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Qudexy XR

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Qudexy XR

Side Effects
Interactions

SIDE EFFECTS

The following adverse reactions are discussed in more detail in other sections of the labeling:

Clinical Trials Experience With Immediate-Release Topiramate

Because clinical trials are conducted under widely varying conditions, adverse reaction rates observed in the clinical trials of a drug cannot be directly compared to rates in the clinical trials of another drug and may not reflect the rates observed in clinical practice.

Adverse Reactions Observed in Monotherapy Trial

Adults 17 Years and Older

The adverse reactions in the monotherapy controlled trial (Study 1) that occurred most commonly in adults in the 400 mg per day group (incidence greater than or equal to 5%) and at a rate higher than the 50 mg per day group were paresthesia, weight decrease, somnolence, anorexia, dizziness, and difficulty with memory [see Table 2] [see Clinical Studies].

Approximately 21% of the 159 adult patients in the 400 mg per day group who received topiramate as monotherapy in Study 1 discontinued therapy due to adverse reactions. The most common (greater than or equal to 2% more frequent than low-dose 50 mg per day topiramate) adverse reactions causing discontinuation in this trial were difficulty with memory, fatigue, asthenia, insomnia, somnolence and paresthesia.

Pediatric Patients 10 Years to 16 Years of Age

The adverse reactions in the controlled trial (Study 1) that occurred most commonly in children (10 years up to 16 years of age) in the 400 mg per day topiramate group (incidence greater than or equal to 5%) and at a rate higher than in the 50 mg per day group were weight decrease, upper respiratory tract infection, paresthesia, anorexia, diarrhea, and mood problems [see Table 3] [see Clinical Studies].

Approximately 12% of the 57 pediatric patients in the 400 mg per day group who received topiramate as monotherapy in the controlled clinical trial discontinued therapy due to adverse reactions. The most common (greater than 5%) adverse reactions resulting in discontinuation in this trial were difficulty with concentration/attention.

Table 2: Incidence of Treatment-Emergent Adverse Reaction in the Monotherapy Epilepsy Trial in Adultsa Where Incidence Was at Least 2% in the 400 mg/day Immediate-Release Topiramate Group and Greater Than the Rate in the 50 mg/day Immediate-Release Topiramate Group

Body System/ Adverse Reaction Immediate-release topiramate Dosage (mg/day)
50
(N=160)
400
(N=159)
Body as a Whole-General Disorders
  Asthenia 4 6
  Leg Pain 2 3
  Chest Pain 1 2
Central & Peripheral Nervous System Disorders
  Paresthesia 21 40
  Dizziness 13 14
  Hypoasthesia 4 5
  Ataxia 3 4
  Hypertonia 0 3
Gastro-intestinal System Disorders
  Diarrhea 5 6
  Constipation 1 4
  Gastritis 0 3
  Dry Mouth 1 3
  Gastroesophageal Reflux 1 2
Liver and Biliary System Disorders
  Gamma-GT Increased 1 3
Metabolic and Nutritional Disorders
  Weight Decrease 6 16
Psychiatric Disorders
  Somnolence 9 15
  Anorexia 4 14
  Difficulty with Memory NOS  5 10
  Insomnia 8 9
  Depression 7 9
  Difficulty with Concentration/Attention 7 8
  Anxiety 4 6
  Psychomotor Slowing 3 5
  Mood Problems 2 5
  Confusion 3 4
  Cognitive Problem NOS 1 4
  Libido Decreased 0 3
Reproductive Disorders, Female
  Vaginal Hemorrhage 0 3
Red Blood Cell Disorders
  Anemia 1 2
Resistance Mechanism Disorders
  Infection Viral 6 8
  Infection 2 3
Respiratory System Disorders
  Bronchitis 3 4
  Rhinitis 2 4
  Dyspnea 1 2
Skin and Appendages Disorders
  Rash 1 4
  Pruritus 1 4
  Acne 2 3
Special Senses Other, Disorders
  Taste Perversion 3 5
Urinary System Disorders
  Cystitis 1 3
  Renal Calculus 0 3
  Urinary Tract Infection 1 2
  Dysuria 0 2
  Micturition Frequency 0 2
aValues represent the percentage of patients reporting a given adverse reaction. Patients may have reported more than one adverse reaction during the study and can be included in more than one adverse reaction category

