Improved exercise tolerance after propranolol, diltiazem or nifedipine in angina pectoris: comparison at 1, 3 and 8 hours and correlation with plasma drug concentration.

ABSTRACT

Exercise tolerance 1, 3 and 8 hours after 80 mg of propranolol, 120 mg of diltiazem and 20 mg of nifedipine, and after 20 minutes of 0.6 mg of sublingual nitroglycerin were compared with placebo in 15 men who had chronic stable angina pectoris. Three hours after drug ingestion, the exercise time was prolonged by 72 +/- 26, 162 +/- 27 and 161 +/- 30 seconds (p less than 0.05) for propranolol, diltiazem and nifedipine, respectively, and by 123 +/- 35 seconds (p less than 0.001) 20 minutes after sublingual nitroglycerin compared with placebo. The onset of ST-segment depression greater than or equal to 0.1 mV was delayed by 120 +/- 34, 203 +/- 29 and 189 +/- 35 seconds (p less than 0.05) and by 79 +/- 23 seconds (p less than 0.05), respectively. After propranolol, the peak rate-pressure product decreased compared with placebo (15.1 +/- 1.1 U [10(-3)] vs 20.0 +/- 1.5 U, p less than 0.01). In contrast, the peak rate-pressure product was greater after diltiazem and nifedipine than after placebo (22.2 +/- 1.3 U [p less than 0.05] and 23.8 +/- 1.4 U [p less than 0.01]). The maximal increase in exercise tolerance was most marked for each drug at 3 hours, but was also significant at 1 hour for nifedipine and at 8 hours for diltiazem. At 3 hours, an increase in exercise time of more than 2 minutes was observed in 4 of 6 patients who had plasma propranolol concentrations greater than 40 ng/ml, 8 of 9 who had a plasma diltiazem concentration greater than 150 ng/ml, and in 7 of 7 who had a plasma nifedipine concentration greater than 90 ng/ml.(ABSTRACT TRUNCATED AT 250 WORDS)