Calcium antagonists in geriatric patients: diltiazem in elderly persons with hypertension.

Pharmacodynamics and disposition of diltiazem were determined in twelve young (30 to 39 years of age) and twelve elderly (65 to 83 years of age) persons with hypertension after they had received diltiazem by rapid intravenous and long-term oral administration. Plasma disappearance half-life of diltiazem increased similarly and significantly in both groups with long-term dosing (young: rapid intravenous, 3.7 +/- 0.8 hour; long-term oral, 6.3 +/- 1 hour [mean +/- SE]; elderly: rapid intravenous, 3.8 +/- 0.7 hour; long-term oral, 7.2 +/- 2.1 hour; p less than 0.01). During long-term therapy both systolic and diastolic blood pressure was significantly lowered from baseline beyond a 12-hour dose interval, with greater decreases in systolic blood pressure in the elderly. Heart rate was decreased with long-term therapy in both groups. Maximal prolongation of PR interval was greater in the young after the intravenous dose (young: 46 +/- 28 msec; elderly: 24 +/- 11 msec; p less than .01), but this effect was not seen with long-term therapy. These data demonstrate that diltiazem administered every 12 hours is an effective antihypertensive agent in both young and elderly patients.