Table 3: Incidence of Treatment-Emergent Adverse Reactions in the Monotherapy Epilepsy Trial in Pediatric Patients (Ages 10 up to 16 Years)a Where Incidence Was at Least 5% in the 400 mg/day Immediate-Release Topiramate Group and Greater than the Rate in the 50mg/day Immediate-Release Topiramate Group

Body System/ Adverse Reaction Immediate-release topiramate Dosage (mg/day)
50
(N=57)
400
(N=57)
Body as a Whole-General Disorders
  Fever 0 9
Central & Peripheral Nervous System Disorders
  Paresthesia 2 16
Gastro-Intestinal System Disorders
  Diarrhea 5 11
Metabolic and Nutritional Disorders
  Weight Decrease 7 21
Psychiatric Disorders
  Anorexia 11 14
  Mood Problems 2 11
  Difficulty with Concentration/Attention 4 9
  Cognitive Problem NOS 0 7
  Nervousness 4 5
Resistance Mechanism Disorders
  Infection Viral 4 9
  Infection 2 7
Respiratory System Disorders
  Upper Respiratory Tract Infection 16 18
  Rhinitis 2 7
  Bronchitis 2 7
  Sinusitis 2 5
  Skin and Appendages Disorders Alopecia 2 5
aValues represent the percentage of patients reporting a given adverse event. Patients may have reported more than one adverse event during the study and can be included in more than one adverse event category

Adverse Reactions Observed in Adjunctive Therapy Epilepsy Trials

The most commonly observed adverse reactions associated with the use of topiramate at dosages of 200 to 400 mg per day in controlled trials in adults with partial onset seizures, primary generalized tonic-clonic seizures, or Lennox-Gastaut syndrome that were seen at greater frequency in topiramate-treated patients and did not appear to be dose-related were: somnolence, ataxia, speech disorders and related speech problems, psychomotor slowing, abnormal vision, difficulty with memory, paresthesia and diplopia [see Table 4] [see Clinical Studies]. The most common dose-related adverse reactions at dosages of 200 mg to 1,000 mg per day were: fatigue, nervousness, difficulty with concentration or attention, confusion, depression, anorexia, language problems, anxiety, mood problems, and weight decrease [see Table 6].

Adverse reactions associated with the use of topiramate at dosages of 5 mg/kg/day to 9 mg/kg/day in controlled trials in pediatric patients with partial onset seizures, primary generalized tonic-clonic seizures, or Lennox-Gastaut syndrome that were seen at greater frequency in topiramate-treated patients were: fatigue, somnolence, anorexia, nervousness, difficulty with concentration/attention, difficulty with memory, aggressive reaction, and weight decrease [see Table 7].

In controlled clinical trials in adults, 11% of patients receiving topiramate 200 to 400mg per day as adjunctive therapy discontinued due to adverse reactions. This rate appeared to increase at dosages above 400mg per day. Adverse events associated with discontinuing therapy included somnolence, dizziness, anxiety, difficulty with concentration or attention, fatigue, and paresthesia and increased at dosages above 400 mg per day. None of the pediatric patients who received topiramate adjunctive therapy at 5 mg/kg/day to 9 mg/kg/day in controlled clinical trials discontinued due to adverse reactions.

