Twinblok Trio ER

Metoprolol is a cardioselective beta-blocker medication that primarily blocks beta-1 adrenergic receptors in the heart to reduce heart rate, contractility, and blood pressure, thereby treating conditions such as hypertension, angina pectoris, heart failure, and certain arrhythmias.[1] It is available in immediate-release (metoprolol tartrate) and extended-release (metoprolol succinate) formulations for oral administration,[1] as well as an intravenous form for acute settings like reducing mortality risk post-myocardial infarction.[2] First approved by the FDA in 1978 under the brand name Lopressor, metoprolol is widely prescribed alone or in combination with other agents and is noted for its relatively favorable side effect profile compared to non-selective beta-blockers, though it can cause bradycardia, fatigue, and bronchospasm in susceptible individuals.[3][1]