Evaluation of isradipine and captopril alone or in combination for the treatment of hypertension.

The antihypertensive effects of isradipine and captopril were studied in 231 patients with mild-to-moderate hypertension in a double-blind, randomized, between-patient trial. Treatment was started with 1.25 mg of isradipine or 12.5 mg of captopril twice daily which, if normotension was not obtained, was increased after 4 weeks to 2.5 mg or 25 mg twice daily, respectively. If the maximum dose of each drug alone did not result in normotension, captopril (12.5 mg or, if necessary, 25 mg twice daily) was added to the isradipine regimen, and isradipine (1.25 mg or, if necessary, 2.5 mg twice daily) to the captopril regimen. Following 24 weeks of active treatment, systolic blood pressure (SBP) was significantly (p less than 0.001) reduced by isradipine (170 +/- 17 vs. 153 +/- 17 mm Hg) and by captopril (170 +/- 19 vs. 155 +/- 19 mm Hg). Diastolic blood pressure (DBP) also fell significantly (p less than 0.001) in both groups (isradipine: 106 +/- 5 vs. 93 +/- 8 mm Hg; captopril: 106 +/- 5 vs. 95 +/- 10 mm Hg). After isradipine as monotherapy, DBP was normalized in 49% of patients compared with 52% after captopril monotherapy. Combination of both drugs increased the normalization rate to 84%. The results indicate that combined treatment with a calcium antagonist and an angiotensin-converting enzyme (ACE) inhibitor is effective in lowering blood pressure, and is well tolerated as long-term therapy.