Effect of cianopramine, a tricyclic antidepressant, on platelet serotonin uptake and peripheral adrenergic function

Cianopramine, a new tricyclic antidepressant, is a potent inhibitor of neuronal serotonin (5-HT) uptake in animals. We studied the effect of cianopramine on 5-HT uptake (ex vivo) in platelets and on peripheral neuronal adrenergic function in catecholamine pressure response tests in normal subjects. The inhibition of 14C-labeled 5-HT uptake into platelets was 57% +/- 12% 2 hr after 0.5 mg (after 24 hr: 27% +/- 13%), 59% +/- 10% 2 hr after 1 mg (24 hr: 41% +/- 13%), and 80% +/- 2% 2 hr after 2 mg cianopramine (24 hr: 52% +/- 10%). Systolic blood pressure response to intravenous tyramine and norepinephrine was unchanged after 2 mg cianopramine. The phenylephrine dose required for an increase of 40 mm Hg in systolic blood pressure was 67 +/- 25 micrograms/min before cianopramine and 86 +/- 32 micrograms/min 2 hr after 2 mg cianopramine, which suggests weak alpha-receptor antagonism of cianopramine. Our results in man are consistent with potent, specific 5-HT uptake inhibition by cianopramine without a clinically relevant effect on peripheral neuronal norepinephrine reuptake.