Renal and antihypertensive effects of felodipine in hypertensive patients.

The effects of small doses of felodipine (10 mg twice daily) on blood pressure, renal function and sodium and water balance were studied in 11 patients with arterial hypertension. Felodipine significantly reduced systolic and diastolic blood pressure: most of the antihypertensive effect was already evident on day 1 of administration (-18/-11 mmHg) and only slightly increased during the subsequent week. Heart rate rose moderately only during day 1 of felodipine administration (+7 beats/min). Sodium excretion was increased during days 1 and 2, and no signs of water and electrolyte retention was observed in the week during which the balance study could be performed (Na, -135 +/- 65 mmol/7 days). At relatively low doses felodipine appears to be an effective antihypertensive agent, initially exerting some diuretic and natriuretic action and subsequently being devoid of a water- and sodium-retaining action.