Selective β1-adrenoceptor blockers
ATC code: C07AB02 (Metoprolol)
Cardioselective β1-blocker without intrinsic sympathomimetic activity. Reduces heart rate, contractility and cardiac output and slows AV conduction. Lowers myocardial oxygen demand and has antiarrhythmic and antihypertensive effects. Metabolized by CYP2D6 – exposure is 2–5-fold higher in poor metabolizers.
First line
Beta-blockers are first-line in stable angina. Metoprolol reduces heart rate and myocardial oxygen consumption, decreasing angina attack frequency. After MI, beta-blockers reduce the risk of recurrent MI and sudden death. Target resting heart rate is 55-60 bpm.
First line
Metoprolol succinate is one of three beta-blockers proven to reduce mortality in HFrEF. The MERIT-HF trial demonstrated a 34% reduction in all-cause mortality. Start at 12.5-25 mg daily, titrate every 2 weeks to target dose of 200 mg. Succinate must not be substituted with tartrate – they are not equivalent in HF. 2021 includes metoprolol succinate among recommended beta-blockers for HF.
Only metoprolol succinate (extended-release form). Tartrate is not used in HF – no evidence base.
First line
Metoprolol is one of the first-choice agents for heart rate control and prevention of supraventricular tachycardia paroxysms. In acute SVT, metoprolol is given intravenously 5 mg over 2 minutes, repeatable up to 3 times at 5-minute intervals. Oral form is used for long-term prevention.
Individual decision
Beta-blockers as antihypertensive monotherapy in the absence of CAD, HF, tachyarrhythmia, or post-MI status are not first-line per 2024, 2017, and NG136. Metoprolol is prescribed in concurrent CAD, post-MI, or tachyarrhythmias. Less effective for stroke prevention than ACEi/ARB, CCB, or diuretics. Tartrate 50–100 mg twice daily or succinate 50–200 mg once daily. In younger patients without a compelling indication, other classes are preferred.
The drug is promoted for these uses outside international guidelines. Each entry below is analyzed against AEMPS, FDA, EMA, Cochrane and major RCTs.
Not recommended
Metoprolol is a selective β1-adrenergic blocker. It is prescribed for hypertension, ischemic heart disease, heart failure, arrhythmias, and after myocardial infarction ( 2023, SEH-LELHA, 2017). In anti-aging regimens, metoprolol is taken to relax and lower heart rate in healthy normotensives. In people with normal blood pressure and no ischemic heart disease, no clinical studies of prophylactic use exist. The drug causes bradycardia, hypotension, fatigue, bronchospasm, and a withdrawal syndrome on abrupt discontinuation. If metoprolol was prescribed to a healthy person, consider seeking a second opinion.
15 pairs found. Sorted from critical to minor.
Mechanism
Dual mechanism. Amiodarone non-competitively blocks β-adrenoceptors and depresses atrioventricular (AV) conduction; metoprolol is a competitive β-blocker. Effects add up: lowered heart rate and AV conduction. Amiodarone also inhibits CYP2D6 and metoprolol plasma levels rise.
Symptoms
Bradycardia (heart rate below 50/min), dizziness, syncope. ECG: first- to second-degree AV block, prolonged PR. In heart failure: worsening dyspnoea and oedema.
Management
The combination is appropriate in cardiology (atrial fibrillation, post-infarction care). Halve the metoprolol dose when starting amiodarone. Check pulse and ECG at 1 and 4 weeks. If pulse drops below 50 or second-degree AV block appears, adjust metoprolol further.
Sources
Mechanism
Bupropion is a potent CYP2D6 inhibitor, the main metoprolol metabolic route. Metoprolol plasma levels rise 4- to 5-fold. Risk of marked bradycardia and hypotension emerges.
Symptoms
Bradycardia (heart rate below 50/min), dizziness, syncope, orthostatic hypotension. In heart failure: worsening dyspnoea and oedema.
Management
Reduce metoprolol 2- to 3-fold when combined; monitor pulse and blood pressure. Alternative beta-blockers without CYP2D6 dependence: bisoprolol or carvedilol.
Mechanism
Abrupt clonidine withdrawal on a beta-blocker triggers a hypertensive crisis: the α2 effect is lost while β-blockade persists – an 'unopposed' α1 effect develops with a sharp blood pressure rise. Additional additive bradycardia.