Approximately 28% of the 1757 adults with epilepsy who received topiramate at dosages of 200 mg to 1,600 mg per day in clinical studies discontinued treatment because of adverse reactions; an individual patient could have reported more than one adverse reaction. These adverse reactions were: psychomotor slowing (4.0%), difficulty with memory (3.2%), fatigue (3.2%), confusion (3.1%), somnolence (3.2%), difficulty with concentration/attention (2.9%), anorexia (2.7%), depression (2.6%), dizziness (2.5%), weight decrease (2.5%), nervousness (2.3%), ataxia (2.1%), and paresthesia (2.0%). Approximately 11% of the 310 pediatric patients who received topiramate at dosages up to 30 mg/kg/day discontinued due to adverse reactions. Adverse reactions associated with discontinuing therapy included aggravated convulsions (2.3%), difficulty with concentration/attention (1.6%), language problems (1.3%), personality disorder (1.3%), and somnolence (1.3%).

Incidence in Epilepsy Controlled Clinical Trials – Adjunctive Therapy – Partial Onset Seizures, Primary Generalized Tonic-Clonic Seizures, and Lennox-Gastaut Syndrome

Table 4 lists adverse reactions that occurred in at least 1% of adults treated with 200 to 400 mg per day topiramate in controlled trials that were numerically more common at this dose than in the patients treated with placebo. In general, most patients who experienced adverse reactions during the first eight weeks of these trials no longer experienced them by their last visit. Table 7 lists adverse reactions that occurred in at least 1% of pediatric patients treated with 5 mg/kg to 9 mg/kg topiramate in controlled trials that were numerically more common than in patients treated with placebo.

Other Adverse Reactions Observed During Double-Blind Epilepsy Adjunctive Therapy Trials

Other adverse reactions that occurred in more than 1% of adults treated with 200 mg to 400 mg of topiramate in placebo-controlled epilepsy trials but with equal or greater frequency in the placebo group were headache, injury, anxiety, rash, pain, convulsions aggravated, coughing, fever, diarrhea, vomiting, muscle weakness, insomnia, personality disorder, dysmenorrhea, upper respiratory tract infection, and eye pain.

Table 4: Incidence of Adverse Reactions in Placebo-Controlled, Adjunctive Epilepsy Trials in Adultsa,b,c

Body System/ Adverse Reactionc Placebo
(N=291)
Topiramate Dosage (mg per day)
200-400
(N=183)
600-1,000
(N=414)
Body as a Whole-General Disorders
  Fatigue 13 15 30
  Asthenia 1 6 3
  Back pain 4 5 3
  Chest pain 3 4 2
  Influenza-like symptoms 2 3 4
  Leg pain 2 2 4
  Hot flushes 1 2 1
  Allergy 1 2 3
  Edema 1 2 1
  Body odor 0 1 0
  Rigors 0 1 < 1
Central & Peripheral Nervous System Disorders
  Dizziness 15 25 32
  Ataxia 7 16 14
  Speech disorders/Related speech problems 2 13 11
  Paresthesia 4 11 19
  Nystagmus 7 10 11
  Tremor 6 9 9
  Language problems 1 6 10
  Coordination abnormal 2 4 4
  Hypoaesthesia 1 2 1
  Gait abnormal 1 3 2
  Muscle contractions involuntary 1 2 2
  Stupor 0 2 1
  Vertigo 1 1 2
Gastro-intestinal System Disorders
  Nausea 8 10 12
  Dyspepsia 6 7 6
  Abdominal pain 4 6 7
  Constipation 2 4 3
  Gastroenteritis 1 2 1
  Dry mouth 1 2 4
  Gingivitis < 1 1 1
  GI disorder < 1 1 0
Hearing and Vestibular Disorders
  Hearing decreased 1 2 1
Metabolic and Nutritional Disorders
  Weight decrease 3 9 13
  Musculo-Skeletal System Disorders Myalgia 1 2 2
  Skeletal pain 0 1 0
Platelet, Bleeding & Clotting Disorders
  Epistaxis 1 2 1
Psychiatric Disorders
  Somnolence 12 29 28
  Nervousness 6 16 19
  Psychomotor slowing 2 13 21
  Difficulty with memory 3 12 14
  Anorexia 4 10 12
  Confusion 5 11 14
  Depression 5 5 13
  Difficulty with concentration/attention 2 6 14
  Mood problems 2 4 9
  Agitation 2 3 3
  Aggressive reaction 2 3 3
  Emotional liability 1 3 3
  Cognitive problems 1 3 3
  Libido decreased 1 2 < 1
  Apathy 1 1 3
  Depersonalization 1 1 2
Reproductive Disorders, Female
  Breast pain 2 4 0
  Amenorrhea 1 2 2
  Menorrhagia 0 2 1
  Menstrual disorder 1 2 1
Reproductive Disorders, Male
  Prostatic disorder < 1 2 0
Resistance Mechanism Disorders
  Infection 1 2 1
  Infection viral 1 2 < 1
  Moniliasis < 1 1 0
Respiratory System Disorders
  Pharyngitis 2 6 3
  Rhinitis 6 7 6
  Sinusitis 4 5 6
  Dyspnea 1 1 2
Skin and Appendages Disorders
  Skin disorder < 1 2 1
  Sweating increased < 1 1 < 1
  Rash, erythematous < 1 1 < 1
Special Senses Other, Disorders
  Taste perversion 0 2 4
Urinary System Disorders
  Hematuria 1 2 < 1
  Urinary tract infection 1 2 3
  Micturition frequency 1 1 2
  Urinary incontinence < 1 2 1
  Urine abnormal 0 1 < 1
Vision Disorders
  Vision abnormal 2 13 10
  Diplopia 5 10 10
White Cell and RES Disorders
  Leukopenia 1 2 1
aPatients in these adjunctive trials were receiving 1 to 2 concomitant antiepileptic drugs in addition to topiramate or placebo
bValues represent the percentage of patients reporting a given reaction. Patient may have reported more than one adverse reaction during the study and can be included in more than one adverse reaction category.
cAdverse reactions reported by at least 1% of patients in the topiramate 200 mg to 400 mg per day group and more common than in the placebo group

