the occurrence of a fourth partial seizure, excluding Day 1, 2) two new-onset secondarily generalized seizures, where such seizures were not seen in the one-year period prior to randomization, or 3) occurrence of serial seizures or status epilepticus. The primary measure of effectiveness was a between-group comparison of the time to meet exit criteria. There was a statistically significant difference in favor of Trileptal (see Figure 1), p=0.0001.

Figure 1: Kaplan-Meier Estimates of Exit Rate by Treatment Group

The second placebo-controlled trial was conducted in 67 untreated patients (8-69 years of age) with newly-diagnosed and recent-onset partial seizures. Patients were randomized to placebo or Trileptal, initiated at 300 mg BID and titrated to 1200 mg/day (given as 600 mg BID) in six days, followed by maintenance treatment for 84 days. The primary measure of effectiveness was a between-group comparison of the time to first seizure. The difference between the two treatments was statistically significant in favor of Trileptal (see Figure 2), p=0.046.

Figure 2: Kaplan-Meier Estimates of First Seizure Event Rate by Treatment Group

A third trial substituted Trileptal monotherapy at 2400 mg/day for carbamazepine in 143 patients (12-65 years of age) whose partial seizures were inadequately controlled on carbamazepine (CBZ) monotherapy at a stable dose of 800 to 1600 mg/day, and maintained this Trileptal dose for 56 days (baseline phase). Patients who were able to tolerate titration of Trileptal to 2400 mg/day during simultaneous carbamazepine withdrawal were randomly assigned to either 300 mg/day of Trileptal or 2400 mg/day Trileptal. Patients were observed for 126 days or until one of the following four exit criteria occurred: 1) a doubling of the 28- day seizure frequency compared to baseline, 2) a two-fold increase in the highest consecutive two-day seizure frequency during baseline, 3) a single generalized seizure if none had occurred during baseline, or 4) a prolonged generalized seizure. The primary measure of effectiveness was a between-group comparison of the time to meet exit criteria. The difference between the curves was statistically significant in favor of the Trileptal 2400 mg/day group (see Figure 3), p=0.0001.

Figure 3: Kaplan-Meier Estimates of Exit Rate by Treatment Group

Another monotherapy substitution trial was conducted in 87 patients (11-66 years of age) whose seizures were inadequately controlled on one or two AEDs. Patients were randomized to either Trileptal 2400 mg/day or 300 mg/day and their standard AED regimen(s) were eliminated over the first six weeks of double-blind therapy. Double-blind treatment continued for another 84 days (total double-blind treatment of 126 days) or until one of the four exit criteria described for the previous study occurred. The primary measure of effectiveness was a between-group comparison of the percentage of patients meeting exit criteria. The results were statistically significant in favor of the Trileptal 2400 mg/day group (14/34; 41.2%) compared to the Trileptal 300 mg/day group (42/45; 93.3%) (p < 0.0001). The time to meeting one of the exit criteria was also statistically significant in favor of the Trileptal 2400 mg/day group (see Figure 4), p=0.0001.

Figure 4: Kaplan-Meier Estimates of Exit Rate by Treatment Group

A monotherapy trial was conducted in 92 pediatric patients (1 month to 16 years of age) with inadequately-controlled or new-onset partial seizures. Patients were hospitalized and randomized to either Trileptal 10 mg/kg/day or were titrated up to 40-60 mg/kg/day within three days while withdrawing the previous AED on the second day of Trileptal therapy. Seizures were recorded through continuous video-EEG monitoring from Day 3 to Day 5. Patients either completed the 5-day treatment or met one of the two exit criteria: 1) three study-specific seizures (i.e., electrographic partial seizures with a behavioral correlate), 2) a prolonged study-specific seizure. The primary measure of effectiveness was a between-group comparison of the time to meet exit criteria in which the difference between the curves was not statistically significant (p=0.904). The majority of patients from both dose groups completed the 5-day study without exiting.