Symptoms
Abrupt clonidine withdrawal causes hypertensive crisis: sharp blood pressure rise, headache, tachycardia, anxiety, sweating. Symptoms appear 18–24 hours after a missed clonidine dose.
Management
For planned clonidine withdrawal, stop metoprolol 3–7 days beforehand, then taper clonidine over 1–2 weeks. Alternative antihypertensives: an ACE-I (enalapril) plus amlodipine without clonidine.
Mechanism
Additive slowing of atrioventricular (AV) conduction and lowered heart rate. In atrial fibrillation this synergistic ventricular rate control is standard; without atrial fibrillation, bradycardia and AV block risks rise.
Symptoms
Bradycardia (heart rate below 50/min), dizziness, syncope. ECG: first- to second-degree AV block, prolonged PR. Older patients: fatigue, weakness.
Management
The combination is appropriate in atrial fibrillation with preserved or reduced ejection fraction. Check pulse and ECG at 1 and 4 weeks. If pulse drops below 50 or second-degree AV block appears, reduce metoprolol; if symptoms persist, hold digoxin temporarily.
Sources
Mechanism
Non-dihydropyridine calcium channel blocker (diltiazem) + beta-blocker (metoprolol) – additive AV node blockade and negative inotropic effect. Diltiazem also raises metoprolol levels via a minor CYP route.
Symptoms
Bradycardia (heart rate below 50/min), dizziness, syncope. ECG: first- to second-degree AV block. Older patients: fall risk.
Management
Avoid the combination. For atrial fibrillation rate control: metoprolol + digoxin (without diltiazem) or diltiazem with metoprolol withdrawn. Alternative beta-blockers without CYP2D6 dependence: bisoprolol or carvedilol.
Mechanism
Fluoxetine is a potent CYP2D6 inhibitor, the main metoprolol metabolic route. Metoprolol plasma levels rise 4- to 5-fold. Risk of marked bradycardia, hypotension, and AV block emerges.
Symptoms
Bradycardia (heart rate below 50/min), dizziness, syncope, orthostatic hypotension. In heart failure: worsening dyspnoea and oedema.
Management
Reduce metoprolol 2- to 3-fold when combined; monitor pulse and blood pressure. Alternative beta-blockers without CYP2D6 dependence: bisoprolol or carvedilol. Alternative antidepressants without CYP2D6 inhibition: sertraline or escitalopram.
Mechanism
Non-dihydropyridine calcium channel blocker (verapamil) + beta-blocker (metoprolol) – additive AV node blockade and negative inotropic effect. Verapamil also blocks CYP2D6 and raises metoprolol plasma levels.
Symptoms
Bradycardia (heart rate below 50/min), dizziness, syncope. ECG: first- to second-degree AV block. Older patients: fall risk.
Management
Avoid the combination. For atrial fibrillation rate control: metoprolol + digoxin (without verapamil) or verapamil with metoprolol withdrawn. Alternative beta-blockers without CYP2D6 dependence: bisoprolol or carvedilol.
Mechanism
Additive bradycardia and sedation. Fall risk in older patients.
Symptoms
Lower blood pressure, postural dizziness, fatigue. Older patients: fall risk.
Management
In older patients, check pulse and blood pressure 1–2 weeks after starting alprazolam. Alternative anxiolytic: hydroxyzine or a short lorazepam course.
Mechanism
Amitriptyline is a CYP2D6 substrate, as is metoprolol. Enzyme competition raises both drug levels. Plus additive anticholinergic effect on the heart (bradycardia, PR prolongation).
Symptoms
Bradycardia (heart rate below 50/min), dizziness, syncope. ECG: PR prolongation. Older patients: delirium and fall risk.
Management
In older patients, check pulse and ECG 1–2 weeks after starting amitriptyline. Alternative beta-blocker without CYP2D6 dependence: bisoprolol or carvedilol. For neuropathic pain, alternative: gabapentin or pregabalin.
Mechanism
Target combination in angina and hypertension. Amlodipine dilates vessels; metoprolol slows heart rate. The drugs compensate each other's reflex effects.
Symptoms
Lower blood pressure, postural dizziness, fatigue. Older patients: fall risk.
Management
Standard combination in ischaemic heart disease with hypertension. Check pulse and blood pressure 1–2 weeks after start. In patients with ejection fraction below 40%, watch for heart failure decompensation.