Adverse Reactions Observed in Adjunctive Therapy Trial in Adults with Partial Onset Seizures (Study 7)

Study 7 was a randomized, double-blind, adjunctive, placebo-controlled, parallel group study with 3 treatment arms: 1) placebo; 2) topiramate 200 mg per day with a 25 mg per day starting dose, increased by 25 mg per day each week for 8 weeks until the 200 mg per day maintenance dose was reached; and 3) topiramate 200 mg per day with a 50 mg per day starting dose, increased by 50 mg per day each week for 4 weeks until the 200 mg per day maintenance dose was reached. All patients were maintained on concomitant carbamazepine with or without another concomitant antiepileptic drug.

The incidence of adverse reactions (Table 5) did not differ significantly between the 2 topiramate regimens. Because the frequencies of adverse reactions reported in this study were markedly lower than those reported in the previous epilepsy studies, they cannot be directly compared with data obtained in other studies.

Table 5: Incidence of Adverse Reactions in Study 7a,b,c

Body System/ Adverse Reactions Placebo
(N=92)
Topiramate Dosage
(mg per day)
200
(N=171)
Body as a Whole-General Disorders
  Fatigue 4 9
  Chest pain 1 2
Cardiovascular Disorders, General
  Hypertension 0 2
Central & Peripheral Nervous System Disorders
  Paresthesia 2 9
  Dizziness 4 7
  Tremor 2 3
  Hypoesthesia 0 2
  Leg cramps 0 2
  Language problems 0 2
Gastro-intestinal System Disorders
  Abdominal pain 3 5
  Constipation 0 4
  Diarrhea 1 2
  Dyspepsia 0 2
  Dry mouth 0 2
Hearing and Vestibular Disorders
  Tinnitus 0 2
Metabolic and Nutritional Disorders
  Weight decrease 4 8
Psychiatric Disorders
  Somnolence 9 15
  Anorexia 7 9
  Nervousness 2 9
  Difficulty with concentration/attention 0 5
  Insomnia 3 4
  Difficulty with memory 1 2
  Aggressive reaction 0 2
Respiratory System Disorders
  Rhinitis 0 4
Urinary System Disorders
  Cystitis 0 2
Vision Disorders
  Diplopia 0 2
  Vision abnormal 0 2
aPatients in these adjunctive trials were receiving 1 to 2 concomitant antiepileptic drugs in addition to topiramate or placebo
bValues represent the percentage of patients reporting a given adverse reaction. Patients may have reported more than one adverse reaction during the study and can be included in more than one adverse reaction category
cAdverse reactions reported by at least 2% of patients in the topiramate 200 mg per day group and more common than in the placebo group

