Carvedilol

Carvedilol is a non-selective beta-adrenergic blocker with alpha-1 blocking activity, used to treat cardiovascular conditions. It is marketed as immediate-release and extended-release formulations under brand names such as Coreg and Coreg CR and is available by prescription.

Mechanism of action and properties: Carvedilol reduces heart rate, decreases myocardial contractility, and lowers peripheral vascular resistance through alpha-1 blockade. These effects together reduce myocardial oxygen demand and afterload. The drug is administered as a racemic mixture; the S(-) enantiomer provides most beta-blocking activity, while both enantiomers contribute to alpha-1 blockade. Antioxidant properties have also been described.

Indications: It is approved for essential hypertension, chronic heart failure with reduced ejection fraction, and to reduce cardiovascular mortality after acute myocardial infarction in certain patients. In heart failure, carvedilol is typically used in addition to standard therapies and titrated to tolerability.

Dosing, pharmacokinetics, and administration: Carvedilol is taken orally, with dosing adjusted gradually to minimize adverse effects. It is extensively metabolized by the liver, with relatively low bioavailability due to first-pass metabolism. Peak concentrations occur within hours of dosing, and the product has an approximate half-life of 6–12 hours, often requiring twice-daily or once-daily regimens depending on the formulation.

Adverse effects and interactions: Common adverse effects include dizziness, fatigue, bradycardia, hypotension, and edema. It can provoke bronchospasm in patients with asthma or COPD, and may mask signs of hypoglycemia in people with diabetes. Interactions with other antihypertensives, calcium channel blockers, and drugs affecting hepatic enzymes (CYP2D6, CYP2C9) should be considered.

Contraindications and cautions: Severe bradycardia, advanced AV block without a functioning pacemaker, decompensated heart failure requiring intravenous inotropes, cardiogenic shock, and severe hepatic impairment are contraindications. Caution is advised in patients with bronchospastic disease, hypotension, or significant conduction abnormalities.