What medication should be given for rate control in a patient with tachycardia?

Rate Control Medication for Tachycardia

Beta-blockers are the first-line agents for rate control in tachycardia, with metoprolol being the most commonly used and effective option for achieving target heart rates both at rest and during exercise. 1

Primary Recommendation: Beta-Blockers

Beta-blockers should be initiated as first-line therapy for rate control, achieving heart rate endpoints in 70% of patients compared to 54% with calcium channel blockers. 2

Specific Beta-Blocker Options and Dosing:

For acute/IV administration in hemodynamically stable patients: 1

• Metoprolol tartrate: 2.5-5 mg IV bolus over 2 minutes; up to 3 doses 1
• Esmolol: 500 mcg/kg IV bolus over 1 minute, followed by 50-300 mcg/kg/min infusion (useful for its short 2-9 minute half-life) 1
• Propranolol: 1 mg IV over 1 minute, up to 3 doses at 2-minute intervals 1

For chronic oral maintenance: 1, 2

• Metoprolol tartrate: 25-100 mg twice daily 1
• Metoprolol succinate (extended-release): 50-400 mg once daily 1, 2
• Atenolol: 25-100 mg once daily 1
• Carvedilol: 3.125-25 mg twice daily 1

Second-Line: Non-Dihydropyridine Calcium Channel Blockers

If beta-blockers are contraindicated or ineffective, use diltiazem or verapamil, particularly in patients with chronic obstructive pulmonary disease where beta-blockers should be avoided. 1

Dosing for Calcium Channel Blockers:

Diltiazem: 1, 2

• IV: 0.25 mg/kg bolus over 2 minutes, then 5-15 mg/hour infusion
• Oral: 120-360 mg once daily (extended-release)

Verapamil: 1

• IV: 0.075-0.15 mg/kg bolus over 2 minutes; may repeat with 10 mg after 30 minutes
• Oral: 180-480 mg once daily (extended-release)

Note: A recent ED study demonstrated diltiazem achieved target heart rate <100 bpm in 95.8% of patients by 30 minutes versus only 46.4% with metoprolol, suggesting diltiazem may be more effective for rapid rate control in acute settings. 3

Alternative Agents for Specific Situations

Digoxin:

Use primarily in patients with heart failure or left ventricular dysfunction, though it is less effective during exercise. 1, 2

• IV: 0.25 mg with repeat dosing to maximum 1.5 mg over 24 hours 1
• Oral maintenance: 0.125-0.25 mg once daily 1

Amiodarone:

Reserve for critically ill patients or when conventional measures fail, as it has slower onset and multiple side effects. 1, 2

• IV: 150 mg over 10 minutes, then 1 mg/min for 6 hours, then 0.5 mg/min 1, 2
• Oral maintenance: 100-200 mg once daily 1

Critical Contraindications and Safety Considerations

Avoid beta-blockers in: 1, 2

• Asthma or obstructive airway disease
• Decompensated heart failure
• Pre-excited atrial fibrillation/flutter (Wolff-Parkinson-White syndrome)

Avoid calcium channel blockers in: 1, 2

• Decompensated heart failure (may cause further hemodynamic compromise)
• Pre-excited atrial fibrillation/flutter

Never use digoxin, calcium channel blockers, or IV amiodarone in pre-excitation syndromes, as they may accelerate ventricular response and precipitate ventricular fibrillation. 1, 2

Dronedarone should never be used for rate control in permanent atrial fibrillation due to increased risk of stroke, MI, and cardiovascular death. 1

Target Heart Rate Goals

Aim for resting heart rate <80 bpm for symptomatic management, though lenient control (<110 bpm) may be reasonable in asymptomatic patients with preserved left ventricular function. 1

Assess heart rate control during exertion and adjust therapy accordingly, as many agents (particularly digoxin) lose effectiveness during exercise. 1

When Immediate Intervention is Required

In hemodynamically unstable patients (hypotension, ongoing ischemia, decompensated heart failure), electrical cardioversion is preferred over pharmacological rate control. 1