Trials with an adenosine analogue as antianginal medication

The potential antianginal effects of orally administered ethyl-adenosine-5-carboxylate hydrochloride (EACH) were assessed in 9 patients with stable angina pectoris who underwent two standardized exercise tests for 3 consecutive days. The first daily exercise performed after placebo revealed no daily variation. The second test was preceded by placebo, 26 mg EACH or 33 mg EACH administered in a double-blind fashion with the use of crossover design. After the completion of the study in the first 6 patients, the 33-mg dose of EACH had to be discontinued because 3 patients had severe angina and another one had nausea and diffuse numbness after this dose. In the remaining 3 patients a 6-mg dose of EACH was used instead of 33 mg, after which the study was terminated because no difference could be determined. EACH, 26-mg and 6-mg, had no significant effect on resting and exercise heart rate, on blood pressure, on onset or duration of angina and positive-exercise electrocardiogram, or on exercise duration. Our study revealed that EACH had no potential antianginal effect and that at a dosage of 33 mg it may induce angina.