Table 6: Incidence (%) of Dose-Related Adverse Reactions From Placebo-Controlled, Adjunctive Trials in Adults With Partial Onset Seizures (Studies 2 through 7)a

Adverse Reaction Placebo
(N=216)
Topiramate Dosage (mg per day)
200
(N=45)
400
(N=68)
600-1,000
(N=414)
Fatigue 13 11 12 30
Nervousness 7 13 18 19
Difficulty with concentration/attention 1 7 9 14
Confusion 4 9 10 14
Depression 6 9 7 13
Anorexia 4 4 6 12
Language Problems <1 2 9 10
Anxiety 6 2 3 10
Mood Problems 2 0 6 9
Weight Decrease 3 4 9 13
aDose-response studies were not conducted for other adult indications or for pediatric indications

Table 7: Incidence (%) of Adverse Reaction in Placebo-Controlled, Adjunctive Epilepsy Trial in Pediatric Patients (Ages 2 Years to 16 Years)a,b,c (Study 8)

Body System/ Adverse Reaction Placebo
(N=101)
Topiramate
(N=98)
Body as a Whole-General Disorders
  Fatigue 5 16
  Injury 13 14
  Allergic reaction 1 2
  Back pain 0 1
  Pallor 0 1
Cardiovascular Disorders, General
  Hypertension 0 1
Central & Peripheral Nervous System Disorders
  Gait abnormal 5 8
  Ataxia 2 6
  Hyperkinesia 4 5
  Dizziness 2 4
  Speech disorders/Related speech problems 2 4
  Hyporeflexia 0 2
  Convulsions grand mal 0 1
  Fecal incontinence 0 1
  Paresthesia 0 1
Gastro-Intestinal System Disorders
  Nausea 5 6
  Saliva increased 4 6
  Constipation 4 5
  Gastroenteritis 2 3
  Dysphasia 0 1
  Flatulence 0 1
  Gastroesophageal reflux 0 1
  Glossitis 0 1
  Gum hyperplasia 0 1
Heart Rate and Rhythm Disorders
  Bradycardia 0 1
Metabolic and Nutritional Disorders
  Weight decrease 1 9
  Thirst 1 2
  Hypoglycemia 0 1
  Weight increase 0 1
Platelet, Bleeding & Clotting Disorders
  Purpura 4 8
  Epistaxis 1 4
  Hematoma 0 1
  Prothrombin increased 0 1
  Thrombocytopenia 0 1
Psychiatric Disorders
  Somnolence 16 26
  Anorexia 15 24
  Nervousness 7 14
  Personality disorder (Behavior Problems) 9 11
  Difficulty with concentration/attention 2 10
  Aggressive reaction 4 9
  Insomnia 7 8
  Difficulty with memory 0 5
  Confusion 3 4
  Psychomotor slowing 2 3
  Appetite increased 0 1
  Neurosis 0 1
Reproductive Disorders, Female
  Leukorrhea 0 2
Resistance Mechanism Disorders
  Infection viral 3 7
Respiratory System Disorders
  Pneumonia 1 5
  Respiratory disorder 0 1
Skin and Appendages Disorders
  Skin Disorder 2 3
  Alopecia 1 2
  Dermatitis 0 2
  Hypertrichosis 1 2
  Rash erythematous 0 2
  Eczema 0 1
  Seborrhea 0 1
  Skin discoloration 0 1
Urinary System Disorders
  Urinary incontinence 2 4
  Nocturia 0 1
Vision Disorders
  Eye abnormality 1 2
  Vision abnormal 1 2
  Diplopia 0 1
  Lacrimation abnormal 0 1
  Myopia 0 1
White Cell and RES Disorders
  Leukopenia 0 2
aPatients in these adjunctive trials were receiving 1 to 2 concomitant antiepileptic drugs in addition to topiramate or placebo
bValues represent the percentage of patients reporting a given adverse reaction. Patients may have reported more than one adverse reaction during the study and can be included in more than one adverse reaction category
cReactions that Occurred in at Least 1% of Topiramate-Treated Patients and Occurred More Frequently in Topiramate-Treated Than Placebo-Treated Patients

