isossorbida

Isossorbida refers to a group of organic nitrates derived from isosorbide, most commonly isosorbide dinitrate (ISDN) and isosorbide mononitrate (ISMN). These drugs are vasodilators used to prevent and treat angina pectoris and may be used as part of combination therapy for heart failure in certain regimens. They release nitric oxide in vascular smooth muscle, activating guanylate cyclase and increasing cyclic GMP, which promotes relaxation of veins and arteries.

In clinical use, isosorbide dinitrate is often employed for rapid or intermittent relief of angina, whereas isosorbide mononitrate is favored for long-acting, once- or twice-daily prophylaxis due to its more favorable pharmacokinetic profile. The primary hemodynamic effect is a reduction in venous return (preload), with arterial dilation at higher doses that can lower systemic resistance (afterload). This combination reduces myocardial oxygen demand and improves exercise tolerance. A portion of ISDN undergoes significant first-pass metabolism, contributing to variable oral bioavailability; ISMN generally has higher and more predictable bioavailability.

Important considerations include tolerance with continuous exposure, necessitating nitrate-free intervals to maintain efficacy. Potential adverse effects are headaches, dizziness, flushing, and hypotension. Interactions with phosphodiesterase-5 inhibitors can cause severe hypotension and are contraindicated. Cautions also apply to concomitant use with other vasodilators and in patients with volume depletion or severe aortic stenosis.

Isossorbida and its salts are widely used in angina management but require monitoring of blood pressure and avoidance of abrupt dose changes without medical guidance.