Clinical pharmacology of sibutramine hydrochloride (BTS 54524), a new antidepressant, in healthy volunteers.

The cardiovascular, anticholinergic and central effects of single doses of 30, 45 and 60 mg of sibutramine hydrochloride (BTS 54524), a new potential antidepressant, were compared with amitriptyline (50 mg) and placebo given at weekly intervals in a randomised design to six healthy male volunteers. Sibutramine was associated with increases in both supine heart rate and systolic blood pressure at 1, 2 and 6 h after 60 mg (P less than 0.05). Amitriptyline caused a significant 50-60% decrease in salivation compared with placebo at 2 and 6 h but there were no changes with sibutramine. No significant changes in pupil size were detected with either drug. Visual analogue rating scales (VARS) revealed significant drowsiness with amitriptyline but neither sedative nor stimulant effects with sibutramine. Impairments of simple auditory and visual reaction times, visual two-choice reaction time, finger tapping and trail making, measured using an automated test battery, occurred with amitriptyline compared with sibutramine. If sibutramine proves to be an effective antidepressant it should be devoid of anticholinergic or central depressant effects. Chronic dosage studies are indicated to evaluate the clinical significance of its cardiovascular effects.