Isradipine in the treatment of angina pectoris

Abstract Isradipine (PN 200-110) is a second-generation dihydropyridine derivative calcium antagonist. This study compares isradipine with nifedipine in 29 patients with chronic stable angina in a randomized double-blind cross-over trial with sequential treadmill exercise evaluations (modified Bruce) and anginal diaries. The study plan included a two-week, single-blind placebo washout period and four weeks of titration and treatment with each drug interrupted by one week of placebo treatment. Dosing goals were 7.5 mg three times per day for isradipine and 30 mg three times per day for nifedipine. Both treatments reduced systolic and diastolic blood pressure and increased heart rate while resting to a similar degree. Average study endpoints were, for baseline, isradipine, and nifedipine, respectively: total exercise time in seconds, 447, 581, and 578; time to onset angina in seconds, 344, 512, and 498; number of anginal episodes per two weeks, 20, 12, and 9; and number of nitroglycerin tablets taken in two weeks, 11, 8, and 6. No difference between the treatments was statistically significant. There were significant differences in adverse reactions with cardiovascular discomfort for those patients receiving nifedipine outnumbering discomfort for those patients receiving isradipine 22 to 9; neurologic discomfort 38 to 16; and gastrointestinal discomfort 13 to 10. Two patients discontinued nifedipine treatment for adverse reactions, and none withdrew from isradipine treatment. Thus, isradipine proved to be equal to nifedipine in improving exercise performance and reducing the incidence of angina in patients with chronic stable angina. At the same time, isradipine was better tolerated.