[Pharmacokinetics and pharmacodynamics of antihypertensive drugs in the elderly]

In order to study pharmacokinetics and pharmacodynamics of antihypertensive drugs in the elderly, plasma concentration and blood pressure response to 4 antihypertensive drugs with different modes of action (captopril, nifedipine retard tablet, bunazosin, arotinolol) were measured in young and elderly hypertensive patients without liver or renal dysfunction after oral administration of each drug. Systolic and diastolic blood pressure fell after 25 mg of captopril in both groups and the rate of decrease in each group was similar. Plasma concentration of captopril at 1 and 2 hours after administration in the elderly group tended to be higher than in the young group. Suppression of angiotensin-converting enzyme activity persisted longer in the elderly group than in the young group. The area under the curve (AUC) of captopril in the elderly group (335.4 +/- 98.6 hr.2ng/ml) was significantly greater than in the young group (186.7 +/- 79.9) (p less than 0.005), while no significant differences in Cmax, Tmax and T1/2 were observed. The percent decrease in systolic blood pressure in the elderly group (25.2 +/- 10.2%) after 1 hour of nifedipine tablet (20 mg) was significantly higher than in the young group (16.6 +/- 1.5%) (p less than 0.05). Cmax and AUC of nifedipine in the elderly tended to be higher than in the young group (303.5 v.s. 210.0 ng/ml and 1258.9 v.s. 725.1 hr.ng/ml, p less than 0.1, respectively). The percent decrease of diastolic blood pressure after 2 mg of bunazosin was also significantly higher in the elderly group than in the young group (p less than 0.05).2+ antihypertensive response after captopril and arotinolol in two groups.