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Drug Monograph

Metoprolol

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Metoprolol

Cardioselective Ξ²1 blocker β€” **tartrate (IR)** vs **succinate (ER)**

High YieldAdultBBHFHTN

Indication

HTN β€’ Chronic HFrEF (**succinate ER only**) β€’ Angina β€’ Post-MI β€’ AF rate control β€’ IV acute rate control (monitored setting)

At a glance

INDICATIONS (CORE USE)

**HTN**; **ONLY metoprolol succinate ER is guideline-supported for chronic HFrEF**. **DO NOT use metoprolol tartrate for chronic HFrEF**.

ADULT DOSE (STANDARD)

**PO:** start **low** (e.g. **25–50 mg** tartrate BID or succinate QD) β†’ **titrate** to **HR/BP** and tolerance

MAX DOSE

**Indication-labeled** β€” HF titration targets per cardiology; avoid copying tartrate max onto succinate blindly

Route

Tartrate IR PO; succinate ER PO; IV only for monitored acute rate control

PEDIATRIC DOSE

Specialist-only β€” weight-based when used

Do not miss

Must-not-miss safety points

Major warning

- Bradycardia / AV block β€” hold if symptomatic - Acute decompensated HF β€” **DO NOT start** / **hold** if SBP <90–100, hypoperfusion, cardiogenic shock, or pulmonary edema requiring IV therapy - Abrupt stop after chronic use β†’ rebound HR / ischemia

Indications

USE IF: HTN, chronic HFrEF (**succinate ER only**), angina, AF rate control when Ξ²-blocker appropriate. AVOID IF: symptomatic bradycardia without pacing plan, acute decompensated HF, high-grade AV block, or active hypoperfusion/shock.

Primary

  • Hypertension
  • **ONLY metoprolol succinate ER** is guideline-supported for chronic HFrEF

Secondary

  • Atrial fibrillation / flutter β€” **rate control**
  • Angina / chronic coronary disease (ischemic heart disease context)
  • Post–MI secondary prevention (when Ξ²-blocker indicated)

Other

  • IV boluses for acute rate control in monitored setting only (hemodynamically stable; no acute decompensated HF; no high-grade AV block)

Dosing

STANDARD (ADULT PO)

**ONLY succinate ER for chronic HFrEF**. **DO NOT use tartrate for chronic HFrEF**.

ADULT DOSE

**HF (succinate ER only):** start low, double q2 weeks as tolerated toward target. **DO NOT use tartrate for chronic HFrEF**. **HTN / angina:** start 25–50 mg PO (formulation-specific interval), then titrate to HR/BP. **IV (acute rate control, monitored setting only):** β€’ Use only if hemodynamically stable β€’ Avoid if hypotensive / shock states β€’ Do NOT use in acute decompensated HF β€’ Do NOT use with high-grade AV block β€’ 2.5–5 mg IV over 2–5 min β€’ Repeat every 5 min β€’ Max 15 mg β€’ Continuous HR/BP monitoring

PEDIATRIC DOSE

Rare β€” pediatric cardiology protocols only.

MAX DOSE

Label and indication-specific β€” HF uptitration often **200 mg/day succinate** context (verify clinic target)

Practical Note

**ONLY metoprolol succinate ER is guideline-supported for chronic HFrEF**. **DO NOT use metoprolol tartrate for chronic HFrEF**. DO NOT substitute tartrate ↔ succinate without dose + schedule reconciliation.

Warnings

Clinical warnings

  • Beta1-selective β€” caution in asthma / bronchospasm; not asthma-proof at higher doses. HOLD if HR <50–55, SBP <90–100, symptomatic bradycardia, high-grade AV block, or acute decompensated HF with shock/hypoperfusion.
  • CYP2D6 inhibitors may increase **metoprolol** levels
  • Avoid or use extreme caution with verapamil / diltiazem (especially IV combination): bradycardia, AV block, hypotension, and shock risk

Adverse effects

  • Fatigue
  • bradycardia
  • hypotension
  • bronchospasm (less than non-selective)
  • masked hypoglycemia

Contraindications

  • Cardiogenic shock (acute)
  • Symptomatic sinus bradycardia / sick sinus without pacemaker when pacing not available
  • High-grade AV block (without pacing)
  • Known serious hypersensitivity

Drug interactions

  • Verapamil / diltiazem: avoid or use extreme caution (bradycardia / AV block / hypotension / shock risk)
  • Digoxin: additive AV-node suppression / AV block risk
  • Insulin / sulfonylureas: masks hypoglycemia warning
  • CYP2D6 inhibitors: increased metoprolol exposure

Special populations

Pediatrics

Specialist-only β€” weight-based when used

Pregnancy

Not first-line for pregnancy HTN vs **labetalol** in many regions β€” OB if used. **

Lactation

** generally compatible at usual doses β€” monitor infant if concern.

Renal impairment

Less renally driven than atenolol β€” still reassess in advanced CKD with polypharmacy.

Hepatic impairment

Severe hepatic impairment: START lower and monitor HR/BP closely.

Elderly

**↑ sensitivity** to bradycardia and hypotension β€” conservative start.

Administration

Take **succinate ER** whole; **tartrate** with meals if GI upset β€” follow formulation label.

