Clinical beta

FMBM is currently in clinical beta. Content is for professional review/testing and must not replace local protocols, senior clinical judgment, or official prescribing references.

Drug Monograph

Labetalol

Labetalol

Combined **Ξ±1 + non-selective Ξ²** blocker

AdultBBHTNPregnancyIV

Indication

Chronic HTN β€’ Pregnancy HTN (OB protocol) β€’ Acute HTN in ED/ICU/L&D (IV)

At a glance

INDICATIONS (CORE USE)

**Hypertension** β€” **first-line oral/IV** in many **pregnancy HTN / pre-eclampsia** pathways. **IV** bolus/infusion for **acute severe HTN** in monitored setting.

ADULT DOSE (STANDARD)

**PO:** **start low** (e.g. **100 mg BID**) β†’ titrate β€” **orthostasis** **IV:** **bolus** or **infusion** per protocol β€” **frequent BP** checks

MAX DOSE

**IV** cumulative limits per protocol; **oral** titrate to BP β€” avoid hypotension

Route

PO; IV

PEDIATRIC DOSE

Rare pediatric HTN β€” specialist

Do not miss

Must-not-miss safety points

Major warning

- Hypotension β€” especially IV push - Bronchospasm (Ξ²2 blockade component) - Hepatic injury β€” rare idiosyncratic β€” LFTs if unwell

Indications

USE IF: HTN especially **pregnancy**, acute severe HTN with monitoring. AVOID IF: asthma with active bronchospasm, severe bradycardia, or high-grade AV block (without pacing).

Primary

  • Hypertension (including **pregnancy-associated hypertension** β€” OB protocol)

Secondary

  • Acute severe hypertension in **monitored** setting (IV titration)

Dosing

STANDARD (ADULT PO)

**Oral BID**; **IV** per acute HTN protocol

ADULT DOSE

**Oral:** **100 mg BID** start β†’ titrate by **BP**. **IV:** **10–20 mg** bolus (may repeat) or **infusion** β€” **L&D/ED** protocol; watch **fetal** tracing if pregnant.

PEDIATRIC DOSE

Specialist

MAX DOSE

**Oral** often **200–400 mg/day** in divided doses β€” individualized; **IV** max per protocol

Practical Note

**Never** give large rapid IV without **BP monitor** and **resuscitation** readiness.

Warnings

Clinical warnings

  • Ξ±1 + Ξ² blockade β†’ orthostatic hypotension (early). Reactive airway β†’ caution (Ξ²2 still relevant). HOLD if HR <50–55, SBP <90–100, symptomatic bradycardia, high-grade AV block, or acute decompensated HF with shock/hypoperfusion.
  • Rapid IV push without monitoring can cause severe hypotension / collapse
  • Masks hypoglycemia

Adverse effects

  • Orthostatic hypotension
  • fatigue
  • bronchospasm
  • scalp tingling (transient IV)

Contraindications

  • Severe bradycardia
  • High-grade AV block (without pacing)
  • Asthma with Ξ²-blocker contraindication
  • Severe hepatic failure (label)

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
  • Other vasodilators / antihypertensives (including nitroglycerine): additive hypotension

Special populations

Pediatrics

Rare pediatric HTN β€” specialist

Pregnancy

**Pregnancy:** commonly **preferred Ξ²-blocker class** for HTN vs many alternatives β€” still **OB protocol**. **

Lactation

** compatible at usual doses per most references β€” pediatric if concern.

Renal impairment

Adjust cautiously if renal impairment β€” hypotension risk dominates.

Hepatic impairment

**Hepatotoxicity** rare β€” stop if **ALT** rises + symptoms.

Elderly

Orthostasis β€” measure standing BP.

Administration

**IV** slow per protocol; **oral** with food may help GI.

Monitoring

  • Monitor: - Symptoms β†’ dizziness, syncope, fatigue - β€’ Standing BP early β€” Ξ±-blockade can worsen orthostasis (first days of titration) - **Fetal status** if pregnant during IV therapy - **BP q few min** during IV titration
  • 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

**Pregnancy HTN** β€” know **local OB** first-line; **labetalol** is common.

Clinical pearls

**Not** the same as **pure Ξ²-blocker** β€” **orthostasis** earlier. *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

  • OB co-management in pregnancy
  • IV monitoring

Pharmacokinetics

Hepatic clearance β€” active metabolites; IV onset rapid.

Mechanism of action

**Ξ±1** vasodilation + **Ξ²** blockade β†’ ↓ BP with reflex mitigation vs pure vasodilator.

Common brand names

Saudi Arabia

Trandate, Labetalol

Global

Normodyne, (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)
  • OB co-management in pregnancy
  • IV monitoring