The acute hemodynamic effects of intravenous Nicardipine (N), a new calcium antagonist, were studied in 8 patients with moderate essential hypertension. The forearm arterial blood flow (ABF) was measured using plethysmography before and after N infusion: 1st step was obtained after infusion of 1 mg during 5 min then 1 mg during 25 min; a second step was obtained after the infusion of the same dose during the same time; thus a cumulative dosage of 4 mg was infused over a total duration of 60 mn. Systolic (SBP), diastolic (DBP) mean (MBP) blood pressure and heart rate (HR) were measured every minute using a non invasive device (Dinamap). Systemic vascular resistances (SVR) were calculated. Plasma concentration of N was determined at the beginning, in the middle and at the end of each step. Results are as follows: (table; see text) A 33% decrease in SVR was observed at the 2nd step whereas MBP decreased by 15% only. The date confirm the potent vasodilatory effect of intravenous N at low dosage; the BP alteration was moderate in relation to an increase in local blood flow. These results indicate that Nicardipine could be useful as part of the treatment of chronic arteriopathy and Raynaud disease.