[Acute hypotensive effect of a central dopaminergic agonist, piribedil, administered intravenously in the normotensive human].

Ten normotensive patients including 5 parkinsonian and 5 dystonic patients received 3 mg piribedil intravenously over a 15 min period. This dopamine receptor agonist rapidly induced a fall in blood pressure together with a simultaneous reduction in heart rate and temperature. No change was observed when patients (four) were pretreated with a dopamine receptor blocking agent, haloperidol. It is concluded that acute dopamine receptor stimulation leads to a decrease in blood pressure. The hypotension could be centrally-mediated since the hypothermia, considered to be central in origin, parallels the blood pressure and heart rate changes.