Pharmacotherapeutic group: Anti-anginal Agent.
Pharmacology: Isosorbide, a nitrate, relaxes vascular smooth muscle. The efficacy of nitrates in alleviating the pain of angina pectoris is probably due to a reduction in myocardial oxygen demand rather than to an increase in myocardial oxygen supply. Although venous effects predominate, nitrates dilate both arterial and venous beds. Dilating the post-capillary vessels, including large veins, promotes a peripheral pooling of blood and decreases venous return to the heart. This reduces left ventricular end-diastolic pressure (pre-load). The arteriolar relaxation reduces systemic vascular resistance and arterial pressure (after-load), and decrease in ventricular volume reduces intramyocardial tension and lessens myocardial oxygen demand.
After a single oral dose of 30 mg isosorbide, mean plasma peak concentrations of 24 ng/ml were observed within 30 minutes.