Felodipine in chronic stable angina: a randomized, double-blind, placebo-controlled, crossover study

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Abstract
To investigate the antianginal efficacy and tolerability of felodipine, a new dihydropyridine calcium antagonist, 20patients with stable exertional angina, not completely controlled by beta-blocker monotherapy, entered a randomized, double-blind, placebo-controlled, crossover study. Patients on standard beta-blocker therapy, who had at least 3 weekly anginal episodes and a reproducible exercise test (stopped for angina and ECG signs of ischaemia) at the end of 2 weeks placebo treatment, were eligible for the study. They were randomized to one sequence of treatment: felodipine 5 mg twice daily for 2 weeks followed by placebo for a further 2 weeks, or vice versa. Beta-blocker treatment was unchanged throughout the study. A treadmill test was carried out at the end of each crossover period, 2.4 h after drug administration. The number of anginal attacks and nitroglycerin consumption was recorded on a diary card. At rest, felodipine significantly (P < 0.05) reduced standing systolic but not diastolic blood pressure. Heart rate was not modified by the active treatment. At ischaemic threshold and at peak exercise, heart rate, systolic blood pressure and rate-pressure product remained unchanged. Exercise duration was increased by felodipine (P<0.01) and maximal ST change was reduced (P <0.01). Time to 1 mm ST depression was prolonged non-significantly by felodipine (basal 5.7 ± 15, felodipine 7.4 ± 2.0, placebo 6.6 ±1.5 min). The number of patients who stopped exercise due to angina and ST change was 20/20 at baseline, 16/20 with placebo and 10/20 with felodipine. Felodipine significantly reduced weekly anginal episodes (P <0.01). The drug was well tolerated: however, three patients experienced ankle oedema, and one asymptomatic hypotension. These results suggest that chronic administration of felodipine, 5 mg twice daily, reduces anginal episodes and increases exercise tolerance in patients with exercise angina not controlled by beta-blocker monotherapy.