Imipramine pharmacokinetics in depressed geriatric patients.

Pharmacokinetics of single dose (25 mg i.m.) of imipramine was studied in geriatric and young adult patients with mood disorders requiring antidepressant treatment. Imipramine and its principal metabolites were determined by means of a high performance liquid chromatography method with electrochemical detection. Serum concentrations analysis was performed according to a bicompartmental open model. A relationship between age and kinetic parameters such as area under the curve, elimination phase constant, half-life and total body clearance was observed. Significant differences were demonstrated between elderly and young adult patients when comparing these parameters. It is concluded that geriatric patients treated with imipramine should receive doses of about 60% of those of young adults.