Comparison of 50-mg and 100-mg sustained-release isosorbide mononitrate in the treatment of stable angina pectoris:Effects on quality-of-life indices

High-dosage nitrates are more effective for the management of anginal symptoms but produce more adverse effects, including development of tolerance and the zero-hour effect (rebound angina at the end of the dosing interval). Such effects may reduce the beneficial effect of treatment on quality of life. In a self-controlled, 6-month study, the effects on symptoms and quality of life of 50 mg and 100 mg sustained-release isosorbide mononitrate (SR ISMN), administered once daily, on anginal symptoms and quality of life (QOL) were assessed in 453 patients with stable angina pectoris. QOL was assessed by means of a test battery based on the Medical Outcomes Short-Form 36 Health Survey and the Angina Pectoris Quality of Life Questionnaire. The internal consistency and reliability of the multiitem scales were estimated by use of Cronbach's alpha coefficient. Based on their improvements in New York Heart Association (NYHA) angina classification, patients who received 100 mg daily showed greater improvement than those who received 50 mg daily; the mean difference between treatments was consistent with a significantly greater improvement of mobility and angina indices. Adverse effects, as estimated by side-effect index, including rebound angina at times of rest, and by patient compliance rating, differed slightly between the two treatment regimens and were even less problematic with the higher dosage than with the lower dosage. Psychological distress index and life satisfaction scores also were significantly higher with 100 mg than with 50 mg daily. The results of this study suggest that SR ISMN 100 mg once daily provided a better NYHA angina classification than SR ISMN 50 mg did and did not produce further adverse effects. In addition SR ISMN 100 mg improved various QOL indices more than SR ISMN 50 mg did, particularly the mobility index and certain life satisfaction scores, which are the most important indicators of QOL in this category of patients.