DESCRIPTION
Amitriptyline HCl is 3-(10,11-dihydro-5 H -dibenzo [a, d ] cycloheptene-5-ylidene)- N,N -dimethyl-1-propanamine hydrochloride. Its empirical formula is C20H23N·HCl.
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.
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
ACTIONS
ELAVIL 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.
|
CLINICAL PHARMACOLOGY
ELAVIL (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 14 C-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.
|
