NORTRIPTYLINE HYDROCHLORIDE CAPSULES USP
Nortriptyline hydrochloride is 1-Propanamine, 3-(10,11-dihydro-5 H -dibenzo[ a,d ]cyclohepten-5-ylidene)- N -methyl-, hydrochloride.
The structural formula is as follows:
C19H21N•HCl M.W. 299.8
Nortriptyline hydrochloride is a white to off-white powder, having a slight, characteristic odor. It is soluble in water and in chloroform; sparingly soluble in methanol; and practically insoluble in most organic solvents.
Each capsule, for oral administration, contains nortriptyline hydrochloride equivalent to 10 mg, 25 mg, 50 mg or 75 mg nortriptyline.
In addition, each capsule contains the following inactive ingredients: colloidal silicon dioxide, corn starch, gelatin, glacial acetic acid, glycerin, methylparaben, propylparaben, silicone fluid, sodium lauryl sulfate, and titanium dioxide. The 10 mg, 25 mg and 75 mg capsules also contain D&C Yellow #10, FD&C Yellow #6, and FD&C Blue #1.
The mechanism of mood elevation by tricyclic antidepressants is at present unknown. Nortriptyline hydrochloride is not a monoamine oxidase inhibitor. It inhibits the activity of such diverse agents as histamine, 5‑hydroxytryptamine, and acetylcholine. It increases the pressor effect of norepinephrine but blocks the pressor response of phenethylamine. Studies suggest that nortriptyline hydrochloride interferes with the transport, release, and storage of catecholamines. Operant conditioning techniques in rats and pigeons suggest that nortriptyline hydrochloride has a combination of stimulant and depressant properties.