Controlled release isosorbide-5-mononitrate in angina pectoris: a comparison with standard formulation isosorbide dinitrate.

In a randomized, double-blind, placebo controlled, crossover study, the antianginal and anti-ischemic effects of a controlled release formulation of isosorbide-5-mononitrate 60 mg once daily and of a standard formulation of isosorbide dinitrate 30 mg qid, were assessed during the first day of treatment and after seven days of sustained therapy. In comparison to placebo, the acute administration of isosorbide-5-mononitrate increased treadmill walking time at 4 and 8 h, and isosorbide dinitrate prolonged treadmill walking time when tested at 4 h after each of the first three doses. During sustained therapy, isosorbide dinitrate produced no significant changes over placebo values. Isosorbide-5-mononitrate prolonged treadmill walking time 4, 8 and 12 h after morning dosing by 54, 41 and 52 s, but these changes were not significant compared to placebo. Treadmill walking time was, however, significantly greater at 4 and 12 h during isosorbide-5-mononitrate therapy compared with isosorbide dinitrate. There was no significant difference in treadmill walking time during acute and sustained therapy with isosorbide-5-mononitrate indicating a lack of tolerance; there was a complete loss of effect during sustained qid therapy with isosorbide dinitrate.