Isosorbide mononitrate 60mg modified-release capsules

Isosorbide mononitrate is an anti-anginal agent and vasodilator that relaxes vascular smooth muscle to prevent and manage angina pectoris. The pharmacological action is mediated by the active metabolite, [nitric oxide], which is released when isosorbide mononitrate is metabolized.T28 Nitric oxide works on both arteries and veins, but predominantly veins: by relaxing veins and reducing the central venous pressure, nitric oxide causes venous pooling and a decrease in the venous return to the heart, thus decreasing cardiac preload.[L11743] In healthy subjects, the stroke volume is decreased and venous pooling can occur in the standing posture, leading to postural hypotension and dizziness.T28

At therapeutic doses of isosorbide mononitrate, nitric oxide has a bigger effect on larger muscular arteries over small resistance arteries. Arterial relaxation leads to reduced systemic vascular resistance and systolic blood (aortic) pressure, decreasing to decreased cardiac afterload.[L11743,T28] The direct dilator effect on coronary arteries opposes the coronary artery spasm in variant angina or angina pectoris.T28 At larger doses, nitric oxide causes the resistance arteries and arterioles to dilate, reducing arterial pressure via coronary vasodilatation. This leads to increased coronary blood flow.[L11743,T28] Reduced cardiac preload and afterload caused by nitric oxide causes a reduction in myocardial oxygen consumption; decreased myocardial oxygen demand, along with increased coronary blood flow, leads to an increased in the oxygen content of coronary sinus blood T28 and the relief from ischemia.[L11743]

The end effect of isosorbide mononitrate include decreased cardiac oxygen consumption, redistribution coronary flow toward ischemic areas via collaterals, and the relief of coronary spasms. Nitric oxide can also increase the rate of relaxation of cardiac muscles, which is an effect outside of vascular smooth muscles.T28 Organic nitrates can also relax other types of smooth muscles, including esophageal and biliary smooth muscle.T28 The anti-anginal activity of isosorbide mononitrate was observed about 1 hour after dosing, and the peak effect was achieved from 1-4 hours after dosing.[L11698] The duration of anti-anginal action of at least 12 hours was observed with an asymmetrical dosing regimen.[A190738]