Improved blood pressure control with isradipine in hypertensive patients treated with pindolol.

Isradipine is a new calcium antagonist of the dihydropyridine type with marked vasodilator activity and minimal negative inotropic effects. It is a potent antihypertensive drug when given as monotherapy. This was a randomized double-blind crossover study of 16 weeks' duration, including 80 hypertensive patients with diastolic blood pressures of at least 95 mm Hg who had shown clinically relevant antihypertensive responses, but no normalization of blood pressure during pindolol 10 to 15 mg once daily as monotherapy. Either isradipine or placebo was added to the beta-blocker at doses of either 2.5 mg or 5 mg twice daily, which was doubled after four weeks if the diastolic blood pressure remained more than 90 mm Hg. The addition of isradipine (in either dose regimen) caused a pronounced reduction of blood pressure with no changes in heart rate. Five patients were withdrawn from the study because of adverse events while receiving isradipine compared with three taking placebo. A further three patients withdrew from the study because of adverse events (one patient) or lack of efficacy (two patients) during placebo treatment. These results indicate that isradipine is an effective and well-tolerated adjunct to beta-blockers in hypertensive patients.