Endurance testing for evaluation of antianginal therapy with amlodipine, a calcium channel blocking agent

Department of Medicine, University of Colorado Health Sciences Center, Denver.

The utility of using an endurance test as well as a maximal exercise test to assess the effect of amlodipine, a dihydropyridine calcium antagonist, was evaluated in 16 patients with angina pectoris. Amlodipine, 10 mg/day, was compared with placebo in a double blind crossover study. After a 2 week single blind placebo period, patients entered a double blind crossover phase alternating between 4 weeks of placebo and 4 weeks of amlodipine. The two 4 week periods were separated by a 1 week single blind placebo washout period. The efficacy of drug therapy was assessed by frequency of angina, nitroglycerin consumption, peak oxygen consumption during a maximal treadmill exercise test and endurance time during a separate exercise test performed at 70% of the peak work capacity determined before randomization. There was a reduction in angina frequency during the double blind placebo and amlodipine studies (single blind placebo 14 +/- 2 episodes/2 weeks, double blind placebo 7 +/- 2 episodes/2 weeks [p less than 0.005], amlodipine 6 +/- 3 episodes/2 weeks, [p less than 0.005]), whereas nitroglycerin consumption was reduced with amlodipine (single blind placebo 12 +/- 4 tablets/2 weeks, double blind placebo 8 +/- 3 tablets/2 weeks, amlodipine 5 +/- 3 tablets/2 weeks [p less than 0.01]). Amlodipine produced a significant increase in peak oxygen consumption (single blind placebo 18.7 +/- 1.1 ml/kg per min, double blind placebo 18.2 +/- 1.8 ml/kg per min, amlodipine 20.4 +/- 1.6 ml/kg per min [p less than 0.05]) and endurance time (single blind placebo 15.2 +/- 1.5 min, double blind placebo 15.8 +/- 2.1 min, amlodipine 20.2 +/- 2.5 min [p less than 0.005]).(ABSTRACT TRUNCATED AT 250 WORDS)