Amitriptyline HCl is 3-(10,11-dihydro-5H-dibenzo [a,d] cycloheptene-5-ylidene)-N,N-dimethyl-1-propanamine hydrochloride. Its empirical formula is C₂₀H₂₃N·HCl.

Amitriptyline HCl, a dibenzocycloheptadiene derivative, has a molecular weight of 313.87. It is a white, odorless, crystalline compound which is freely soluble in water.

Elavil (amitriptyline HCl) is supplied as 10 mg, 25 mg, 50 mg, 75 mg, 100 mg, and 150 mg tablets and as a sterile solution for intramuscular use. Inactive ingredients of the tablets are calcium phosphate, cellulose, colloidal silicon dioxide, hydroxypropyl cellulose, hydroxypropyl methylcellulose, lactose, magnesium stearate, starch, stearic acid, talc, and titanium dioxide. 10 mg amitriptyline HCl tablets also contain FD&C Blue 1. 25 mg amitriptyline HCl tablets also contain D&C Yellow 10, FD&C Blue 1, and FD&C Yellow 6. 50 mg amitriptyline HCl tablets also contain D&C Yellow 10, FD&C Yellow 6 and iron oxide. 75 mg amitriptyline HCl tablets also contain FD&C Yellow 6. 100 mg amitriptyline HCl tablets also contain FD&C Blue 2 and FD&C Red 40. 150 mg amitriptyline HCl tablets also contain FD&C Blue 2 and FD&C Yellow 6.

Each Milliliter of the Sterile Solution Contains: Amitriptyline hydrochloride: 10 mg; Dextrose: 44 mg; Water for Injection, q.s.:1 ml

Added as Preservatives: Methylparaben: 1.5 mg; Propylparaben: 0.2 mg

Last updated on RxList: 12/8/2004

For the relief of symptoms of depression. Endogenous depression is more likely to be alleviated than are other depressive states.

Oral Dosage

Dosage should be initiated at a low level and increased gradually, noting carefully the clinical response and any evidence of intolerance.

Initial Dosage for Adults: For outpatients 75 mg of amitriptyline HCl a day in divided doses is usually satisfactory. If necessary, this may be increased to a total of 150 mg per day. Increases are made preferably in the late afternoon and/or bedtime doses. A sedative effect may be apparent before the antidepressant effect is noted, but an adequate therapeutic effect may take as long as 30 days to develop.

An alternate method of initiating therapy in outpatients is to begin with 50 to 100 mg amitriptyline HCl at bedtime. This may be increased by 25 or 50 mg as necessary in the bedtime dose to a total of 150 mg per day.

Hospitalized patients may require 100 mg a day initially. This can be increased gradually to 200 mg a day if necessary. A small number of hospitalized patients may need as much as 300 mg a day.

Adolescent and Elderly Patients: In general, lower dosages are recommended for these patients. Ten mg 3 times a day with 20 mg at bedtime may be satisfactory in adolescent and elderly patients who do not tolerate higher dosages.

Maintenance: The usual maintenance dosage of amitriptyline HCl is 50 to 100 mg per day. In some patients 40 mg per day is sufficient. For maintenance therapy the total daily dosage may be given in a single dose preferably at bedtime. When satisfactory improvement has been reached, dosage should be reduced to the lowest amount that will maintain relief of symptoms. It is appropriate to continue maintenance therapy 3 months or longer to lessen the possibility of relapse.

Intramuscular Dosage

Initially, 20 to 30 mg (2 to 3 ml) four times a day.

When amitriptyline HCl injection is administered intramuscularly, the effects may appear more rapidly than with oral administration.

When amitriptyline HCl injection is used for initial therapy in patients unable or unwilling to take amitriptyline HCl tablets, the tablets should replace the injection as soon as possible.

Usage in Pediatric Patients: In view of the lack of experience with the use of this drug in children, it is not recommended at the present time for patients under 12 years of age.

Plasma Levels: Because of the wide variation in the absorption and distribution of tricyclic antidepressants in body fluids, it is difficult to directly correlate plasma levels and therapeutic effect. However, determination of plasma levels may be useful in identifying patients who appear to have toxic effects and may have excessively high levels, or those in whom lack of absorption or noncompliance is suspected. Adjustments in dosage should be made according to the patient's clinical response and not on the basis of plasma levels.¹⁴

Tablets:

Elavil, 10 mg, are blue, round, film coated tablets, identified with "40" debossed on one side and "Elavil" on the other side.
Elavil, 25 mg, are yellow, round, film coated tablets, identified with "45" debossed on one side and "Elavil" on the other side.
Elavil, 50 mg, are beige, round, film coated tablets, identified with "41" debossed on one side and "Elavil" on the other side.
Elavil, 75 mg, are orange, round, film coated tablets, identified with "42" debossed on one side and "Elavil" on the other side.
Elavil, 100 mg, are mauve, round, film coated tablets, identified with "43" debossed on one side and "Elavil" on the other side.
Elavil, 150 mg, are blue, capsule shaped, film coated tablets, identified with "47" debossed on one side and "Elavil" on the other side.

