RENAL EFFECTS OF MANIDIPINE HYDROCHLORIDE - A NEW CALCIUM-ANTAGONIST IN HYPERTENSIVE PATIENTS

The renal effects of manidipine hydrochloride were investigated in ten hospitalized patients with mild-to-moderate essential hypertension. After a one-week placebo period, manidipine was given for 1 week in a dose rising from 5 mg to 10 mg or 20 mg daily to normalise the mean blood pressure measured after 2 h. Blood pressure had decreased from 171/101 to 147/86 mm Hg at the end of manidipine treatment. The pulse rate was unaltered. Renal vascular resistance decreased from 1.90 to 1.33 dyn . s . cm-5/1.48 m2 X 10(4), and renal blood flow and glomerular filtration rate increased from 522 to 662 ml . min-1 . 1.48 m-2 and from 81 to 93 ml . min-1 . 1.48 m-2, respectively, in spite of a fall in renal perfusion pressure. Manidipine reduced the filtration fraction from 0.260 to 0.243, suggesting a preferential reduction in efferent arteriolar resistance. The fractional excretion of sodium and potassium did not change. Manidipine did not produce any significant alteration in plasma renin activity or in the plasma aldosterone concentration. The results indicate that manidipine has favourable renal effects and a concomitant hypotensive action in patients with mild-to-moderate essential hypertension.