title: The effect of minoxidil on blood pressure and plasma renin activity in patients with essential and renal hypertension.
abstract: The effect of the new vasodilator, minoxidil, on blood pressure and plasma renin activity was studied in 21 hypertensive patients: 12 patients with essential and 9 with renal hypertension. The average maximum dosage of minoxidil was 27.9 +/- 6.0 mg/day (M +/- SD). Average duration of treatment was 84.5 days. During the observation period the average systolic blood pressure fell from 195 +/- 18 to 159 +/- 7 mm Hg (M +/- SD), and the mean diastolic blood pressure fell from 120 +/- 8.3 to 92.5 +/- 8 mm Hg (p less than 0.01). These patients had been treated earlier with other antihypertensive agents, such as reserpine, saluretics, hydralazine, alpha-methyldopa, and clonidine, without any significant reduction in blood pressure. Before treatment, plasma renin activity after resting was 59 +/- 6.4 ng/ml/16 h (M +/- SE) and after saluretics and orthostasis 89 +/- 12.7 ng/ml/16 h. After treatment, the decline in renin value after resting was statistically significant: 42.7 +/- 3.3 ng/ml/16 h (p less than 0.05), and the stimulated renin had fallen to 70 +/- 3.4 ng/ml/16 h (p greater than 0.1). A comparison of the renin stimulation values of patients with renal hypertension also revealed a significant reduction (p less than 0.01). Side effects which appeared at a daily dose of 15 to 30 mg consisted mainly of tachycardia and fluid retention and could be controlled by the administration of propranolol and chlorthalidone. In 5 women and in 1 man was observed a cosmetically disturbing, reversible hypertrichosis. Orthostatic hypotension was observed in one patient. Minoxidil is an effective antihypertensive agent. However, because of its side effects, it generally must be administered with beta-receptor blocking agents and saluretics. It is possible that its blood pressure lowering effect is due, at least in part, to a suppression of the plasma renin activity.
mesh_terms: D000328:Adult; D000368:Aged; D001794:Blood Pressure / Q000187:drug effects*; D002986:Clinical Trials as Topic; D004487:Edema / Q000139:chemically induced; D005260:Female; D006801:Humans; D006973:Hypertension / Q000097:blood / Q000188:drug therapy* / Q000503:physiopathology; D006977:Hypertension, Renal / Q000188:drug therapy*; D006983:Hypertrichosis / Q000139:chemically induced; D008297:Male; D008875:Middle Aged; D008914:Minoxidil / Q000009:adverse effects / Q000627:therapeutic use*; D011743:Pyrimidines / Q000627:therapeutic use*; D012083:Renin / Q000097:blood*; D013610:Tachycardia / Q000139:chemically induced
chemical_list: D011743:Pyrimidines; D008914:Minoxidil; D012083:Renin