Metoprolol Succinate
Metoprolol Succinate is a selective beta-1 adrenergic receptor blocker primarily used in the management of cardiovascular conditions. It is the extended-release formulation of metoprolol, offering once-daily dosing for consistent therapeutic effects.
Mechanism of Action:
- Selectively blocks beta-1 adrenergic receptors in the heart, reducing:
- Heart rate (negative chronotropy).
- Myocardial contractility (negative inotropy).
- Cardiac output and oxygen demand.
- Reduces sympathetic nervous system stimulation, improving outcomes in cardiovascular conditions.
- Recommended Usage
Indications:
- Hypertension: Lowers blood pressure, reducing the risk of cardiovascular events.
- Angina Pectoris: Improves exercise tolerance and reduces anginal episodes.
- Heart Failure: Used in stable, symptomatic heart failure with reduced ejection fraction.
- Myocardial Infarction: Reduces mortality and recurrence risk.
- Arrhythmias: Effective in treating atrial fibrillation, supraventricular tachycardia, and ventricular arrhythmias.
- Migraine Prophylaxis (off-label).
Dosage and Administration:
Administer orally, once daily. Individualize dose based on clinical response.
- Hypertension:
- Initial dose: 25–100 mg once daily.
- Maximum dose: 400 mg/day.
- Angina Pectoris:
- Initial dose: 100 mg once daily.
- Maximum dose: 400 mg/day.
- Heart Failure (NYHA Class II–III):
- Initial dose: 12.5–25 mg once daily.
- Gradually titrate every 2 weeks to a target dose of 200 mg once daily, based on tolerance.
- Post-Myocardial Infarction:
- 100–200 mg once daily.
- Arrhythmias:
- Typical dose: 50–100 mg once daily (adjust as needed).
Precautions:
- Contraindications:
- Severe bradycardia, heart block greater than first degree (without a pacemaker).
- Decompensated heart failure.
- Caution in:
- Diabetes: May mask symptoms of hypoglycemia.
- Asthma/COPD: Higher doses may affect beta-2 receptors and worsen bronchospasm.
- Pregnancy and Lactation:
- Category C: Use only if benefits outweigh risks.
- Excreted in breast milk; caution advised during breastfeeding.
- Drug Interactions:
- Additive bradycardia or hypotension with other antihypertensives (e.g., calcium channel blockers, digoxin).
- CYP2D6 inhibitors (e.g., fluoxetine, paroxetine) can increase metoprolol levels.
Key Benefits:
- Beta-1 Selectivity: Reduces cardiovascular effects with minimal impact on bronchial beta-2 receptors, making it safer in respiratory conditions compared to non-selective beta-blockers.
- Once-Daily Dosing: Extended-release formulation ensures consistent blood levels and improved patient compliance.
- Proven Cardiovascular Protection: Reduces mortality in heart failure and post-myocardial infarction patients.
- Symptom Relief: Effective in reducing anginal attacks, arrhythmias, and blood pressure.
