Amitriptyline 
Brand name (Elavil and Endep)

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Overdose   Back to top of page

In patients with glaucoma, even average doses may precipitate an attack.

Treatment:
Treatment is symptomatic and supportive. Cardiac arrhythmias and CNS involvement pose the greatest threat and may occur suddenly even when initial symptoms appear to be mild. Therefore, patients who may have ingested an overdosage of amitriptyline, particularly children, should be hospitalized and kept under close surveillance. Induced emesis and gastric lavage are recommended in the alert and conscious patient. Following gastric lavage, activated charcoal may be administered. Twenty to 30 g of activated charcoal may be given every 4 to 6 hours during the first 24 to 48 hours after ingestion. It may be helpful to leave the tube in the stomach, with irrigation (with an electrolyte balanced fluid) and continual aspiration of stomach contents possibly promoting more rapid elimination of the drug from the body. If the patient is not alert, a cuffed endotracheal tube should be inserted before lavage is performed, and emesis should not be induced. An open airway should be maintained. Standard measures (oxygen, i.v. fluids, corticosteroids) may be used to manage circulatory shock and metabolic acidosis. Norepinephrine or other pressor agents (but no epinephrine) by i.v. drop infusion under continuous monitoring may be used if necessary. Failing respiration must be maintained by artificial means, but respiratory stimulants should not be used. Regulate body temperature. Hyperpyrexia should be controlled by external measures, such as ice packs and cooling sponge baths. Catheterization should be performed in the unconscious patient. Continuous cardiac monitoring should be instituted in all patients, particularly in the presence of ECG abnormalities and should be maintained for several days after the cardiac rhythm has returned to normal. Because of its effects on cardiac conduction, digitalis should be used only with caution. If rapid digitalization is required for the treatment of congestive heart failure, special care should be exercised in using the drug.

It has been reported that i.v. administration of physostigmine salicylate may reverse some of the CNS and cardiovascular effects of tricyclic antidepressants. The dosage that has been recommended for adults is 1 to 2 mg in very slow i.v. injection. In children, the initial dosage should not exceed 0.5 mg and should be adjusted to age and response. Since physostigmine has a short duration of action, administration may have to be repeated at 30 to 60 minute intervals particularly in life-threatening signs such as arrhythmias, convulsions, and deep coma recur or persist after the initial dose of physostigmine. Because physostigmine itself may be toxic, it is not recommended for routine use.

The room should be darkened, with a minimal amount of external stimulation, to reduce the tendency to convulsions. If convulsions occur, they should preferably be controlled by non-barbiturate sedatives, such as chlordiazepoxide or diazepam, or by an inhalation anesthetic (amitriptyline increases the CNS depressant but not the anticonvulsant action of barbiturates). Deaths by deliberate or accidental overdosage have occurred with this class of drugs. Since the propensity for suicide is high in depressed patients, a suicide attempt by other means may occur during the recovery phase. The possibility of simultaneous ingestion of other drugs should also be considered. Dialysis has not been found to be of value for intoxication by amitriptyline alone due to low plasma concentrations of the drug.

Dosage   Back to top of page

Outpatient Adults:
The recommended initial dose for ambulatory patients is 25 mg 3 times a day. Depending upon tolerance and response, this may be increased to a total of 150 mg a day. Increases are made preferably in the late afternoon and/or bedtime doses. The sedative effect is usually rapidly apparent. The antidepressant activity may be evident within 3 or 4 days or may take up to 30 days to develop adequately.

Hospitalized Patients:
Severely ill or 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. In those patients who may not tolerate higher doses, 50 mg daily may be satisfactory. The dose may be administered in divided doses or as a single dose preferably in the evening or at bedtime.

Maintenance:
When satisfactory improvement has been reached, dosage should be reduced to the lowest amount that will maintain relief of symptoms. The usual maintenance dose is 50 to 100 mg/day in divided doses; however, in suitable patients, the total daily dosage may be given in a single dose, preferably at bedtime. It is appropriate to continue maintenance therapy throughout the active phase of the depression and for the expected duration of the depressive episode, in order to lessen the possibility of relapse.

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 non-compliance is suspected. Adjustments in dosage should be made according to the patient's clinical response and not on the basis of plasma levels.

Supplied   Back to top of page

Tablets:
10 mg:
Each blue, biconvex, discoid-shaped, film-coated tablet, engraved MSD 23 on one side, contains: Amitriptyline HCl 10 mg. Nonmedicinal ingredients: Brilliant blue (sodium and sodium alumina), calcium phosphate dibasic dihydrate, carnauba wax, colloidal silicon dioxide, cornstarch, hydroxypropyl cellulose, hydroxypropyl methylcellulose, lactose, magnesium stearate, powdered cellulose, stearic acid, talc and titanium dioxide. Bottles of 100.

25 mg:
Each yellow, biconvex, discoid-shaped, film-coated tablet, engraved MSD 45 on one side, contains: Amitriptyline HCl 25 mg. Nonmedicinal ingredients: Brilliant blue sodium alumina, calcium phosphate dibasic dihydrate, colloidal silicon dioxide, cornstarch, hydroxypropyl cellulose, hydroxypropyl methylcellulose, lactose, magnesium stearate, powdered cellulose, quinoline yellow, stearic acid, sunset yellow, talc and titanium dioxide. Bottles of 100 and 500.

50 mg:
Each beige, biconvex, discoid-shaped, film-coated tablet, engraved MSD 102 on one side, contains: Amitriptyline HCl 50 mg. Nonmedicinal ingredients: Calcium phosphate dibasic dihydrate, colloidal silicon dioxide, cornstarch, hydroxypropyl cellulose, hydroxypropyl methylcellulose, lactose, magnesium stearate, powdered cellulose, quinoline yellow, red and black iron oxides, stearic acid, sunset yellow, talc and titanium dioxide. Bottles of 100.

75 mg:
Each orange, biconvex, discoid-shaped, film-coated tablet, engraved MSD 430 on one side, contains: Amitriptyline HCl 75 mg. Nonmedicinal ingredients: Calcium phosphate dibasic dihydrate, colloidal silicon dioxide, cornstarch, hydroxypropyl cellulose, hydroxypropyl methylcellulose, lactose, magnesium stearate, powdered cellulose, stearic acid, sunset yellow alumina, talc and titanium dioxide. Bottles of 100.

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