Injection:

Elavil, 10 mg/ml, is a clear, colorless solution, and is supplied in 10 ml vials:

Storage: Store amitriptyline HCl tablets in a well-closed container. Avoid storage at temperatures above 30°C (86°F). In addition, amitriptyline HCl tablets 10 mg must be protected from light and stored in a well-closed, light-resistant container.

Protect amitriptyline HCl injection from freezing and avoid storage above 30°C (86°F).

REFERENCES

1. Ayd FJ Jr: Amitriptyline therapy for depressive reactions. Psychosomatics 1960;1:320-325.
2. Diamond S: Human metabolizer of amitriptyline tagged with carbon 14. Curr Ther Res, Mar 1965, pp 170-175.
3. Dorfman W: Clinical experiences with amitriptyline: A preliminary report. Psychosomatics 1960;1:153-155.
4. Fallette JM, Stasney CR, Mintz AA: Amitriptyline poisoning treated with physostigmine. South Med J 1970;63:1492-1493.
5. Hollister LE, Overall JE, Johnson M, et al: Controlled comparison of amitriptyline, imipramine and placebo in hospitalized depressed patients. J Nerv Ment Dis 1964;139:370-375.
6. Hordern A, Burt CG, Holt NF: Depressive states: A pharmacotherapeutic study, Springfield study. Springfield, III, Charles C. Thomas, 1965.
7. Jenike MA: Treatment of Affective Illness in the Elderly with Drugs and Electroconvulsive Therapy. J Geriatr Psychiatry 1989;22(1):77-112.
8. Klerman GL, Cole JO: Clinical pharmacology of imipramine and related antidepressant compounds. Int J Psychiatry 1976;3:267-304.
9. Liu B, Anderson G, Mittman N, et al: Use of selective serotonin-reuptake inhibitors or tricyclic antidepressants and risk of hip fractures in elderly people. Lancet 1998;351(9112):1303-1307.
10. McConaghy N, Joffe AD, Kingston WR, et al: Correlation of clinical features of depressed outpatients with response to amitriptyline and protriptyline. Br J Psychiatry 1968;114:103-106.
11. McDonald IM, Perkins M, Marjerrison G, et al: A controlled comparison of amitriptyline and electroconvulsive therapy in the treatment of depression. Am J Psychiatry 1966;122:1427-1431.
12. Slovis T, Ott J, Teitelbaum, et al: Physostigmine therapy in acute tricyclic antidepressant poisoning. Clin Toxicol 1971;4:451-459.
13. Symposium on depression with special studies of a new antidepressant, amitriptyline. Dis Nerv Syst, (Sect 2) May 1961, pp 5-56.
14. Hollister LE: JAMA 1979;241:2350-2533.

Last updated on RxList: 12/8/2004

Within each category the following adverse reactions are listed in order of decreasing severity. Included in the listing are a few adverse reactions which have not been reported with this specific drug. However, pharmacological similarities among the tricyclic antidepressant drugs require that each of the reactions be considered when amitriptyline is administered.

Cardiovascular: Myocardial infarction; stroke; nonspecific ECG changes and changes in AV conduction; heart block; arrhythmias; hypotension, particularly orthostatic hypotension; syncope; hypertension; tachycardia; palpitation.

CNS and Neuromuscular: Coma; seizures; hallucinations; delusions; confusional states; disorientation; incoordination; ataxia; tremors; peripheral neuropathy; numbness, tingling, and paresthesias of the extremities; extrapyramidal symptoms including abnormal involuntary movements and tardive dyskinesia; dysarthria; disturbed concentration; excitement; anxiety; insomnia; restlessness; nightmares; drowsiness; dizziness; weakness; fatigue; headache; syndrome of inappropriate ADH (antidiuretic hormone) secretion; tinnitus; alteration in EEG patterns.

Anticholinergic: Paralytic ileus; hyperpyrexia; urinary retention; dilatation of the urinary tract; constipation; blurred vision, disturbance of accommodation, increased ocular pressure, mydriasis; dry mouth.

Allergic: Skin rash; urticaria; photosensitization; edema of face and tongue.

Hematologic: Bone marrow depression including agranulocytosis, leukopenia, thrombocytopenia; purpura; eosinophilia.

Gastrointestinal: Rarely hepatitis (including altered liver function and jaundice); nausea; epigastric distress; vomiting; anorexia; stomatitis; peculiar taste; diarrhea; parotid swelling; black tongue.

Endocrine: Testicular swelling and gynecomastia in the male; breast enlargement and galactorrhea in the female; increased or decreased libido; impotence; elevation and lowering of blood sugar levels.

Other: Alopecia; edema; weight gain or loss; urinary frequency; increased perspiration.

Withdrawal Symptoms: After prolonged administration, abrupt cessation of treatment may produce nausea, headache, and malaise. Gradual dosage reduction has been reported to produce, within two weeks, transient symptoms including irritability, restlessness, and dream and sleep disturbance.

These symptoms are not indicative of addiction. Rare instances have been reported of mania or hypomania occurring within 2-7 days following cessation of chronic therapy with tricyclic antidepressants.

Causal Relationship Unknown: Other reactions, reported under circumstances where a causal relationship could not be established, are listed to serve as alerting information to physicians:

Body as a Whole: Lupus-like syndrome (migratory arthritis, positive ANA and rheumatoid factor).

