Beetasalpaat

Beetasalpaat, or beta blockers, are a class of medications that block beta-adrenergic receptors, reducing the effects of adrenaline and other catecholamines. They can be non-selective, blocking both beta-1 and beta-2 receptors (for example propranolol, nadolol) or beta-1 selective (metoprolol, atenolol, bisoprolol). Some agents have additional properties, such as intrinsic sympathomimetic activity or vasodilating effects (carvedilol, labetalol).

Mechanism of action: by antagonizing beta-adrenergic receptors, they decrease heart rate and contractility, lower blood pressure, slow AV node conduction, and reduce renin release from the kidneys, contributing to antihypertensive effects.

Indications: management of hypertension, angina pectoris, certain arrhythmias, and heart failure with reduced ejection fraction. They are also used for post-myocardial infarction secondary prevention, migraine prophylaxis (e.g., propranolol), and some anxiety-related symptoms.

Pharmacokinetics and administration: available orally and by intravenous infusion; bioavailability and half-lives vary by drug. Dosing must be individualized; abrupt withdrawal can worsen angina or precipitate arrhythmias.

Adverse effects: bradycardia, fatigue, dizziness, and hypotension are common; non-selective agents can provoke bronchospasm in asthma or COPD; may mask signs of hypoglycemia in diabetics; sexual dysfunction.

Contraindications and cautions: acute decompensated heart failure, severe bradycardia, heart block without a pacemaker, uncontrolled asthma or severe COPD; caution in diabetics and patients taking other negative chronotropes.

History: developed in the mid-20th century with contributions from researchers such as James Black; beta blockers are now a widely used therapeutic class.