Although this study failed to demonstrate an effect of oxcarbazepine as monotherapy in pediatric patients, several design elements, including the short treatment and assessment period, the absence of a true placebo, and the likely persistence of plasma levels of previously administered AEDs during the treatment period, make the results uninterpretable. For this reason, the results do not undermine the conclusion, based on pharmacokinetic/pharmacodynamic considerations, that oxcarbazepine is effective as monotherapy in pediatric patients 4 years old and older.

Trileptal Adjunctive Therapy Trials

The effectiveness of Trileptal as an adjunctive therapy for partial seizures was established in two multicenter, randomized, double-blind, placebo-controlled trials, one in 692 patients (15-66 years of age) and one in 264 pediatric patients (3-17 years of age), and in one multicenter, rater-blind, randomized, age-stratified, parallel-group study comparing two doses of oxcarbazepine in 128 pediatric patients (1 month to < 4 years of age).

Patients in the two placebo-controlled trials were on 1-3 concomitant AEDs. In both of the trials, patients were stabilized on optimum dosages of their concomitant AEDs during an 8-week baseline phase. Patients who experienced at least 8 (minimum of 1-4 per month) partial seizures during the baseline phase were randomly assigned to placebo or to a specific dose of Trileptal in addition to their other AEDs.

In these studies, the dose was increased over a two-week period until either the assigned dose was reached, or intolerance prevented increases. Patients then entered a 14- (pediatrics) or 24-week (adults) maintenance period.

In the adult trial, patients received fixed doses of 600, 1200 or 2400 mg/day. In the pediatric trial, patients received maintenance doses in the range of 30-46 mg/kg/day, depending on baseline weight. The primary measure of effectiveness in both trials was a between-group comparison of the percentage change in partial seizure frequency in the double- blind treatment phase relative to baseline phase. This comparison was statistically significant in favor of Trileptal at all doses tested in both trials (p=0.0001 for all doses for both trials). The number of patients randomized to each dose, the median baseline seizure rate, and the median percentage seizure rate reduction for each trial are shown in Table 1. It is important to note that in the high-dose group in the study in adults, over 65% of patients discontinued treatment because of adverse events; only 46 (27%) of the patients in this group completed the 28-week study (see ADVERSE REACTIONS section), an outcome not seen in the monotherapy studies.

Table 1: Summary of Percentage Change in Partial Seizure Frequency from Baseline for Placebo-Controlled Adjunctive Therapy Trials

Trial	Treatment Group	N	Baseline Median Seizure Rate*	Median % Reduction
1 (pediatrics)	Trileptal	136	12.5	34.81
	Placebo	128	13.1	9.4
2 (adults)	Trileptal 2400 mg/day	174	10.0	49.91
	Trileptal 1200 mg/day	177	9.8	40.21
	Trileptal 600 mg/day	168	9.6	26.41
	Placebo	173	8.6	7.6
1 p=0.0001; * = # per 28 days

Subset analyses of the antiepileptic efficacy of Trileptal with regard to gender in these trials revealed no important differences in response between men and women. Because there were very few patients over the age of 65 in controlled trials, the effect of the drug in the elderly has not been adequately assessed.

The third adjunctive therapy trial enrolled 128 pediatric patients (1 month to < 4 years of age) with inadequately-controlled partial seizures on 1-2 concomitant AEDs. Patients who experienced at least 2 study-specific seizures (i.e., electrographic partial seizures with a behavioral correlate) during the 72-hour baseline period were randomly assigned to either Trileptal 10 mg/kg/day or were titrated up to 60 mg/kg/day within 26 days. Patients were maintained on their randomized target dose for 9 days and seizures were recorded through continuous video-EEG monitoring during the last 72 hours of the maintenance period. The primary measure of effectiveness in this trial was a between-group comparison of the change in seizure frequency per 24 hours compared to the seizure frequency at baseline. For the entire group of patients enrolled, this comparison was statistically significant in favor of Trileptal 60 mg/kg/day. In this study, there was no evidence that Trileptal was effective in patients below the age of 2 years (N=75).

