Isosorbide mononitrate 30% immediate-release 70% sustained-release formulation: a review. DUMQOL (DUtch Mononitrate Quality of Life) Study Group.

Since the first publication of isosorbide mononitrate 30% immediate-release 70% sustained-release (IR-SR) formulation in 1985, a considerable body of literature concerning its clinical efficacy and safety has become available. Theoretically, the formulation has the advantage over conventional isosorbide mononitrate or dinitrate (ISMN/ISDN) that it has a simpler and more predictable pharmacokinetic profile. The objectives of this paper are to review published data so far and to see whether the theoretical advantages translate into better clinical effectiveness. 1. After oral administration, isosorbide mononitrate IR-SR has a rapid onset of action (30 minutes), and effects are evident for up to 17 hours. 2. The antianginal effects of once-daily isosorbide mononitrate IR-SR increased with increasing dosages, were generally larger than those of either placebo or equipotent doses of conventional ISMN/ISDN, and were somewhat larger than those of the beta blocker bupranolol. The effects were generally similar to those of sustained release nifedipine. 3. Patients showed significantly greater improvement in some quality-of-life indices with once-daily isosorbide mononitrate IR-SR than with twice or three times daily regimens of conventional ISMN/ISDN. This was particularly so with mobility, psychological distress, and life satisfaction indices. 4. Tolerance did not develop after 13 months of once daily isosorbide dinitrate IR-SR. No rebound increase in incidence of ischemic episodes was observed after discontinuation of treatment. 5. Long-term efficacy data both of isosorbide mononitrate IR-SR and of conventional ISMN/ISDN are limited so far. Large studies in patients with angina pectoris and patients with heart failure addressing long-term effects are ongoing, and some of the data will be completed within the next months. Isosorbide mononitrate IR-SR has a rapid onset of action and has been shown to be clinically efficient and, in addition, to be more so than conventional ISMN / ISDN. Nitrate tolerance with continued use of the formulation has not yet been reported. Long-term effects on morbidity and mortality are currently being assessed.