Treatment of coronary heart disease with isosorbide mononitrate ('Elantan' 20): a multi-centre study in hospital and general practice.

An open, multi-centre clinical trial was carried out in 537 hospital patients and 2138 general practice patients to evaluate the efficacy and tolerance of isosorbide 5-mononitrate in the treatment of angina pectoris. Prior to entry into the trial, angina attack frequency and acute glyceryl trinitrate consumption were assessed during previous, in most cases unsatisfactory, anti-anginal therapy. After a treatment-free washout period of 3 days, graded multi-stage exercise testing was performed and then treatment started with 20 mg isosorbide mononitrate 3-times per day. Exercise testing was repeated after 14 days' therapy and, in the case of the hospital patients, also 4 to 5 hours after the first dose of isosorbide mononitrate. At the end of the 14-day treatment period, angina attack frequency and glyceryl trinitrate consumption were again assessed. Similar results were obtained for both hospital and general practice patients. Changing to isosorbide mononitrate resulted in a marked reduction in angina frequency, with complete elimination of angina attacks in approximately half of the patients; nocturnal angina, present in approximately 20% of the patients during previous therapy, virtually disappeared during isosorbide mononitrate therapy. Exercise tolerance and performance improved in the majority of patients, with a marked increase in the number of patients able to exercise to the level at which some symptom other than angina pectoris caused them to stop. ST-depression during exercise and exercise-induced arrhythmias also showed clear reductions during isosorbide mononitrate therapy. Tolerance to isosorbide mononitrate was good, the expected 'nitrate headaches' being the only common side-effect reported. The results were such that continuation of treatment with isosorbide mononitrate after the trial was recommended by the attending physician in 77% of the hospital patients and 87% of the general practice patients.