Digestive: Hepatic failure, ageusia.

Drugs Metabolized by P450 2D6 ¾ The biochemical activity of the drug metabolizing isozyme cytochrome P450 2D6 (debrisoquin hydroxylase) is reduced in a subset of the caucasian population (about 7-10% of caucasians are so called "poor metabolizers"); reliable estimates of the prevalence of reduced P450 2D6 isozyme activity among Asian, African and other populations are not yet available. Poor metabolizers have higher than expected plasma concentrations of tricyclic antidepressants (TCAs) when given usual doses. Depending on the fraction of drug metabolized by P450 2D6, the increase in plasma concentration may be small, or quite large (8-fold increase in plasma AUC of the TCA).

In addition, certain drugs inhibit the activity of this isozyme and make normal metabolizers resemble poor metabolizers. An individual who is stable on a given dose of TCA may become abruptly toxic when given one of these inhibiting drugs as concomitant therapy. The drugs that inhibit cytochrome P450 2D6 include some that are not metabolized by the enzyme (quinidine; cimetidine) and many that are substrates for P450 2D6 (many other antidepressants, phenothiazines, and the Type 1C antiarrhythmics propafenone and flecainide). While all the selective serotonin reuptake inhibitors (SSRIs), e.g., fluoxetine, sertraline, and paroxetine, inhibit P450 2D6, they may vary in the extent of inhibition. The extent to which SSRI-TCA interactions may pose clinical problems will depend on the degree of inhibition and the pharmacokinetics of the SSRI involved. Nevertheless, caution is indicated in the coadministration of TCAs with any of the SSRIs and also in switching from one class to the other. Of particular importance, sufficient time must elapse before initiating TCA treatment in a patient being withdrawn from fluoxetine, given the long half-life of the parent and active metabolite (at least 5 weeks may be necessary).

Concomitant use of tricyclic antidepressants with drugs that can inhibit cytochrome P450 2D6 may require lower doses than usually prescribed for either the tricyclic antidepressant or the other drug. Furthermore, whenever one of these other drugs is withdrawn from co-therapy, an increased dose of tricyclic antidepressant may be required. It is desirable to monitor TCA plasma levels whenever a TCA is going to be coadministered with another drug known to be an inhibitor of P450 2D6.

Monoamine Oxidase Inhibitors: (See CONTRAINDICATIONS.) Guanethidine or similarly acting compounds; thyroid medication; alcohol, barbiturates and other CNS depressants; and disulfiram (see WARNINGS.)

When amitriptyline HCl is given with anticholinergic agents or sympathomimetic drugs, including epinephrine combined with local anesthetics, close supervision and careful adjustment of dosages are required.

Hyperpyrexia has been reported when amitriptyline HCl is administered with anticholinergic agents or with neuroleptic drugs, particularly during hot weather.

Paralytic ileus may occur in patients taking tricyclic antidepressants in combination with anticholinergic-type drugs.

Cimetidine is reported to reduce hepatic metabolism of certain tricyclic antidepressants, thereby delaying elimination and increasing steady-state concentrations of these drugs. Clinically significant effects have been reported with the tricyclic antidepressants when used concomitantly with cimetidine. Increases in plasma levels of tricyclic antidepressants, and in the frequency and severity of side effects, particularly anticholinergic, have been reported when cimetidine was added to the drug regimen. Discontinuation of cimetidine in well-controlled patients receiving tricyclic antidepressants and cimetidine may decrease the plasma levels and efficacy of the antidepressants.

Caution is advised if patients receive large doses of ethchlorvynol concurrently. Transient delirium has been reported in patients who were treated with one gram of ethchlorvynol and 75 - 150 mg of amitriptyline HCl.

Last updated on RxList: 12/8/2004

Clinical Worsening and Suicide Risk

Patients with major depressive disorder (MDD), both adult and pediatric, may experience worsening of their depression and/or the emergence of suicidal ideation and behavior (suicidality) or unusual changes in behavior, whether or not they are taking antidepressant medications, and this risk may persist until significant remission occurs. Suicide is a known risk of depression and certain other psychiatric disorders, and these disorders themselves are the strongest predictors of suicide. There has been a long-standing concern, however, that antidepressants may have a role in inducing worsening of depression and the emergence of suicidality in certain patients during the early phases of treatment. Pooled analyses of short-term placebo-controlled trials of antidepressant drugs (SSRIs and others) showed that these drugs increase the risk of suicidal thinking and behavior (suicidality) in children, adolescents, and young adults (ages 18-24) with major depressive disorder (MDD) and other psychiatric disorders. Short-term studies did not show an increase in the risk of suicidality with antidepressants compared to placebo in adults beyond age 24; there was a reduction with antidepressants compared to placebo in adults aged 65 and older.

