| Drug class |
β1‑selective adrenergic (β‑blocker) |
| Common brand names |
Toprol‑XL, Metoprolol Succinate, Metoprolol ER |
| Typical indications |
• Chronic stable angina
• Hypertension (often part of a multi‑drug regimen)
• Post‑myocardial infarction (to reduce mortality)
• Certain arrhythmias (e.g., supraventricular tachycardia) |
| Pharmacology |
• Blocks β1‑adrenergic receptors in the heart → ↓ heart rate, ↓ contractility, ↓ myocardial O₂ demand.
• ER formulation releases the drug over ~24 h, allowing once‑daily dosing. |
| Standard dosing (adult) |
• 50 mg once daily (often in the morning)
• May be titrated up (usually to 100 mg, 200 mg, 400 mg/day) depending on response and tolerability. |
| Administration |
• Take with a full glass of water.
• Do not crush or chew the tablet—keep the ER coating intact to preserve slow release. |
| Contraindications |
• Severe bradycardia (e.g., second‑ or third‑degree AV block < 60 bpm, unless a pacemaker is implanted)
• Cardiogenic shock
• Severe heart failure (NYHA III/IV)
• Known hypersensitivity to metoprolol or succinate. |
| Common side effects |
• Bradycardia, fatigue, dizziness, light‑headedness
• Cold extremities, nasal congestion, cough (rare)
• Depressed mood or insomnia (some patients) |
| Serious/rare adverse events |
• Severe hypotension, heart block, asthma exacerbation (if β2‑blocked)
• Unmasking of coronary artery disease (if dose escalated too quickly) |
| Drug interactions |
• CYP2D6 inhibitors (e.g., fluoxetine, paroxetine) → ↑ metoprolol levels.
• Calcium channel blockers (verapamil, diltiazem) or digoxin → ↑ risk of bradycardia.
• Other β‑blockers or antiarrhythmics → additive cardiovascular depression. |
| Special populations |
• Elderly: start at lowest dose; watch for orthostatic hypotension.
• Renal or hepatic impairment: dose adjustment may be needed; monitor levels. |
| Monitoring |
• Blood pressure, pulse, ECG (if indicated) at baseline and after dose changes.
• Renal function (creatinine) periodically if on long‑term therapy. |
| Patient counseling points |
• Take the medication at the same time each day to maintain steady blood levels.
• Do not stop abruptly—taper under clinician supervision to avoid rebound tachycardia or angina.
• Watch for symptoms of low blood pressure (dizziness, fainting) and report them. |
| When to seek medical help |
• Persistent dizziness or fainting, chest pain, shortness of breath, palpitations, or swelling of lower extremities. |