Propionyl-L-carnitine: a new compound in the metabolic approach to the treatment of effort angina.

The effects of propionyl-L-carnitine on exercise tolerance of 12 patients with stable exertional angina were assessed in a double-blind, placebo-controlled, cross-over protocol using serial exercise tests. Compared to placebo, propionyl-L-carnitine significantly increased total work from 514 +/- 199 to 600 +/- 209 W (P less than 0.05) (17%) and prolonged exercise time and time to ischemic threshold from 515 +/- 115 to 565 +/- 109 sec (P less than 0.05) (10%) and from 375 +/- 102 to 427 +/- 93 sec (P less than 0.01) (14%), respectively. ST segment depression at the highest common work level was significantly reduced from 0.19 +/- 0.08 to 0.15 +/- 0.08 mV (P less than 0.05) (21%). No significant changes in heart rate, systolic blood pressure, and rate-pressure product at rest, at the highest common work level, on appearance of the ischemic threshold, or at peak exercise were observed after propionyl-L-carnitine treatment. No side effects were observed under propionyl-L-carnitine treatment. This study shows that propionyl-L-carnitine can significantly improve exercise tolerance in patients with stable angina. Our data seem to confirm that propionyl-L-carnitine most likely exerts its protective action via the metabolic pathway.