The pharmacology of sibutramine hydrochloride (BTS 54 524), a new antidepressant which induces rapid noradrenergic down-regulation.

1. Sibutramine hydrochloride (BTS 54 524) has been evaluated in a range of behavioural and biochemical models predictive of potential antidepressant activity. 2. BTS 54 524 exhibited potent activity in acute behavioural tests for detecting potential antidepressants. 3. BTS 54 524 rapidly and potently down-regulated rat cortical beta-adrenoceptors, being effective after only three days of oral administration. 4. BTS 54 524 showed very little activity in a range of experiments predictive of side-effect potential. 5. BTS 54 524 possesses a pharmacological profile which suggests that it may be a potent antidepressant with a rapid onset of action, and with a low potential for causing side-effects.