The pooled analyses of placebo-controlled trials in children and adolescents with MDD, obsessive compulsive disorder (OCD), or other psychiatric disorders included a total of 24 short-term trials of 9 antidepressant drugs in over 4400 patients. The pooled analyses of placebo-controlled trials in adults with MDD or other psychiatric disorders included a total of 295 short-term trials (median duration of 2 months) of 11 antidepressant drugs in over 77,000 patients. There was considerable variation in risk of suicidality among drugs, but a tendency toward an increase in the younger patients for almost all drugs studied. There were differences in absolute risk of suicidality across the different indications, with the highest incidence in MDD. The risk differences (drug vs placebo), however, were relatively stable within age strata and across indications. These risk differences (drug-placebo difference in the number of cases of suicidality per 1000 patients treated) are provided in Table 1.

Table 1

Age Range	Drug-Placebo Difference in Number of Cases of Suicidality per 1000 Patients Treated
	Increases Compared to Placebo
<18	14 additional cases
18-24	5 additional cases
	Decreases Compared to Placebo
25-64	1 fewer case
Age;65	6 fewer cases

No suicides occurred in any of the pediatric trials. There were suicides in the adult trials, but the number was not sufficient to reach any conclusion about drug effect on suicide.

It is unknown whether the suicidality risk extends to longer-term use, i.e., beyond several months. However, there is substantial evidence from placebo-controlled maintenance trials in adults with depression that the use of antidepressants can delay the recurrence of depression.

All patients being treated with antidepressants for any indication should be monitored appropriately and observed closely for clinical worsening, suicidality, and unusual changes in behavior, especially during the initial few months of a course of drug therapy, or at times of dose changes, either increases or decreases.

The following symptoms, anxiety, agitation, panic attacks, insomnia, irritability, hostility, aggressiveness, impulsivity, akathisia (psychomotor restlessness), hypomania, and mania, have been reported in adult and pediatric patients being treated with antidepressants for major depressive disorder as well as for other indications, both psychiatric and nonpsychiatric. Although a causal link between the emergence of such symptoms and either the worsening of depression and/or the emergence of suicidal impulses has not been established, there is concern that such symptoms may represent precursors to emerging suicidality.

Consideration should be given to changing the therapeutic regimen, including possibly discontinuing the medication, in patients whose depression is persistently worse, or who are experiencing emergent suicidality or symptoms that might be precursors to worsening depression or suicidality, especially if these symptoms are severe, abrupt in onset, or were not part of the patient's presenting symptoms.

Families and caregivers of patients being treated with antidepressants for major depressive disorder or other indications, both psychiatric and nonpsychiatric, should be alerted about the need to monitor patients for the emergence of agitation, irritability, unusual changes in behavior, and the other symptoms described above, as well as the emergence of suicidality, and to report such symptoms immediately to health care providers. Such monitoring should include daily observation by families and caregivers. Prescriptions for Amitriptyline hydrochloride should be written for the smallest quantity of tablets consistent with good patient management, in order to reduce the risk of overdose.

Screening Patients for Bipolar Disorder

A major depressive episode may be the initial presentation of bipolar disorder. It is generally believed (though not established in controlled trials) that treating such an episode with an antidepressant alone may increase the likelihood of precipitation of a mixed/manic episode in patients at risk for bipolar disorder. Whether any of the symptoms described above represent such a conversion is unknown. However, prior to initiating treatment with an antidepressant, patients with depressive symptoms should be adequately screened to determine if they are at risk for bipolar disorder; such screening should include a detailed psychiatric history, including a family history of suicide, bipolar disorder, and depression. It should be noted that Amitriptyline hydrochloride is not approved for use in treating bipolar depression.

Amitriptyline hydrochloride may block the antihypertensive action of guanethidine or similarly acting compounds.

It should be used with caution in patients with a history of seizures and, because of its atropine-like action, in patients with a history of urinary retention, angle-closure glaucoma or increased intraocular pressure. In patients with angle-closure glaucoma, even average doses may precipitate an attack.

Patients with cardiovascular disorders should be watched closely. Tricyclic antidepressant drugs, including Amitriptyline hydrochloride, particularly when given in high doses, have been reported to produce arrhythmias, sinus tachycardia, and prolongation of the conduction time. Myocardial infarction and stroke have been reported with drugs of this class.

Close supervision is required when Amitriptyline hydrochloride is given to hyperthyroid patients or those receiving thyroid medication.

Amitriptyline may enhance the response to alcohol and the effects of barbiturates and other CNS depressants. In patients who may use alcohol excessively, it should be borne in mind that the potentiation may increase the danger inherent in any suicide attempt or overdosage. Delirium has been reported with concurrent administration of Amitriptyline and disulfiram.

Usage in Pregnancy

Pregnancy Category C

Teratogenic effects were not observed in mice, rats, or rabbits when amitriptyline was given orally at doses of 2 to 40 mg/kg/day (up to 13 times the maximum recommended human amitriptyline dose of 150 mg/day or 3 mg/kg/day for a 50 kg patient). Studies in literature have shown amitriptyline to be teratogenic in mice and hamsters when given by various routes of administration at doses of 28 to 100 mg/kg/day (9 to 33 times the maximum recommended human dose), producing multiple malformations. Another study in the rat reported that an oral dose of 25 mg/kg/day (8 times the maximum recommended human dose) produced delays in ossification of fetal vertebral bodies without other signs of embryotoxicity. In rabbits, an oral dose of 60 mg/kg/day (20 times the maximum recommended human dose) was reported to cause incomplete ossification of the cranial bones.

