Safety of the coadministration of carvedilol and nifedipine sustained-release in the treatment of essential hypertension.

A single-center, randomized, double-blind study in 14 hypertensive patients was conducted to investigate the acute and short-term safety of the addition of carvedilol to pre-existent nifedipine sustained-release (SR) therapy as well as on the addition of nifedipine SR to pre-existent carvedilol therapy when treatment with the initial monotherapy did not adequately control blood pressure. Mean supine blood pressure at study entry was 171/106 mm Hg. Acute reductions in blood pressure were greater with combination treatment than with either monotherapy. Dosing with 25 mg carvedilol once daily or 20 mg nifedipine SR twice daily resulted in mean peak reductions in supine blood pressure of 21/11 and 20/16 mm Hg, respectively, after 1 week of treatment with each respective monotherapy. With combination treatment, mean peak reductions (after dosing on days 1, 3, and 10) ranged from 26 to 40 mm Hg in supine systolic blood pressure and from 14 to 23 mm Hg in supine diastolic blood pressure. Acute changes in mean standing systolic and diastolic pressures were comparable to those in the supine position. Combination treatment resulted in an additive acute antihypertensive response without synergistic potentiation. Neither monotherapy nor the coadministration of the two agents in the doses used resulted in a significant antihypertensive response at the time of trough plasma levels of study medication, perhaps due to the short-term nature of the trial which did not allow the full antihypertensive effect of either agent to be realized. Before dosing with study medication, heart rates were minimally changed from study entry levels with either monotherapy or combination treatment.(ABSTRACT TRUNCATED AT 250 WORDS)