Monitoring

  • Monitor: - Symptoms β†’ dizziness, syncope, fatigue - Post-dose HR/BP after titration or IV bolus
  • Recheck: - Reassess ECG / PR interval / AV block risk with symptoms, IV use, or dose escalation - Reassess dose / volume / cause within 48–72h after change - If targets not met after reassessment of dose, organ function, and interactions β†’ escalate per protocol (DO NOT continue blindly)
  • Hold if:
    - Hold if:
    - HR <50–55
    - SBP <90–100
    - Symptomatic bradycardia
    - Acute decompensated HF
    - Hypoperfusion / cardiogenic shock
    - Pulmonary edema requiring IV therapy

    Also hold:
    - High-grade AV block
    - Severe orthostasis

Overdose / toxicity

Clinical Picture

A) Mild β†’ bradycardia, hypotension, fatigue B) Moderate β†’ sustained bradycardia + hypotension Β± AV block C) Severe β†’ shock, high-grade AV block, seizures / coma (severe toxicity)

Immediate Actions

β€’ Airway + continuous monitoring first (ABCs, telemetry, BP) β€’ Bradycardia β†’ atropine β€’ Hypotension β†’ IV fluids β€’ Early β†’ IV calcium (CaCl2 / Ca-gluconate) β€’ Glucagon 3–5 mg IV β€’ Repeat or escalate glucagon β†’ infusion if responsive (often transient) β€’ Persistent shock β†’ HIET (insulin + dextrose) β€’ Monitor glucose + potassium closely β€’ Add vasopressors if shock persists β€’ Wide QRS / ventricular arrhythmia β†’ sodium bicarbonate (membrane-stabilizing toxicity) β€’ Refractory severe lipophilic toxicity β†’ IV lipid emulsion (toxicology-guided) β€’ Pacing β†’ symptomatic high-grade AV block β€’ ECMO β†’ refractory shock (per center) β€’ Severe / unstable β†’ ACLS + ICU / toxicology

Antidote

- Glucagon β†’ non-Ξ² pathway (often transient) - IV calcium β†’ inotropy / conduction support - HIET β†’ metabolic rescue (refractory shock) - IV lipid β†’ lipophilic toxicity (refractory / seizures)

Decontamination

β€’ Recent **oral** ingestion β†’ **activated charcoal** if **protected airway** and within **~1–2 h** (ingestion history + risk/benefit)

Escalation

- Wide QRS / ventricular arrhythmia β†’ sodium bicarbonate (membrane-stabilizing toxicity) - Pacing β†’ symptomatic high-grade AV block - ECMO β†’ refractory shock (per center)

Clinical pearls

Common mistakes, resistance logic, and bedside traps

High-Yield Summary

**ONLY metoprolol succinate ER is guideline-supported for chronic HFrEF**. **DO NOT use metoprolol tartrate for chronic HFrEF**. IV for acute rate control in monitored setting only (hemodynamically stable; no acute decompensated HF; no high-grade AV block).

Clinical pearls

Tartrate and succinate are not interchangeable for chronic HFrEF. Rate-control targets often need higher exposure than BP-only targets. *Ξ²-blockers (class):* **Start low, go slow.** **HF:** only **evidence-based agents** (**metoprolol succinate**, **bisoprolol**, **carvedilol**) for **HFrEF GDMT** β€” not all Ξ²-blockers interchangeable. **Rate control (AF)** vs **BP lowering** β€” titrate to the clinical target.

Beta-blocker safety

  • Formulation check on every refill
  • Taper if stopping long-term

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Metoprolol 10 mg/mL oral suspension

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Pharmacokinetics

**Tartrate** shorter half-life β†’ **multiple daily** dosing; **succinate ER** extended absorption β€” **QD–BID** typical.

Mechanism of action

Competitive **Ξ²1** antagonism β†’ ↓ HR, ↓ myocardial contractility (dose-dependent), ↓ renin.

Common brand names

Saudi Arabia

Lopressor, Beloc, Metocard

Global

Toprol-XL, Lopressor (tartrate), Toprol-XL / Betaloc CR (succinate), (placeholder β€” verify local formulation)

Common trade names are curated examples only β€” formulations and availability vary. Verify the exact product name with your local pharmacy and national regulator before prescribing or dispensing.

Country practice notes

  • Acute **aortic syndromes** and **thyrotoxic storm** are **protocol-driven** β€” Ξ²-blocker choice and targets are **team + guideline** specific.
  • Ξ²-blocker **GDMT for HFrEF** applies only to **evidence-based agents** β€” verify label and cardiology plan before substituting.

References

Saudi Arabia

  • SFDA (Saudi Food & Drug Authority)
  • Saudi National Formulary / MOH (where available)

International

  • WHO Model List of Essential Medicines (verify current edition)
  • US FDA or EU EMA product information (when national SmPC is unavailable)
  • ACC / AHA / HFSA heart failure and hypertension guidance
  • ESC cardiovascular and arrhythmia guidelines where applicable
  • FDA / SFDA product labeling
  • Institutional ICU / toxicology protocols (overdose)
  • ACC / AHA / HFSA heart failure and hypertension guidance
  • ESC cardiovascular and arrhythmia guidelines where applicable
  • FDA / SFDA product labeling
  • Institutional ICU / toxicology protocols (overdose)

Do not miss

  • Teach **not to stop abruptly** after chronic use β€” taper when feasible
  • Titrate to **HR vs BP endpoint** (AF rate control often needs higher exposure than BP alone)
  • Formulation check on every refill
  • Taper if stopping long-term