Amitriptyline has been shown to cross the placenta. Although a causal relationship has not been established, there have been a few reports of adverse events, including CNS effects, limb deformities, or developmental delay, in infants whose mothers had taken amitriptyline during pregnancy.

There are no adequate and well-controlled studies in pregnant women. Amitriptyline HCl should be used during pregnancy only if the potential benefit to the mother justifies the potential risk to the fetus.

Nursing Mothers

Amitriptyline is excreted into breast milk. In one report in which a patient received amitriptyline 100 mg/day while nursing her infant, levels of 83 - 141 ng/ml were detected in the mother's serum. Levels of 135 - 151 ng/ml were found in the breast milk, but no trace of the drug could be detected in the infant's serum.

Because of the potential for serious adverse reactions in nursing infants from amitriptyline, a decision should be made whether to discontinue nursing or to discontinue the drug, taking into account the importance of the drug to the mother.

Use in Pediatric Patients

In view of the lack of experience with the use of this drug in children, it is not recommended at the present time for patients under 12 years of age.

Schizophrenic patients may develop increased symptoms of psychosis; patients with paranoid symptomatology may have an exaggeration of such symptoms. Depressed patients, particularly those with known manic-depressive illness, may experience a shift to mania or hypomania. In these circumstances the dose of amitriptyline may be reduced or a major tranquilizer such as perphenazine may be administered concurrently.

The possibility of suicide in depressed patients remains until significant remission occurs. Potentially suicidal patients should not have access to large quantities of this drug. Prescriptions should be written for the smallest amount feasible.

Concurrent administration of amitriptyline HCl and electroshock therapy may increase the hazards associated with such therapy. Such treatment should be limited to patients for whom it is essential.

When possible, the drug should be discontinued several days before elective surgery.

Both elevation and lowering of blood sugar levels have been reported.

Amitriptyline HCl should be used with caution in patients with impaired liver function.

Information for the Patients: Prescribers or other health professionals should inform patients, their families, and their caregivers about the benefits and risks associated with treatment with Amitriptyline hydrochloride and should counsel them in its appropriate use. A patient Medication Guide about "Antidepressant Medicines, Depression and other Serious Mental Illnesses, and Suicidal Thoughts or Actions" is available for Amitriptyline hydrochloride. The prescriber or health professional should instruct patients, their families, and their caregivers to read the Medication Guide and should assist them in understanding its contents. Patients should be given the opportunity to discuss the contents of the Medication Guide and to obtain answers to any questions they may have. The complete text of the Medication Guide is reprinted at the end of this document.

Patients should be advised of the following issues and asked to alert their prescriber if these occur while taking Amitriptyline hydrochloride.

Clinical Worsening and Suicide Risk: Patients, their families, and their caregivers should be encouraged to be alert to the emergence of anxiety, agitation, panic attacks, insomnia, irritability, hostility, aggressiveness, impulsivity, akathisia (psychomotor restlessness), hypomania, mania, other unusual changes in behavior, worsening of depression, and suicidal ideation, especially early during antidepressant treatment and when the dose is adjusted up or down. Families and caregivers of patients should be advised to look for the emergence of such symptoms on a day-to-day basis, since changes may be abrupt. Such symptoms should be reported to the patient's prescriber or health professional, especially if they are severe, abrupt in onset, or were not part of the patient's presenting symptoms. Symptoms such as these may be associated with an increased risk for suicidal thinking and behavior and indicate a need for very close monitoring and possibly changes in the medication.

While on therapy with Amitriptyline hydrochloride, patients should be advised as to the possible impairment of mental and/or physical abilities required for performance of hazardous tasks, such as operating machinery or driving a motor vehicle.

Geriatric Use: Clinical experience has not identified differences in responses between elderly and younger patients. In general, dose election for an elderly patient should be cautious, usually starting at the low end of the dosing range, reflecting the greater frequency of decreased hepatic function, concomitant disease and other drug therapy in elderly patients.

Geriatric patients are particularly sensitive to the anticholinergic side effects of tricyclic antidepressants including amitriptyline HCl. Peripheral anticholinergic effects include tachycardia, urinary retention, constipation, dry mouth, blurred vision, and exacerbation of narrow-angle glaucoma. Central nervous system anticholinergic effects include cognitive impairment, psychomotor slowing, confusion, sedation, and delirium. Elderly patients taking amitriptyline HCl may be at increased risk for falls. Elderly patients should be started on low doses of amitriptyline HCl and observed closely (see DOSAGE AND ADMINISTRATION).

Pediatric Use: Safety and effectiveness in the pediatric population have not been established (see BOX WARNING and WARNINGS: Clinical Worsening and Suicide Risk). Anyone considering the use of Amitriptyline in a child or adolescent must balance the potential risks with the clinical need.

Last updated on RxList: 12/8/2004

Deaths may occur from overdosage with this class of drugs. Multiple drug ingestion (including alcohol) is common in deliberate tricyclic antidepressant overdose. As the management is complex and changing, it is recommended that the physician contact a poison control center for current information on treatment. Signs and symptoms of toxicity develop rapidly after tricyclic antidepressant overdose; therefore, hospital monitoring is required as soon as possible.

