Lopresor OROS / Metoprolol Fumarate | 80274-67-5

Metoprolol Fumarate is the fumarate salt form of metoprolol, a cardioselective competitive beta-1 adrenergic receptor antagonist that lacks intrinsic sympathomimetic activity and possesses antihypertensive properties. It exerts its effects by antagonizing beta-1 adrenergic receptors in the myocardium, thereby reducing the rate and force of myocardial contraction and decreasing cardiac output. Additionally, metoprolol fumarate may lower renin secretion, leading to reduced levels of angiotensin II, which helps prevent vasoconstriction and aldosterone secretion. It is commonly used in the management of cardiovascular conditions such as hypertension, angina, heart failure, and arrhythmias, and is available in immediate- or extended-release formulations. Common side effects include fatigue, dizziness, bradycardia, and hypotension, and it should be withdrawn gradually to avoid rebound effects. The typical starting dose is 25–50 mg daily, with a maximum of up to 200–400 mg daily in divided doses, depending on patient tolerance and clinical response.