Pharmacology of Adrenergic and Anti-Adrenergic Drugs

Mechanism of Action of Anti-Adrenergic Drugs

Anti-adrenergic drugs work by blocking adrenergic receptors or inhibiting the synthesis/release of catecholamines. These drugs are classified into alpha-blockers, beta-blockers, and mixed adrenergic antagonists.

1. Alpha-Blockers

Alpha-blockers inhibit the effects of norepinephrine on alpha-adrenergic receptors, leading to vasodilation and reduced blood pressure.

• Used in hypertension and benign prostatic hyperplasia.
• Common drugs: Prazosin, Doxazosin, Terazosin.

2. Beta-Blockers

Beta-blockers act by preventing the binding of epinephrine and norepinephrine to beta-receptors, reducing heart rate and blood pressure.

• Used for hypertension, arrhythmias, and heart failure.
• Common drugs: Propranolol, Atenolol, Metoprolol.

3. Mixed Adrenergic Antagonists

These drugs block both alpha and beta receptors, leading to a broader range of cardiovascular effects.

• Used in severe hypertension and heart failure.
• Common drugs: Labetalol, Carvedilol.

Adverse Effects and Considerations

Common adverse effects include hypotension, bradycardia, dizziness, and fatigue. It is essential to monitor patients for these effects.