Experience of long term treatment and different dosage regimens of isosorbide 5-mononitrate

The results of 2 clinical studies of controlled-release isosorbide 5-mononitrate (Imdur) in patients with angina pectoris are presented. In an open study in 106 patients the antianginal efficacy of controlled-release isosorbide 5-mononitrate 60 mg once daily was demonstrated by a progressive reduction in the use of short-acting glyceryl trinitrate and in the number of anginal attacks over 6 months. The only significant side effect was headache, which generally disappeared rapidly (after an average of 5 to 6 days). 30 patients were treated in a 1-week single-blind crossover study comparing controlled-release isosorbide 60 mg once daily with a conventional formulation of the drug 20 mg 3 times daily. Both regimens produced similar antianginal and anti-ischaemic effects when the patients were tested by standard ergometry, and the only significant side effect (transient headache) was equally frequent with both regimens.