====== Esmolol (Brevibloc®) ======

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<WRAP infobox>
^ Esmolol | {{ :cardio:beta_blockers:esmolol_structure.svg?200 |}} |
| Brand Name | Brevibloc® |
| Drug Class | [[cardio:beta_blockers:start|β-Blocker]] (β1-selective) |
| Primary Indication | Acute Rate Control |
| β1 Selectivity | High |
| Intrinsic Sympathomimetic Activity | No |
| Half-Life | ~9 minutes |
| Route | IV only |
| Metabolism | Plasma esterases |
| FDA Approval | 1986 |
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===== Overview =====

Esmolol is a short-acting, β1-selective adrenergic receptor antagonist used for rapid, titratable heart rate control in acute settings.

Its ultra-short half-life (~9 minutes) allows for precise titration and rapid discontinuation if adverse effects occur.

It is commonly used in ICU and perioperative settings.

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===== Mechanism of Action =====

**Receptor Activity**
  * Selective β1-adrenergic receptor antagonist  

**Cardiac Effects**
  * ↓ Heart rate  
  * ↓ Myocardial contractility  
  * ↓ AV nodal conduction  

**Net Effect**
  * Reduced cardiac output  
  * Rate control in tachyarrhythmias  

Minimal β2 activity at therapeutic doses.

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===== Indications =====

  * Acute atrial fibrillation with rapid ventricular response  
  * Supraventricular tachycardia  
  * Intraoperative or postoperative tachycardia  
  * Acute hypertension (short-term control)  
  * Thyroid storm (adjunct therapy)  

Used when rapid onset and rapid offset are desired.

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<WRAP contra>
===== Contraindications =====

Absolute:
  * Severe bradycardia  
  * Second- or third-degree AV block (without pacemaker)  
  * Cardiogenic shock  
  * Decompensated heart failure  

Relative / Caution:
  * Asthma or severe COPD  
  * Hypotension  
  * Peripheral vascular disease  

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===== Dosing =====

IV bolus:
  * 500 mcg/kg over 1 minute  

Continuous infusion:
  * 50–200 mcg/kg/min  

Titrated based on heart rate and blood pressure.

Effects dissipate within 10–20 minutes after discontinuation.

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<WRAP details>
===== Pharmacokinetics =====

Route:
  * Intravenous only  

Metabolism:
  * Rapid hydrolysis by plasma esterases  

Half-life:
  * ~9 minutes  

Elimination:
  * Renal excretion of inactive metabolites  

Short half-life allows rapid reversal of effect.

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<WRAP details>
===== Adverse Effects =====

Common:
  * Hypotension  
  * Bradycardia  

Serious:
  * AV block  
  * Acute heart failure exacerbation  
  * Cardiogenic shock  

Rapid offset reduces prolonged toxicity risk.

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<WRAP details>
===== Drug Interactions =====

Additive AV nodal suppression:
  * [[cardio:ccb:non_dhp|Non-DHP Calcium Channel Blockers]] (verapamil, diltiazem)  
  * Digoxin  

Other antihypertensives:
  * Increased hypotension risk  

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<WRAP monitoring>
===== Monitoring =====

  * Continuous cardiac monitoring  
  * Blood pressure  
  * Heart rate  

Used in monitored settings (ICU, OR, ED).

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<WRAP pearls>
===== Clinical Pearls =====

  * Ultra-short acting β1-selective blocker.  
  * Ideal for unstable or dynamic clinical situations.  
  * Effects disappear quickly after discontinuation.  
  * Metabolized by plasma esterases — not dependent on hepatic metabolism.  
  * Useful in thyroid storm for rapid rate control.  

</WRAP>

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===== Comparison Within Class =====

Compared to [[cardio:beta_blockers:metoprolol|Metoprolol]]:
  * Much shorter half-life  
  * IV only  
  * More titratable  

Compared to [[cardio:beta_blockers:propranolol|Propranolol]]:
  * β1-selective  
  * Less bronchospasm risk  

Compared to [[cardio:beta_blockers:sotalol|Sotalol]]:
  * No potassium channel blockade  
  * Not used for rhythm control  

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===== Related =====

  * [[cardio:beta_blockers:start|Beta-Blockers]]
  * [[cardio:arrhythmias:start|Arrhythmias]]
  * [[cardio:beta_blockers:metoprolol|Metoprolol]]
  * [[cardio:beta_blockers:propranolol|Propranolol]]