Sources
Mechanism
Metoprolol is mainly metabolised by CYP2D6; clarithromycin does not clinically significantly inhibit CYP2D6. The effect on metoprolol levels is minimal. Additive bradycardia is possible from clarithromycin's direct effect on the cardiac conduction system.
Symptoms
Bradycardia, dizziness, fatigue. Symptoms appear during clarithromycin courses in older patients and concurrent heart failure.
Management
For short clarithromycin courses (7–14 days) with normal heart rate, no adjustment needed. In older patients and prior first-degree AV block, check ECG at one week. For long-term clarithromycin (e.g. Mycobacterium avium complex), antibiotic alternative: azithromycin (minimal HR effect).
Mechanism
Target combination in heart failure with reduced ejection fraction and in arterial hypertension. Synergistic reduction of blood pressure, preload, and afterload.
Symptoms
On starting, in older or hypovolaemic patients: symptomatic hypotension, dizziness, fatigue. Metoprolol bradycardia is amplified as sympathetic activation drops.
Management
Start both drugs at minimal doses with up-titration every 2 weeks to target. Check standing/sitting BP, heart rate, creatinine and potassium at 2 weeks. In heart failure, the goal is maximum tolerated dose; the RCT evidence base is extensive.
Sources
Mechanism
Target combination in heart failure and arterial hypertension. Synergistic blood pressure reduction. The ARB does not mask the adrenergic response to hypoglycaemia.
Symptoms
On starting, in older patients: symptomatic hypotension, dizziness. Metoprolol bradycardia is amplified as sympathetic activation drops.
Management
Start both at minimal doses with up-titration every 2 weeks to target. Check standing/sitting BP, heart rate, creatinine and potassium at 2 weeks. In diabetes, monitor for hypoglycaemia: metoprolol is cardioselective and weakly masks adrenergic symptoms.
Sources
Mechanism
Metoprolol is cardioselective but at high doses antagonises theophylline's bronchodilator effect. In bronchial asthma, control may worsen.
Symptoms
Exertional dyspnoea, wheezing, more frequent asthma attacks. In COPD: symptom exacerbation.
Management
In asthma and COPD with atrial fibrillation or hypertension, metoprolol is preferred at cardioselective doses (up to 100 mg/day) under pulmonary function monitoring. In severe asthma, consider alternatives — diltiazem or verapamil for rate control in atrial fibrillation. Theophylline is second-line in COPD; consider switching to long-acting beta-2 agonists (formoterol).
Mechanism
Paracetamol is metabolised by CYP2E1 (5%) and predominantly by glucuronidation; metoprolol by CYP2D6. No direct pharmacokinetic interaction.
Symptoms
The combination usually causes no specific symptoms. Each drug's individual side effects remain.
Management
No dose adjustment needed. Paracetamol remains the analgesic of choice in patients on metoprolol.
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FDA category C. Beta-blockers can cause fetal growth restriction, neonatal bradycardia, and hypoglycemia. If antihypertensive therapy is needed in pregnancy, labetalol or methyldopa are preferred.
Compatible. Hale L3. RID 1.4%. High M/P (3.0), but short T½ prevents accumulation. Monitor infant for bradycardia and poor feeding. Suitable for maternal CHD.
Reference information, not a clinical decision. Discuss feeding pauses or changes with your physician or an IBCLC.
Metoprolol is evaluated for the following indications with varying evidence strength: Coronary artery disease (evidence tier A), Supraventricular tachycardia (evidence tier A), Heart failure (evidence tier A). See the full indication matrix with dosing and citations above on this page.
Common side effects of Metoprolol (≥ 1 in 100): Bradycardia, Hypotension, Fatigue, weakness, Dizziness, Cold extremities. See the Safety section for uncommon and serious reactions.
FDA category C. FDA category C. Beta-blockers can cause fetal growth restriction, neonatal bradycardia, and hypoglycemia. If antihypertensive therapy is needed in pregnancy, labetalol or methyldopa are preferred.
Compatible. Hale L3. RID 1.4%. High M/P (3.0), but short T½ prevents accumulation. Monitor infant for bradycardia and poor feeding. Suitable for maternal CHD.
Metoprolol is contraindicated in: Second- or third-degree AV block without a pacemaker; Sick sinus syndrome without a pacemaker; Severe bradycardia (HR below 50 bpm before treatment); Severe bronchial asthma; Decompensated heart failure with pulmonary edema or cardiogenic shock. Full list in the Safety section.