Effects of the calcium antagonist isradipine on 24-hour ambulatory blood pressure, platelet aggregation, and neutrophil oxygen free radicals in hypertension.

The effects of isradipine on ambulatory blood pressure, platelet aggregation, and oxygen free radicals were assessed in 30 patients with hypertension in a non-comparative 16-week study. After 4 weeks of placebo run-in, patients received isradipine at 2.5 mg twice daily for 12 weeks. The average supine systolic/diastolic blood pressure (155 +/- 17/101 +/- 11 mm Hg) was significantly reduced at the end of treatment (144 +/- 13/95 +/- 9 mm Hg; p less than 0.01). The heart rate was not significantly altered. Isradipine had no adverse effects on red or white blood cells or on plasma viscosity. The thromboxane B2 level and epinephrine-induced platelet aggregation were significantly (p less than 0.05) reduced. High-density lipoprotein cholesterol was significantly (p less than 0.01) increased after vs. before treatment; total cholesterol was significantly (p less than 0.05) increased at midstudy, but this was not significant at the end of the study. Other biochemical parameters were unchanged. Studies of neutrophil oxygen free radicals by serum opsonized zymosan and phorbol myristate acetate were not affected by isradipine. In conclusion, isradipine is an effective antihypertensive agent that also has beneficial effects on platelet aggregation and lipids while having no effects on neutrophil oxygen free radicals or most of the biochemical variables tested, making it an ideal agent for hypertension.