Manifestations

Critical manifestations of overdose include: cardiac dysrhythmias, severe hypotension, convulsions, and CNS depression, including coma. Changes in the electrocardiogram, particularly in QRS axis or width, are clinically significant indictors of tricyclic antidepressant toxicity.

Other signs of overdose may include: impaired myocardial contractility, confusion, disturbed concentration, transient visual hallucinations, dilated pupils, disorders of ocular motility, agitation, hyperactive reflexes, polyradiculoneuropathy, stupor, drowsiness, muscle rigidity, vomiting, hypothermia, hyperpyrexia, or any of the symptoms listed under ADVERSE REACTIONS.

Management

General: Obtain an ECG and immediately initiate cardiac monitoring. Protect the patient's airway, establish and intravenous line, and initiate gastric decontamination. A minimum of 6 hours of observation with cardiac monitoring and observation for signs of CNS or respiratory depression, hypotension, cardiac dysrhythmias and/or conduction blocks, and seizures is necessary. If signs of toxicity occur at any time during this period, extended monitoring is required. There are case reports of patients succumbing to fatal dysrhythmias late after overdose; these patients had clinical evidence of significant poisoning prior to death, and most received inadequate gastrointestinal decontamination. Monitoring of plasma drug levels should not guide management of the patient.

Gastrointestinal Decontamination: All patients suspected of tricyclic antidepressant overdose should receive gastrointestinal decontamination. This should include large volume gastric lavage followed by activated charcoal. If consciousness is impared, the airway should be secured prior to lavage. Emesis is contraindicated.

Cardiovascular: A maximal limb-lead QRS duration of ≥0.10 seconds may be the best indication of the severity of the overdose. Intravenous sodium bicarbonate should be used to maintain the serum pH in the range of 7.45-7.55. If the pH response is inadequate, hyperventilation may also be used. Concomitant use of hyperventilation and sodium bicarbonate should be done with extreme caution, with frequent pH monitoring. A pH >7.60 or a pCO₂ <20 mmHg is undesirable. Dysrhythmias unresponsive to sodium bicarbonate therapy/hyperventilation may respond to lidocaine, bretylium or phenytoin. Type IA and IC antiarrhythmics are generally contraindicated (e.g., quinidine, disopyramide, and procainamide).

In rare instances, hemoperfusion may be beneficial in acute refractory cardiovascular instability in patients with acute toxicity. However, hemodialysis, peritoneal dialysis, exchange transfusions, and forced diuresis generally have been reported as ineffective in tricyclic antidepressant poisoning.

CNS: In patients with CNS depression, early intubation is advised because of the potential for abrupt deterioration. Seizures should be controlled with benzodiazepines, or if these are ineffective other anticonvulsants (e.g., phenobarbital, phenytoin). Physostigmine is not recommended except to treat life-threatening symptoms that have been unresponsive to other therapies, and then only in consultation with a poison control center.

Psychiatric Follow-up: Since overdosage is often deliberate, patients may attempt suicide by other means during the recovery phase. Psychiatric referral may be appropriate.

Pediatric Management: The principles of management of pediatric and adult overdosages are similiar. It is strongly recommended that the physician contact the local poison control center for specific pediatric treatment.

Amitriptyline HCl is contraindicated in patients who have shown prior hypersensitivity to it.

It should not be given concomitantly with monoamine oxidase inhibitors. Hyperpyretic crises, severe convulsions, and deaths have occurred in patients receiving tricyclic antidepressant and monoamine oxidase inhibiting drugs simultaneously. When it is desired to replace a monoamine oxidase inhibitor with amitriptyline HCl, a minimum of 14 days should be allowed to elapse after the former is discontinued. Amitriptyline HCl should then be initiated cautiously with gradual increase in dosage until optimum response is achieved.

This drug is not recommended for use during the acute recovery phase following myocardial infarction.

Last updated on RxList: 12/8/2004

Amitriptyline HCl is an antidepressant with sedative effects. Its mechanism of action in man is not known. It is not a monoamine oxidase inhibitor and it does not act primarily by stimulation of the central nervous system.

Amitriptyline inhibits the membrane pump mechanism responsible for uptake of norepinephrine and serotonin in adrenergic and serotonergic neurons. Pharmacologically this action may potentiate or prolong neuronal activity since reuptake of these biogenic amines is important physiologically in terminating transmitting activity. This interference with the reuptake of norepinephrine and/or serotonin is believed by some to underlie the antidepressant activity of amitriptyline.

Metabolism

Studies in man following oral administration of ¹⁴C-labeled drug indicated that amitriptyline is rapidly absorbed and metabolized. Radioactivity of the plasma was practically negligible, although significant amounts of radioactivity appeared in the urine by 4 to 6 hours and one-half to one-third of the drug was excreted within 24 hours.

Amitriptyline is metabolized by N-demethylation and bridge hydroxylation in man, rabbit, and rat. Virtually the entire dose is excreted as glucuronide or sulfate conjugate of metabolites, with little unchanged drug appearing in the urine. Other metabolic pathways may be involved.

