Tricyclic antidepressants (TCAs)

Tricyclic antidepressants (TCAs)

a. Amitriptyline (Synonym: Envil, Amitril, Tryptomer, Amitone, Trilin)

Synthesis

Properties and uses: It is a white or almost white powder or colourless crystals. Soluble in water, in alcohol, and in methylene chloride. It is one of the most anticholinergic and sedative of the TCAs, because it lacks the ring electronenriching nitrogen atom of imipramine. Used for the treatment of depression associated with anxiety. It is also useful in the management of enuresis in children and adolescents.

Assay: Dissolve the sample in alcohol. Titrate with 0.1 M sodium hydroxide and determine the end point potentiometrically.

Storage: It should be stored in well-closed airtight containers and protected from light.

Dose: Usual dose is 50–75 mg daily on divided doses or at single dose at night.

Dosage forms: Amitriptyline HCl tablets I.P., Amitriptyline tablets B.P.

b. Nortriptyline (Synonym: Damelor, Aventyl HCl, Nordep, Nortin, Depival)

Synthesis

Route I. From: Phthalic anhydride

Nortriptyline

Route II. From 10, 11-dihydro cyclohepten-5-one

Properties and uses: It is a white or almost white powder, soluble in ethanol and in methylene chloride, but sparingly soluble in water. A tricyclic, with moderate sedative and moderate antimuscarnic effects. It posseses antidepressant and tranquillizing properties, similar to those of the parent drug amitriptyline. It produces less anticholinergic, less sedative, and more stimulant action than amitriptyline.

Assay: Dissolve the sample in ethanol, add 0.1 M hydrochloric acid and perform potentiometric titration using 0.1 M sodium hydroxide.

Storage: It should be stored in well-closed airtight containers and protected from light.

Dose: For depression: Adult: 75–100 mg daily in 3–4 divided doses, increase gradually up to 150 mg daily in severe depression. Child: Adolescent: 30–50 mg daily in divided doses. Elderly: 30–50 mg daily in divided doses.

Dosage forms: Nortriptyline HCl tablets I.P., Nortriptyline capsules B.P., Nortriptyline tablets B.P.