The cardiovascular effects and the pharmacokinetics of a new selective alpha-2 adrenoceptor antagonist, benalfocin, and its active metabolite, both compounds with a similar receptor affinity profile, were examined in healthy volunteers during repeated dosage. Significant diastolic blood pressure lowering effects were observed on the first and the last day of the treatment persisting throughout the dosage interval. Furthermore, heart rate reductions were found on these days which were significantly correlated with both the parent compound's and the metabolite's plasma concentrations and their sum. Pharmacokinetics remained unchanged after a 1-wk oral dosing as compared to a single oral dose; the plasma half-life of the metabolite was 3-fold longer than that of the parent compound. In normotensive subjects, benalfocin produced blood pressure and heart rate reducing effects, the latter being more correlated with the metabolite's plasma concentrations. Furthermore, results suggest that the compound's known cholinergic effects may be particularly related to the metabolite and that this molecule is an interesting cardiovascular compound.