Last updated on RxList: 12/8/2004

Please see WARNINGS and PRECAUTIONS.

While on therapy with amitriptyline HCl, patients should be advised as to the possible impairment of mental and/or physical abilities required for performance of hazardous tasks, such as operating machinery or driving a motor vehicle.

Last updated on RxList: 12/8/2004

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.

AMITRIPTYLINE - ORAL

(A-mi-TRIP-ti-leen)

WARNING: Antidepressant medications are used to treat a variety of conditions, including depression and other mental/mood disorders. These medications can help prevent suicidal thoughts/attempts and provide other important benefits. However, studies have shown that a small number of people (especially people younger than 25) who take antidepressants for any condition may experience worsening depression, other mental/mood symptoms, or suicidal thoughts/attempts. Therefore, it is very important to talk with the doctor about the risks and benefits of antidepressant medication (especially for people younger than 25), even if treatment is not for a mental/mood condition. Tell the doctor immediately if you notice worsening depression/other psychiatric conditions, unusual behavior changes (including possible suicidal thoughts/attempts), or other mental/mood changes (including new/worsening anxiety, panic attacks, trouble sleeping, irritability, hostile/angry feelings, impulsive actions, severe restlessness, very rapid speech). Be especially watchful for these symptoms when a new antidepressant is started or when the dose is changed.

USES: This medication is used to treat mental/mood problems such as depression. It may help improve mood and feelings of well-being, relieve anxiety and tension, help you sleep better, and increase your energy level. This medication belongs to a class of medications called tricyclic antidepressants. It works by affecting the balance of certain natural chemicals (neurotransmitters) in the brain.

OTHER USES: This section contains uses of this drug that are not listed in the approved professional labeling for the drug but that may be prescribed by your health care professional. Use this drug for a condition that is listed in this section only if it has been so prescribed by your health care professional.

This medication may also be used to treat other mental/mood problems (e.g., anxiety, bipolar disorder), certain types of pain (e.g., peripheral neuropathy, neuropathic pain), eating disorders (e.g., bulimia), and trouble sleeping, or to prevent migraine headache.

HOW TO USE: Read the Medication Guide available from your pharmacist. Consult your doctor or pharmacist if you have any questions.

Take this medication by mouth, usually 1 to 3 times daily or as directed by your doctor. If you take it only once a day, take it at bedtime to help reduce daytime sleepiness. The dosage is based on your age, medical condition and response to therapy. Your doctor may start you at a low dose and gradually increase your dose over several weeks. Follow your doctor's instructions carefully.

This medication does not work right away. It may take up to 2 to 3 weeks before you experience the full benefits.

Use this medication regularly in order to get the most benefit from it. To help you remember, take it at the same times each day.

It is important to continue taking this medication even if you feel well. Do not suddenly stop taking this medication without consulting your doctor. Some conditions may become worse when the drug is abruptly stopped. Muscle aches, headaches and worsening anxiety may also occur. Your dose may need to be gradually decreased.

Tell your doctor if your condition persists or worsens (e.g., your feelings of sadness get worse, or you have thoughts of suicide).

SIDE EFFECTS: See also Warning section.

Drowsiness, dizziness, dry mouth, blurred vision, constipation, fast heartbeat, nausea, vomiting, loss of appetite, changes in taste, weight gain, tiredness, or trouble urinating may occur. If any of these effects persist or worsen, notify your doctor or pharmacist promptly.

To relieve dry mouth, suck on (sugarless) hard candy or ice chips, chew (sugarless) gum, drink water, or use a saliva substitute.

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.

Tell your doctor immediately if any of these unlikely but serious side effects occur: persistent heartburn, confusion, mental/mood changes (e.g., agitation, excitement), loss of coordination, shaking, restlessness, uncontrollable movements of the mouth/face/hands, fast/irregular heartbeat, numbness/tingling of the hands/feet, decreased sexual ability/desire, enlarged/painful breasts, ringing in the ears, nervousness, sweating, unusual hunger, increased thirst/urination, fainting, muscle weakness/spasms, severe vomiting, severe constipation, swelling of the hands/feet.

Tell your doctor immediately if any of these rare but very serious side effects occur: seizures, easy bruising/bleeding, signs of infection (e.g., fever, persistent sore throat), yellowing eyes/skin, severe stomach/abdominal pain, dark urine, persistent nausea/vomiting, pain/redness/swelling of arms or legs.

Seek immediate medical attention if any of these rare but very serious side effects occur: weakness on one side of the body, slurred speech, vision changes.

A very serious allergic reaction to this drug is unlikely, but seek immediate medical attention if it occurs. Symptoms of a serious allergic reaction may include: rash, itching, swelling, 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: See also Warning section.

Before taking amitriptyline, tell your doctor or pharmacist if you are allergic to it, or to other tricyclic antidepressants (e.g., nortriptyline), or if you have any other allergies.

This medication should not be used if you have certain medical conditions. Before using this medicine, consult your doctor or pharmacist if you have: a certain eye problem (untreated narrow-angle glaucoma), a heart attack in the last 30 days.

