Educational use only. Drug cards are AI-assisted study material for NCLEX preparation.
Metoprolol (Lopressor, Toprol XL)
Mechanism of action
Selectively blocks β1 receptors in the heart, lowering heart rate, contractility, and AV nodal conduction. The result is reduced cardiac workload and oxygen demand. Used for hypertension, angina, post-MI mortality reduction, heart failure (carvedilol or metoprolol succinate XL), and rate control in atrial fibrillation.
Adverse effects
Life-threatening / NCLEX-tested
- Severe bradycardia and heart block
- Worsening heart failure if started during decompensation (start low, go slow)
- Bronchospasm in asthma — selectivity is dose-dependent and lost at high doses
- Profound hypotension when stacked with calcium channel blockers (especially diltiazem/verapamil)
- Mask hypoglycemia symptoms in diabetics (the tachycardia warning sign is blunted)
- Abrupt withdrawal can cause rebound hypertension, angina, or MI
Side effects
Common — what to teach
- Fatigue and exercise intolerance
- Cold hands and feet
- Dizziness, lightheadedness
- Vivid dreams or sleep disturbance
- Erectile dysfunction
- Depressed mood
Food & drug interactions
Calcium channel blockers (especially non-dihydropyridines like diltiazem and verapamil) compound bradycardia and AV block — combined IV use is dangerous. Digoxin compounds AV blockade. Insulin and oral hypoglycemics: metoprolol can mask hypoglycemia. NSAIDs blunt the antihypertensive effect. Avoid abrupt discontinuation — taper over 1–2 weeks.
Nursing implications
Assessment, monitoring, patient teaching
- Check apical pulse and BP before every dose; hold for HR < 60 or SBP < 100 unless ordered otherwise
- Teach patients NEVER to stop abruptly — rebound MI/angina/HTN is real
- For heart failure, use metoprolol succinate XL (Toprol XL) and titrate slowly; transient worsening can occur in the first 2 weeks
- Counsel diabetic patients that the usual tachycardia warning of hypoglycemia will be blunted — rely on sweating, hunger, confusion, glucose checks
- Take with or right after food to improve absorption
- Watch for fluid retention, weight gain, or worsening dyspnea — early signs of HF decompensation
When to hold / contraindications
- HR < 60 bpm
- SBP < 100 mmHg (or per provider parameters)
- Second- or third-degree AV block
- Acute decompensated heart failure
- Severe asthma exacerbation
Memory anchor
Beta blockers end in "-olol" — "hold at 60 / 100" (HR 60, SBP 100). Cardioselective at low doses, loses selectivity at high. Never stop cold-turkey.
Practice Metoprolol questions
Test your recall on real NCLEX-style pharmacology questions — with full rationales and an AI Coach for the parts you miss.