Esmolol !
An ultra-short-acting, β1-selective beta blocker given by IV infusion. Its effect fades within minutes of stopping it.
Updated 2026-11-01
The figure shows the turkey β1 receptor with cyanopindolol, another beta blocker in the same binding site where esmolol acts; no structure with esmolol bound is available.
Mechanism of action
Esmolol blocks β1 receptors in the heart, lowering heart rate, AV conduction and contractility. It carries an ester bond that red blood cell esterases cut quickly, so it can be switched on and off like a dial: useful when a fast, controllable effect is needed, such as tachycardia during surgery or rate control while other treatment is planned.
- Esmolol blocks cardiac β1 receptors
- Heart rate, AV conduction and contractility fall
- Red-cell esterases cut it within minutes, so the effect ends fast
Pharmacokinetics
- Metabolism
- Hydrolysed by esterases in red blood cells, not by plasma cholinesterase
- Half-life
- About 9 minutes
- Onset and duration
- Rapid; without a loading dose, steady state is reached in about 30 minutes
Indications
- Rapid rate control in atrial fibrillation or flutter and other supraventricular tachycardias Atrial fibrillation →
- Tachycardia and hypertension during and after surgery
- Acute blood pressure and heart rate control, for example in aortic dissection Aortic dissection →
Adverse effects
Common
- Hypotension, the most common effect
- Dizziness and sweating
- Nausea
- Pain or inflammation at the infusion site
Contraindications
- Severe sinus bradycardia, sick sinus syndrome or heart block greater than first degree
- Decompensated heart failure or cardiogenic shock
- IV verapamil or other cardiodepressant calcium channel blockers given close by
- Pulmonary hypertension
Key interactions
- IV verapamil or diltiazem
- Severe bradycardia, AV block and cardiac arrest
- Digoxin
- Somewhat higher digoxin levels and added AV slowing
- Succinylcholine
- Longer neuromuscular block
What is monitored
- Continuous ECG and heart rate
- Blood pressure, often every few minutes when starting
- Infusion site
- Breathing in lung disease
Administration and safety
- IV only, with an infusion pump; vials and bags differ in strength, so the label is checked against the order
- Prefer a large vein and avoid small veins or butterfly cannulas; watch the site for extravasation
- Not compatible with sodium bicarbonate in the same line
Nursing care
- Keep the patient on continuous cardiac monitoring with frequent blood pressure checks
- Stop or slow the infusion and call the team if bradycardia or hypotension appears
- Inspect the IV site often for redness, swelling or leakage
- Plan the transition to an oral agent before stopping it, because its effect fades fast
Pregnancy and breastfeeding
Human data are limited; beta blockers given near delivery can cause fetal bradycardia, so it is used only when the benefit justifies it.
Test yourself
Think of the answer, then tap the question to see it.
Why does the effect of esmolol end within minutes of stopping the infusion?
Esterases in red blood cells hydrolyse its ester bond quickly; its half-life is about 9 minutes.
What is the most common adverse effect of esmolol?
Hypotension, which usually resolves when the infusion is lowered or stopped.
Which drug should not be given IV close in time to esmolol?
IV verapamil (or other cardiodepressant calcium channel blockers), because of severe bradycardia and arrest.
Related drugs
Related conditions
← Back to the class: Beta blockers
Educational content on how drugs work; not a prescribing guide and no substitute for a health professional's advice. No doses are given.
Sources: DailyMed - ESMOLOL HYDROCHLORIDE injection, solution (DailyMed (U.S. National Library of Medicine), 2026); ATCDDD - ATC/DDD Index (WHO Collaborating Centre for Drug Statistics Methodology, 2026); Goodman & Gilman's The Pharmacological Basis of Therapeutics, 14th ed., ch. 32 (McGraw Hill, 2023).
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Representative model, for educational purposes only.