Before using this medication, tell your doctor or pharmacist your medical history, especially of: diabetes, kidney problems, liver problems, heart problems (e.g., QT prolongation in the EKG), problems urinating (e.g., due to enlarged prostate), eating disorders (e.g., bulimia), overactive thyroid (hyperthyroidism), long-term lung problems (e.g., pulmonary insufficiency), a certain eye problem (open-angle glaucoma), personal or family history of mental/mood conditions (e.g., bipolar disorder, psychosis), family history of suicide, seizures, conditions that may increase your risk of seizures (e.g., other brain disease, alcohol withdrawal).

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

To minimize dizziness and the risk of fainting, get up slowly when rising from a sitting or lying position.

Before having surgery, tell your doctor or dentist that you are taking this medication.

This medication may make you more sensitive to the sun. Avoid prolonged sun exposure, tanning booths, and sunlamps. Wear sunblock (SPF 30 or greater) and a hat when outdoors.

If you have diabetes, this drug may increase your blood sugar levels. Check your blood sugar levels regularly as directed by your doctor. Tell your doctor immediately if you have symptoms such as increased thirst/urination, shakiness, unusual sweating, or hunger. Your anti-diabetic medication or diet may need to be adjusted.

Depression can lead to thoughts/attempts of suicide. Tell your doctor immediately if you have any suicidal thoughts, worsening depression, or any other mental/mood changes (including new or worsening anxiety, agitation, panic attacks, trouble sleeping, irritability, hostile/angry feelings, impulsive actions, severe restlessness, rapid speech). Keep all medical appointments so your doctor can monitor your progress closely and adjust your medication if needed.

Caution is advised when using this drug in the elderly because they may be more sensitive to its side effects, especially dizziness, drowsiness, confusion, and difficulty urinating.

Caution is advised when using this drug in children. (See also Warning section.)

This medication should be used only when clearly needed during pregnancy. Discuss the risks and benefits with your doctor.

This medication passes into breast milk and may have undesirable effects on a nursing infant. Breast-feeding while using this drug is not recommended. Consult your doctor before breast-feeding.

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

This drug should not be used with the following medications because very serious (possibly fatal) interactions may occur: arbutamine, sibutramine, iomeprol, lumefantrine, MAO inhibitors (e.g., furazolidone, isocarboxazid, linezolid, moclobemide, phenelzine, procarbazine, selegiline, tranylcypromine).

Avoid taking MAO inhibitors within 2 weeks before and after treatment with this medication. In some cases a serious, possibly fatal drug interaction may occur.

If you are currently using any of these medications listed above, tell your doctor or pharmacist before starting amitriptyline.

Other drugs besides amitriptyline that may affect the heart rhythm (QT prolongation in the EKG) include pimozide, cisapride, halofantrine, disopyramide, grepafloxacin and sparfloxacin, among others. Before using this drug, report all medications you are currently using to your doctor or pharmacist. QT prolongation can infrequently result in serious (rarely fatal) fast/irregular heartbeat and other symptoms (e.g., severe dizziness, fainting) that require immediate medical attention. Ask your doctor or pharmacist for more details and for instructions on how you may reduce the risk of this effect.

Before using this medication, tell your doctor or pharmacist of all prescription and nonprescription/herbal products you may use, especially of: alcohol, amprenavir/fosamprenavir, duloxetine, clonidine, ethchlorvynol, fluconazole, guanadrel, guanethidine, levodopa, warfarin, barbiturates (e.g., phenobarbital), cimetidine, drugs for heart rhythm (e.g., flecainide, propafenone, quinidine), phenothiazines (e.g., chlorpromazine), SSRI antidepressants (e.g., citalopram, fluvoxamine, sertraline, fluoxetine), stimulants (e.g., amphetamines, methylphenidate), certain sympathomimetics (e.g., albuterol, epinephrine, phenylephrine), St John's wort, terbinafine, reserpine, thyroid supplements, disulfiram.

If you have been taking fluoxetine, wait at least 5 weeks before starting amitriptyline.

Cigarette smoking decreases blood levels of this medication. Tell your doctor if you smoke or if you have recently stopped smoking.

Tell your doctor or pharmacist if you also take drugs that cause drowsiness such as: certain antihistamines (e.g., diphenhydramine), anti-seizure drugs (e.g., phenytoin, carbamazepine), medicine for sleep or anxiety (e.g., alprazolam, diazepam, zolpidem), muscle relaxants, narcotic pain relievers (e.g., codeine), psychiatric medicines (e.g., fluphenazine, risperidone, trazodone).

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

Also report the use of drugs which might increase seizure risk (decrease seizure threshold) when combined with amitriptyline (e.g., bupropion, isoniazid (INH), theophylline, tramadol, among others).

Consult your doctor or pharmacist for details.

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. Symptoms of overdose may include: severe dizziness, hallucinations, fast/irregular heartbeat, fainting, widened pupils, muscle stiffness, seizures.

NOTES: Do not share this medication with others.

Laboratory and/or medical tests (e.g., kidney function, amitriptyline blood level) may be performed from time to time to monitor your progress or check for side effects. Keep all medical appointments. Consult your doctor for more details.

MISSED DOSE: If you miss a dose, take 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 between 59-86 degrees F (15-30 degrees C) away from light and moisture. 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.