Laboratory Abnormalities

Topiramate decreases serum bicarbonate [see WARNINGS AND PRECAUTIONS].

Immediate-release topiramate treatment was associated with changes in several clinical laboratory analytes in randomized, double-blind, placebo-controlled studies. Similar effects should be anticipated with use of QUDEXY XR.

Controlled trials of adjunctive topiramate treatment of adults for partial onset seizures showed an increased incidence of markedly decreased serum phosphorus (6% topiramate, 2% placebo), markedly increased serum alkaline phosphatase (3% topiramate, 1% placebo), and decreased serum potassium (0.4 % topiramate, 0.1 % placebo). The clinical significance of these abnormalities has not been clearly established.

Changes in several clinical laboratory results (increased creatinine, BUN, alkaline phosphatase, total protein, total eosinophil count and decreased potassium) have been observed in a clinical investigational program in very young (2 years and younger) pediatric patients who were treated with adjunctive topiramate for partial onset seizures [see Use in Specific Populations].

Topiramate treatment produced a dose-related increased shift in serum creatinine from normal at baseline to an increased value at the end of 4 months treatment in adolescent patients (ages 12 years to 16 years) in a double-blind, placebo-controlled study. The incidence of these abnormal shifts was 4% for placebo, 4% for 50 mg, and 18% for 100 mg.

Topiramate treatment with or without concomitant valproic acid (VPA) can cause hyperammonemia with or without encephalopathy [see WARNINGS AND PRECAUTIONS].

Clinical Trials Experience With QUDEXY XR

Because clinical trials are conducted under widely varying conditions, adverse reaction rates observed in the clinical trials of a drug cannot be directly compared to rates in the clinical trials of another drug and may not reflect the rates observed in clinical practice. In the QUDEXY XR study, a dose of 200 mg/day was administered to a limited number of patients; therefore, these results cannot be directly compared to immediate-release topiramate experience.

The safety data presented below are from 249 patients with partial epilepsy on concomitant AEDs who participated in the QUDEXY XR study [see Clinical Studies].

Table 8 displays the incidence of treatment-emergent adverse reactions that occurred in ≥ 2% of patients and numerically greater than placebo.

Table 8: Incidence ( ≥ 2%) of Treatment-Emergent Adverse Reactions in Placebo-Controlled Adjunctive Therapy Clinical Trial in Patients With Partial Onset Seizures

Body System/ Adverse Reaction Placebo
(N=125)
QUDEXY XR (200 mg)
(N=124)
General Disorders
  Fatigue 5 6
  Asthenia 1 2
  Irritability 1 2
Nervous System Disorders
  Somnolence 2 12
  Dizziness 6 7
  Paresthesia 2 7
  Aphasia 0 2
  Dysarthria 1 2
  Memory impairment 1 2
Psychiatric Disorder
  Psychomotor retardation 0 2
Cardiovascular Disorders, General
  Hypertension 1 3
Metabolic and Nutritional Disorders
  Weight decrease 0 7
  Decreased appetite 2 4
  Anorexia 1 2

In the controlled clinical study using QUDEXY XR, 8.9% of patients who received QUDEXY XR and 4.0% who received placebo discontinued as a result of treatment-emergent adverse reactions.

