Pharmacokinetics of carvedilol in older and younger patients.

Carvedilol, a combined beta- and alpha 1-blocking drug, was given to 8 young (age 39-47) and 21 old (age 64-79) patients with essential hypertension. Clinical and pharmacokinetic responses to 12.5, 25 and 50 mg were determined and compared. In both age groups, pharmacokinetic data were similar with all three doses of carvedilol. Peak blood levels were reached within 90 minutes and at 24 hours the trough blood level was less than 10% of the peak level. Carvedilol or its metabolite did not accumulate. Falls in systolic and diastolic BP were greater than 7 mmHg in 28 of the 29 patients. The falls in diastolic BP did not differ between groups but the older group had a greater fall in systolic BP. However, the systolic BP of the older group was higher and expressed as a percentage, the falls in BP did not differ. The time to peak fall in BP was about 4 hours and was always after the time to peak blood level. There was no correlation between blood level and BP fall. When the drug was administered 24 h after the previous dose, a further fall in BP was seen indicating a greater effect at peak drug levels. Side effects were few and, during the chronic study, there was no postural hypotension or postural hypotensive symptoms. On the study days, five patients developed postural hypotension with symptoms. These were not observed at other times and may have been due to decreased sympathetic outflow on the study days. Carvedilol lowered BP in order and younger patients. There were no significant effects of age on its pharmacokinetics. Carvedilol is an effective antihypertensive agent that can be used in people with essential hypertension in all age groups.