[Effects of manidipine hydrochloride on renal function in renal parenchymal hypertensive patients]

The incidence of renal parenchymal hypertension is highest in patients with secondary hypertension. It is important to prevent the progression of renal dysfunction by appropriate treatment, especially by means of antihypertensive drugs. Calcium channel blockers are considered to have the advantage as antihypertensive drugs of maintaining the renal blood flow, even though the perfusion pressure may be decreased. However, these drugs can involve the risk of deteriorating the glomerular function due to hyperfiltration. To investigate whether calcium channel blockers can prevent the deterioration of renal function in renal parenchymal hypertensive patients, we administered manidipine hydrochloride (20 mg, once a day, 24 weeks) to 16 outpatients and evaluated its effects on blood pressure and renal function. The following results were obtained. (1) The systolic and diastolic pressure decreased from 2 and 4 weeks after administration, respectively. A stable antihypertensive effect appeared thereafter and no change was observed in the pulse rate. (2) The renal vascular resistance tended to decrease slightly. The glomerular filtration rate and renal blood flow did not change in spite of the decreased perfusion pressure. (3) No changes were seen in urinary protein, endocrine factors and cardiac function. (4) In some of the cases with decreased GFR (< 70ml/min), the drug could not prevent deterioration of the renal function and did not produce an antihypertensive effect.