In 24 men with angina after exertion the authors assessed, using ergometry, the action of molsidomine retard and isosorbide dinitrate retard after a single dose and after tree-week administration of the drug. The authors found that 8 mg of molsidomine retard in a single dose had a somewhat more potent effect than 40 mg isosorbide dinitrate retard. After prolonged administration the effect of both drugs on haemodynamics diminished and in molsidomine a significant decline of action was observed before development of a reduced S-T segment on the ECG. After three weeks' administration the effects of both drugs were comparable. After neither drug clinically significant tolerance developed when the drug was administered every 8 hours. In the conclusion the authors discuss possible mechanisms involved in development of tolerance.

Keywords: Adult; Angina Pectoris /drug therapy/; Delayed-Action Preparations; Electrocardiography /drug effects/; Exercise Test; Heart Rate /drug effects/; Humans; Isosorbide Dinitrate /administration & dosage/; Male; Middle Aged; Molsidomine /administration & dosage/