Beta-blockers are a class of medication that block the effects of adrenaline (epinephrine) on the heart and blood vessels by occupying beta-adrenergic receptors. This slows the heart rate, reduces the force of the heart’s contractions, lowers blood pressure, and reduces the electrical irritability of the heart muscle.
In cardiac care, beta-blockers are prescribed for a wide range of conditions. After cardiac arrest, they are commonly used to suppress arrhythmias, protect the heart muscle, and reduce the risk of a further event. They are a cornerstone of treatment in [heart failure](/glossary/heart-failure/) with reduced ejection fraction, and are specifically indicated in conditions including [Long QT Syndrome](/glossary/long-qt-syndrome/), [hypertrophic cardiomyopathy](/glossary/hypertrophic-cardiomyopathy/), and [CPVT](/glossary/catecholaminergic-polymorphic-ventricular-tachycardia/). They are also occasionally used to manage the physical symptoms of anxiety in cardiac survivors.
Cardioselective beta-blockers (such as bisoprolol and metoprolol) primarily target the heart, with less effect on the airways, making them preferable in patients with asthma or COPD. Non-selective types (such as carvedilol and propranolol) also affect blood vessels and are used in specific circumstances.
Common side effects include fatigue, cold hands and feet, reduced exercise tolerance, and in some cases sleep disturbance or low mood. Beta-blockers blunt the heart rate response to exercise, which is important to account for during [cardiac rehabilitation](/glossary/cardiac-rehabilitation/). They should not be stopped suddenly without medical guidance, as abrupt withdrawal can provoke rebound arrhythmias.
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