Postmarketing Experience

The following adverse reactions have been identified during post-approval use of topiramate. Because these reactions are reported voluntarily from a population of uncertain size, it is not always possible to reliably estimate their frequency or establish a causal relationship to drug exposure. The listing is alphabetized: bullous skin reactions (including erythema multiforme, Stevens-Johnson syndrome, toxic epidermal necrolysis), hepatic failure (including fatalities), hepatitis, maculopathy, pancreatitis, and pemphigus.

Read the Qudexy XR (topiramate extended-release capsules) Side Effects Center for a complete guide to possible side effects

DRUG INTERACTIONS

Oral Contraceptives

The possibility of decreased contraceptive efficacy and increased breakthrough bleeding should be considered in patients taking combination oral contraceptive products with QUDEXY XR. Patients taking estrogen-containing contraceptives should be asked to report any change in their bleeding patterns. Contraceptive efficacy can be decreased even in the absence of breakthrough bleeding [see CLINICAL PHARMACOLOGY].

Antiepileptic Drugs

Concomitant administration of phenytoin or carbamazepine with topiramate decreased plasma concentrations of topiramate [see CLINICAL PHARMACOLOGY].

Concomitant administration of valproic acid and topiramate has been associated with hyperammonemia with and without encephalopathy. Concomitant administration of topiramate with valproic acid has also been associated with hypothermia (with and without hyperammonemia) in patients who have tolerated either drug alone. It may be prudent to examine blood ammonia levels in patients in whom the onset of hypothermia has been reported [see WARNINGS AND PRECAUTIONS and CLINICAL PHARMACOLOGY].

Numerous AEDs are substrates of the CYP enzyme system. In vitro studies indicate that topiramate does not inhibit enzyme activity for CYP1A2, CYP2A6, CYP2B6, CYP2C9, CYP2D6, CYP2E1, and CYP3A4/5 isozymes. In vitro studies indicate that immediate-release topiramate is a mild inhibitor of CYP2C19 and a mild inducer of CYP3A4. The same drug interactions can be expected with the use of QUDEXY XR.

CNS Depressants And Alcohol

Topiramate is a CNS depressant. Concomitant administration of topiramate with other CNS depressant drugs or alcohol can result in significant CNS depression. Concomitant use of alcohol should be avoided [see WARNINGS AND PRECAUTIONS and CLINICAL PHARMACOLOGY].

Other Carbonic Anhydrase Inhibitors

Concomitant use of topiramate, a carbonic anhydrase inhibitor, with any other carbonic anhydrase inhibitor (e.g., zonisamide, acetazolamide or dichlorphenamide), may increase the severity of metabolic acidosis and may also increase the risk of kidney stone formation. Patients should be monitored for the appearance or worsening of metabolic acidosis when QUDEXY XR is given concomitantly with another carbonic anhydrase inhibitor [see CLINICAL PHARMACOLOGY].

Metformin

Topiramate treatment can frequently cause metabolic acidosis, a condition for which the use of metformin is contraindicated. The concomitant use of QUDEXY XR and metformin is contraindicated in patients with metabolic acidosis [see CONTRAINDICATIONS, WARNINGS AND PRECAUTIONS and CLINICAL PHARMACOLOGY].

Lithium

In patients, there was an observed increase in systemic exposure of lithium following topiramate doses of up to 600 mg per day. Lithium levels should be monitored when co-administered with high-dose QUDEXY XR [see CLINICAL PHARMACOLOGY].

Drug Abuse And Dependence

Controlled Substance

QUDEXY XR (topiramate) extended-release capsule is not a controlled substance.

Abuse

The abuse and dependence potential of QUDEXY XR has not been evaluated in human studies.

Dependence

QUDEXY XR has not been systematically studied in animals or humans for its potential for tolerance or physical dependence.

Last reviewed on RxList: 3/28/2014
This monograph has been modified to include the generic and brand name in many instances.

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