The acute and chronic efficacy of slow-release isosorbide-5-mononitrate (IS-5-MN) in the form of Elantan long capsules (50 mg) and the tolerability to this agent were evaluated in an open study of 45 patients with chronic stable angina pectoris, treated for one year. After 3 days of replacement of previous antianginal treatment with placebo, an Elantan long capsule (50 mg) was given once daily in the morning. Exercise test was performed 6 hours after ingestion of the capsule, on placebo (after wash-out of 3 days), in the first day of treatment, and after 3 and 6 months of treatment as well as 6 and 24 hours after 12 months of treatment compared to the exercise test at the same time after discontinuation of treatment (three days on placebo). At comparable work load the drug was associated with a 26.6% reduction in ST-segment depression after 6 hours of acute treatment, 46.7% after 3 months of treatment, 52.2% after 6 months, and 66% at the end of treatment (12 months) (P less than 0.001). Even 24 hours after intake of the last capsule of Elantan long the ST-segment reduction was still 49.5%. Exercise test 24 hours after ingestion of the drug revealed that the effect still exists. In the post-treatment placebo period all values returned to pretreatment levels. The sublingual nitroglycerin consumption was reduced by 90% and the frequency of anginal attacks was reduced from 19 +/- 15 to 1.1 +/- 4.2 weekly (P less than 0.001). The drug was well tolerated.(ABSTRACT TRUNCATED AT 250 WORDS)

The antianginal effect and tolerability of isosorbide mononitrate (ISMN), 20 mg 2–3 times daily, orally were investigated in an open study in 28 patients, suffering from coronary heart disease and stable angina pectoris. Ergometric exercise tests were carried out before treatment and 2 h after drug intake, every 3 months during the first year and at 6-month intervals during the following 2 years. At the conclusion of the 3-year study the reduction of ST-segment depression, which had amounted to 58% after 1 year, could be improved to 78% (p < 0.01). The frequency of angina was markedly reduced during the treatment with ISMN. While 14 of the patients had more than 3 episodes per day prior to the study, 16 patients were symptom-free at the end of the three years’ therapy, and none of the patients had more than 1 or 2 attacks per day. The consumption of sublingual nitroglycerin diminished by 94% after one year and by 98% after 3 years of therapy (p < 0.01). Headache was the only adverse effect observed in some of the patients (at the initiation of the treatment only). In conclusion this study demonstrated (1) the good tolerability of ISMN, at the doses used, and (2) the fact that the antianginal efficacy may be enhanced during the course of the therapy.