The effects of age on the pharmacodynamics and pharmacokinetics of two formulations of verapamil.

The present study, undertaken in general practice, was designed to evaluate the effects of age on the pharmacodynamics and pharmacokinetics of a conventional and a slow-release formulation (Securon SR) of verapamil. Two groups of 12 patients with essential hypertension were treated in an open, randomized, crossover study. One group was younger than 65 years, mean 58 (range 50-64 years) and the other was 65 years and older, mean 72 (range 66-77 years). The patients were titrated through three steps with the two different formulations to efficacy or to maximal dosage. During a 4-week drug-free run-in period the mean blood pressures were 167 +/- 14/103 +/- 4, 168 +/- 18/105 +/- 6, and 168 +/- 18/105 +/- 5 mm Hg at 0, 2, and 4 weeks, respectively, for the whole group. The final blood pressure at control showed a fall with sustained-release verapamil for systolic blood pressure (SBP) and diastolic blood pressure (DBP) of 15 +/- 16 and 17 +/- 5 mm Hg for the younger group and 14 +/- 16 and 14 +/- 6 mm Hg for the older group. For the conventional formulation the falls of SBP and DBP were 14 +/- 18 and 18 +/- 8 mm Hg for the younger group and 19 +/- 16 and 13 +/- 9 mm Hg for the older group. There were no significant differences between the responses to the two formulations nor between the two age groups. The pharmacokinetics of both formulations were investigated at steady state and no significant effects of age were observed. However, there were significant differences between the time-concentration profiles for the formulations. These findings suggest that there are no significant effects of age on the pharmacodynamics and pharmacokinetics of verapamil.