Last updated on RxList: 4/8/2008

Anaphylactic reactions and angioedema may occur during treatment with Trileptal. Patients should be advised to report immediately signs and symptoms suggesting angioedema (swelling of the face, eyes, lips, tongue or difficulty in swallowing or breathing) and to stop taking the drug until they have consulted with their physician (see WARNINGS, Anaphylactic Reactions and Angioedema subsection).

Patients who have exhibited hypersensitivity reactions to carbamazepine should be informed that approximately 25%-30% of these patients may experience hypersensitivity reactions with Trileptal. Patients should be advised that if they experience a hypersensitivity reaction while taking Trileptal they should consult with their physician immediately (see WARNINGS, Patients with a Past History of Hypersensitivity Reaction to Carbamazepine subsection).

Patients should be advised that serious skin reactions have been reported in association with Trileptal. In the event a skin reaction should occur while taking Trileptal, patients should consult with their physician immediately (see WARNINGS, Serious Dermatological Reactions subsection).

Patients should be instructed that a fever associated with other organ system involvement (rash, lymphadenopathy, etc.) may be drug related and should be reported to the physician immediately (see PRECAUTIONS, Multi-Organ Hypersensitivity subsection).

Patients should be advised that there have been very rare reports of blood disorders reported in patients treated with Trileptal. Patients should be instructed to immediately consult with their physician if they experience symptoms suggestive of blood disorders (see PRECAUTIONS, Hematologic Events subsection).

Female patients of childbearing age should be warned that the concurrent use of Trileptal with hormonal contraceptives may render this method of contraception less effective (see DRUG INTERACTIONS subsection). Additional non-hormonal forms of contraception are recommended when using Trileptal.

Caution should be exercised if alcohol is taken in combination with Trileptal therapy, due to a possible additive sedative effect.

Patients should be advised that Trileptal may cause dizziness and somnolence. Accordingly, patients should be advised not to drive or operate machinery until they have gained sufficient experience on Trileptal to gauge whether it adversely affects their ability to drive or operate machinery.

Last updated on RxList: 4/8/2008

IMPORTANT NOTE: This is a summary and does not contain all possible information about this product. For complete information about this product or your specific health needs, ask your health care professional. Always seek the advice of your health care professional if you have any questions about this product or your medical condition. This information is not intended as individual medical advice and does not substitute for the knowledge and judgment of your health care professional. This information does not contain any assurances that this product is safe, effective, or appropriate for you.

OXCARBAZEPINE - ORAL

(ox-kar-BAY-zih-peen)

COMMON BRAND NAME(S): Trileptal

USES: This medication is used to treat seizure disorders (epilepsy). It may be used with other seizure medications as determined by your doctor.

HOW TO USE: Take this medication by mouth, usually twice daily. This drug may be taken with or without food.

The dosage is based on your medical condition and response to therapy.

It is important to take all doses on time to keep the level of medication in your blood constant. Take doses at evenly spaced intervals. Do not skip doses.

Do not suddenly stop taking this drug without your doctor's approval since seizures may reoccur.

Notify your doctor if seizure control worsens.

SIDE EFFECTS: Dizziness, drowsiness, fatigue, nausea, vomiting, headache, trouble sleeping, acne, dry mouth, or constipation may occur. If any of these effects persist or worsen, contact your doctor or pharmacist promptly.

Remember that your doctor has prescribed this medication because he or she has judged that the benefit to you is greater than the risk of side effects. Many people using this medication do not have serious side effects.

This medication rarely may cause mood or behavior changes, such as anxiety, agitation, hostility, pressured/rapid speech, or thoughts of suicide. Tell your doctor immediately if you develop unusual (possibly sudden) mood changes.

Tell your doctor immediately if you develop any of these serious side effects: double vision, change in vision, involuntary eye movements, difficulty speaking, difficulty concentrating, loss of coordination, trouble walking (abnormal gait), uncontrolled muscle movements (tremor), dulled sense of touch.

Tell your doctor immediately if you develop any of these unlikely but very serious side effects: easy bleeding/bruising, chest pain, mental/mood changes, persistent sore throat, stomach/abdominal pain, bloody stool, dark urine, change in amount of urine, yellowing of eyes/skin.

