Effects of Calcium Antagonists on Hemodynamics in Elderly Hypertensives

Abstract

The effects of calcium antagonists (nifedipine, diltiazem and verapamil) on hemodynamics were investigated in elderly 36 hypertensives (systolic blood pressure exceeded 160mmHg) and 24 normotensives (systolic blood pressure below 159mmHg), aged 70 to 85 years. Nifedipine (10mg, sublingual) decreased blood pressure from 178±19/70±11 to 140±11/55±8 mmHg (mean±SD) in hypertensives and from 127±13/58±6 to 108±12/49±5mmHg in normotensives (preadministration to 30min after administration). The drug increased heart rate and cardiac output, and decreased total peripheral resistance in both hypertensives and normotensives. Diltiazem (0.1mg/min×30min, then 0.2mg/min, i.v. infusion) decreased blood pressure from 180±17/72±12 to 159±15/62±11 mmHg in hypertensives and from 130±14/51±7 to 126±15/48±9mmHg in normotensives. The drug reduced heart rate and total peripheral resistance, and increased cardiac output in hypertensives. Verapamil (0.1mg/min×30min, then 0.2mg/min×30min, i.v. infusion) decreased blood pressure from 180±12/74±12 to 149±20/62±9mmHg in hypertensives and from 126±11/57±5 to 111±9/49±5mmHg in normotensives. The drug reduced heart rate and total peripheral resistance, and increased cardiac output in hypertensives. Hemodynamic changes induced by calcium antagonists were greater in hypertensives than in normotesives. Nifedipine did not change P-R interval in electrocardiogram. Diltiazem and verapamil significantly prolonged P-R interval, but not produce second or third degree atrioventricular block. The fall in systolic blood pressure induced by nifedipine, diltiazem and verapamil was correlated with preadministration systolic blood pressure and also with total peripheral resistance, but not with cardiac output. Low dose calcium antagonists, compared with effective dose in middle hypertensives, were effective to reduce blood pressure in eiderly hypertensives. The favorable hemodynamic effects of calcium antagonists, which decreased blood pressure and total peripheral resistance and increased cardiac output, suggest that calcium antagonists may be efficacious in the treatment of elderly hypertension.