Clinical effects of a sustained-release preparation of isosorbide dinitrate on angina pectoris

The antianginal action of a sustained-release preparation of isosorbide dinitrate (SUS-ID), administered twice a day, was examined in open trial in 61 patients with angina pectoris. The results obtained were as follows: 1) The frequency of anginal attacks as well as consumption of nitroglycerin tablets began to decrease significantly in the two weeks following the commencement of treatment with SUS-ID; increasing the dose and prolonging the period of administration resulted in further augmentation of its clinical effect. 2) The subjective symptoms improved in 44 of the 61 patients studied (72.1%), and 17 patients (27.9%) showed an improved electrocardiogram. 3) Both the systolic and diastolic blood pressures were significantly lowered, but little change in heart rate was observed. 4) According to the efficacy assessment by the doctors in charge, this drug was judged to be "effective and strongly recommendable" and to be "usable" in 56 of 61 patients (91.8%). Thus SUS-ID was considered to be of clinical usefulness. 5) In terms of side effects, 14 patients (23.0%) complained of headache and three patients (4.9%) of dizziness. These side effects, however, were not serious enough to cause withdrawal of the drug.