What is the recommended dose of esmolol (beta-blocker) for controlling heart rate in conditions like supraventricular tachycardia or perioperative tachycardia and hypertension?

Esmolol Dosing for Heart Rate Control

For supraventricular tachycardia or perioperative tachycardia/hypertension, administer esmolol as a 500 mcg/kg loading dose over 1 minute, followed by a continuous infusion starting at 50 mcg/kg/min, titrating upward in 50 mcg/kg/min increments every 4-5 minutes as needed to a maximum of 200 mcg/kg/min. 1, 2

Loading Dose Protocol

• Standard loading dose: 500 mcg/kg infused over 1 minute for both supraventricular tachycardia and perioperative tachycardia 1, 2
• Alternative loading for immediate perioperative control: 1000 mcg/kg (1 mg/kg) over 30 seconds when more rapid control is required 1, 2
• Repeat loading doses may be administered if initial response is inadequate, with the bolus repeated before each infusion rate increase 1, 2

Maintenance Infusion Dosing

For Supraventricular Tachycardia (Including Atrial Fibrillation/Flutter)

• Initial infusion: 50 mcg/kg/min immediately following the loading dose 1, 2
• Titration schedule: Increase by 50 mcg/kg/min increments every 4 minutes based on heart rate and blood pressure response 1, 2
• Maximum dose: 200 mcg/kg/min 1, 2
• Onset of action: Full therapeutic effect within 5 minutes of loading dose 1, 3

For Perioperative Tachycardia and Hypertension

• Gradual control approach: 50 mcg/kg/min initial infusion after 500 mcg/kg loading dose 1, 2
• Immediate control approach: 150 mcg/kg/min initial infusion after 1 mg/kg loading dose 1, 2
• Maximum for tachycardia: 200 mcg/kg/min 1, 2
• Maximum for hypertension: 300 mcg/kg/min 1, 2
• Titration interval: Adjust dose at minimum 4-minute intervals using ventricular rate or blood pressure as endpoints 1, 2

Clinical Efficacy Data

• Response rates: 66-79% of patients with supraventricular tachyarrhythmias achieve therapeutic response, comparable to propranolol 4, 5
• Typical effective dose: Most patients (all in one study) achieved 15% heart rate reduction at maintenance doses ≤150 mcg/kg/min 6
• Time to effect: 5-18 minutes from initiation to achieve 15% heart rate reduction 6
• Recovery time: Beta-blockade reverses within 10-30 minutes after discontinuation, compared to 4.5 hours with propranolol 4, 5, 3

Critical Contraindications

Absolute contraindications that mandate avoiding esmolol entirely: 2

• Severe sinus bradycardia
• Heart block greater than first degree
• Sick sinus syndrome
• Decompensated heart failure or cardiogenic shock
• Concurrent IV calcium-channel antagonists (e.g., verapamil) administered in close proximity
• Pulmonary hypertension
• Known hypersensitivity to esmolol

Monitoring Requirements

• Continuous ECG monitoring throughout infusion 1, 2
• Blood pressure checks at minimum every 4 minutes during titration 1, 2
• Watch for hypotension: Most common adverse effect, occurring in up to 44% of patients, but typically resolves during or shortly after infusion 4, 5
• Monitor for bradycardia: Dose-dependent effect requiring infusion rate reduction 1

Special Clinical Contexts

High Adrenergic States

• Particularly effective in perioperative settings and postoperative supraventricular tachycardia where sympathetic tone is elevated 1, 6
• Blocks norepinephrine effects associated with surgical stress (endotracheal intubation, sternotomy, aortic dissection) 4, 7

Patients on Digoxin

• Esmolol can be safely added when digoxin alone provides inadequate rate control 6
• In one study, 11 patients receiving digoxin (average 0.6 mg, serum level 1.19 mg/100 mL) achieved adequate control only after esmolol addition 6
• Caution: Risk of additive bradycardia when combined with digitalis glycosides 2

Diabetes and Reactive Airway Disease

• Diabetes: Esmolol increases hypoglycemic agent effects and masks hypoglycemic tachycardia 2
• Asthma/COPD: Higher doses (>200 mcg/kg/min) may block beta-2 receptors and worsen bronchospasm 1, 2
• Relative contraindication in reactive airways disease, though better tolerated than non-selective beta-blockers 1, 2

Practical Dosing Algorithm

1. Verify no absolute contraindications (heart block, decompensated HF, severe bradycardia, concurrent IV calcium-channel blockers) 2
2. Administer loading dose: 500 mcg/kg over 1 minute (or 1000 mcg/kg over 30 seconds if immediate control needed perioperatively) 1, 2
3. Start maintenance infusion: 50 mcg/kg/min (or 150 mcg/kg/min for immediate perioperative control) 1, 2
4. Assess response at 4 minutes: Check heart rate and blood pressure 1, 2
5. If inadequate response: Repeat loading dose and increase infusion by 50 mcg/kg/min 1, 2
6. Continue titration: Every 4 minutes until target heart rate achieved or maximum dose reached (200 mcg/kg/min for SVT/perioperative tachycardia; 300 mcg/kg/min for perioperative hypertension) 1, 2
7. Reduce or discontinue if hypotension, bradycardia, or heart failure develops 1, 2

Duration of Therapy

• FDA-approved for short-term use only 2
• Maximum studied duration: 24 hours of continuous infusion 5, 6
• Pharmacokinetics: Elimination half-life approximately 9 minutes, allowing rapid titration and quick offset 2, 4, 3