The effects of a single dose of
alinidine (0.5 mg/kg i.v.), the N-allyl-derivative of
clonidine, on heart rate and blood pressure were investigated in healthy volunteers and in patients with
hyperkinetic heart syndrome, at rest and during bicycle exercise. In healthy volunteers plasma
catecholamine levels were also determined.
Alinidine did not change heart rate at rest in the healthy volunteers but it did significantly reduce exercise-induced
tachycardia, whereas blood pressure and plasma
catecholamine levels were not significantly affected by
alinidine, either at rest or during exercise. In patients with
hyperkinetic heart syndrome,
alinidine reduced heart rate at rest and during exercise to a similar extent as
propranolol (0.1 mg/kg i.v.). The blood pressure did not change with
alinidine but it was significantly reduced by
propranolol. The observation that an
alinidine-induced reduction of heart rate occurs without a concomitant fall in blood pressure, and without a
clonidine-like symphatho-inhibitory action, is in line with experimental findings suggesting a specific bradycardic action of
alinidine under short-term conditions.