Amitriptyline Hydrochloride - Pharmacology TABLET, FILM COATED

Antidepressants increased the risk compared to placebo of suicidal thinking and behavior (suicidality) in children, adolescents, and young adults in short-term studies of major depressive disorder (MDD) and other psychiatric disorders. Anyone considering the use of amitriptyline hydrochloride tablets or any other antidepressant in a child, adolescent, or young adult must balance this risk with the clinical need. 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 in risk with antidepressants compared to placebo in adults aged 65 and older. Depression and certain other psychiatric disorders are themselves associated with increases in the risk of suicide. Patients of all ages who are started on antidepressant therapy should be monitored appropriately and observed closely for clinical worsening, suicidality, or unusual changes in behavior. Families and caregivers should be advised of the need for close observation and communication with the prescriber. Amitriptyline hydrochloride tablets are not approved for use in pediatric patients (see Warnings: Clinical Worsening and Suicide Risk, Precautions: Information for Patients, and Precautions: Pediatric Use.)

Amitriptyline HCl is 3-(10,11-dihydro-5H-dibenzo [a, d] cycloheptene-5-ylidene)-N,N-dimethyl-1-propanamine hydrochloride. Its empirical formula is C ₂₀H ₂₃NHCl, and its structural formula is:

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.

Amitriptyline HCl is supplied as 10 mg, 25 mg, 50 mg, 75 mg, 100 mg or 150 mg tablets. Each tablet contains the following inactive ingredients: colloidal silicon dioxide, hypromellose, lactose monohydrate, magnesium stearate, microcrystalline cellulose, polyethylene glycol, polysorbate, sodium starch glycolate and titanium dioxide. The 10 mg tablets also contain FD&C blue #1 lake. The 25 mg tablets also contain D&C yellow #10 lake and FD&C blue #2 lake. The 50 mg tablets also contain synthetic black iron oxide, synthetic red iron oxide and synthetic yellow iron oxide. The 75 mg tablets also contain FD&C yellow #6 lake. The 100 mg tablets also contain D&C red #33 lake and FD&C red #40 lake. The 150 mg tablets also contain FD&C blue #2 lake and FD&C yellow #6 lake.

Amitriptyline hydrochloride 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.

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*Based on a maximum recommended amitriptyline dose of 150 mg/day or 3 mg/kg/day for a 50 kg patient.

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