A serious allergic reaction to this drug is unlikely, but seek immediate medical attention if it occurs. Symptoms of a serious allergic reaction include: fever, rash, itching, swelling (e.g., face, tongue or lymph nodes), severe dizziness, trouble breathing.

This is not a complete list of possible side effects. If you notice other effects not listed above, contact your doctor or pharmacist.

Contact your doctor for medical advice about side effects. The following numbers do not provide medical advice, but in the US you may report side effects to the Food and Drug Administration (FDA) at 1-800-FDA-1088. In Canada, you may call Health Canada at 1-866-234-2345.

PRECAUTIONS: Before taking oxcarbazepine, tell your doctor or pharmacist if you are allergic to it; or to carbamazepine; or if you have any other allergies.

Tell your doctor your medical history, including: kidney disease, decreased sodium blood levels (hyponatremia), recent seizures.

This drug may make you dizzy or drowsy; use caution engaging in activities requiring alertness such as driving or using machinery. Limit alcoholic beverages.

Oxcarbazepine is not recommended for use during pregnancy due to potential harm to an unborn baby. Consult your doctor for more details.

This medication passes into breast milk and may have undesirable effects on a nursing infant. Because of the potential risk to the infant, breast-feeding while using this drug is not recommended. Consult your doctor before breast-feeding.

DRUG INTERACTIONS: Your doctor or pharmacist may already be aware of any possible drug interactions and may be monitoring you for them. Do not start, stop, or change the dosage of any medicine before checking with them first.

Before using this medication, tell your doctor or pharmacist of all prescription and nonprescription medication you may use, especially: calcium channel blockers (e.g., verapamil, felodipine), other seizure control medication (e.g., carbamazepine, phenytoin, phenobarbital, valproic acid).

This medication may decrease the effectiveness of combination-type birth control pills. You may need to use an additional form of reliable birth control while using this medication. Consult your doctor or pharmacist.

Tell your doctor if you take any drugs that make you drowsy, such as: medicine for sleep, sedatives, tranquilizers, anti-anxiety drugs (e.g., diazepam), narcotic pain relievers (e.g., hydrocodone, codeine), psychiatric medicines (e.g., phenothiazines such as chlorpromazine, or tricyclics such as amitriptyline), muscle relaxants, antihistamines that cause drowsiness (e.g., diphenhydramine).

Check the labels on all your medicines (e.g., cough-and-cold products) because they may contain ingredients that cause drowsiness. Ask your pharmacist about the safe use of those products.

This document does not contain all possible interactions. Therefore, before using this product, tell your doctor or pharmacist of all the products you use. Keep a list of all your medications with you, and share the list with your doctor and pharmacist.

OVERDOSE: If overdose is suspected, contact your local poison control center or emergency room immediately. US residents can call the US national poison hotline at 1-800-222-1222. Canadian residents should call their local poison control center directly.

NOTES: It is recommended you wear or carry identification indicating you are using this drug.

Do not share this medication with others.

Laboratory and/or medical tests (e.g., sodium levels, pregnancy tests) may be performed to monitor your therapy.

MISSED DOSE: If you miss a dose, use it as soon as you remember. If it is near the time of the next dose, skip the missed dose and resume your usual dosing schedule. Do not double the dose to catch up.

STORAGE: Store at room temperature at 77 degrees F (25 degrees C) in a tight container away from light and moisture. Brief storage between 59-86 degrees F (15-30 degrees C) is permitted. Do not store in the bathroom. Keep all medicines away from children and pets.

Do not flush medications down the toilet or pour them into a drain unless instructed to do so. Properly discard this product when it is expired or no longer needed. Consult your pharmacist or local waste disposal company for more details about how to safely discard your product.

MEDICAL ALERT: Your condition can cause complications in a medical emergency. For enrollment information call MedicAlert at 1-800-854-1166 (USA), or 1-800-668-1507 (Canada).

Information last revised July 2008 Copyright(c) 2008 First DataBank, Inc.