What medication is used to treat tachycardia?

Medication for Acute Tachycardia Management

Adenosine is the first-line medication for acute treatment of supraventricular tachycardia (SVT) after vagal maneuvers fail, with a 91-93% success rate and rapid onset of action within 30 seconds. 1

Initial Approach Based on Hemodynamic Stability

For hemodynamically unstable patients:

• Immediate synchronized cardioversion is required, regardless of medication attempts 1, 2
• Do not delay cardioversion to attempt pharmacological conversion 2

For hemodynamically stable patients with narrow-complex tachycardia:

First-Line: Adenosine

• Dosing: 6 mg rapid IV bolus, followed by 12 mg if no response within 1-2 minutes, can repeat 12 mg once more 1
• Onset: Terminates tachycardia within 30 seconds of administration 3, 4
• Efficacy: 91.4% cumulative success rate with sequential dosing up to 12 mg 3
• Advantages: Extremely short half-life (<10 seconds), allowing rapid repeat dosing if ineffective 5, 4
• Side effects: Common (36% of patients) but transient (<1 minute), including flushing, chest discomfort, and dyspnea 3, 4

Second-Line: Beta-Blockers or Calcium Channel Blockers

When adenosine fails or is contraindicated:

• IV Metoprolol: 2.5-5 mg IV bolus over 2 minutes, can repeat every 10 minutes up to 3 doses 1, 2
• IV Esmolol: 500 mcg/kg bolus over 1 minute, followed by infusion at 50 mcg/kg/min 6
• IV Diltiazem: 0.25 mg/kg (typically 5-10 mg) IV bolus over 2 minutes, followed by infusion at 5-15 mg/h 1
• IV Verapamil: 5-10 mg IV bolus over 2 minutes, can repeat 10 mg after 30 minutes 1

The 2020 ESC Guidelines upgraded the strength of recommendation for beta-blockers in acute management of narrow-QRS tachycardias and AVRT, while downgrading verapamil and diltiazem. 1

Wide-Complex Tachycardia

Assume ventricular tachycardia until proven otherwise:

• Adenosine has increased strength of recommendation for diagnostic and therapeutic use in wide-QRS tachycardias 1
• Procainamide is first-line for stable monomorphic VT without severe heart failure 2
• Amiodarone 5 mg/kg (300 mg) over 1 hour for monomorphic VT with or without heart failure 2, 7

Critical Contraindications and Pitfalls

Never use verapamil or diltiazem in:

• Wide-QRS tachycardia of unknown etiology (risk of hemodynamic collapse if VT) 1
• Pre-excited atrial fibrillation (may precipitate ventricular fibrillation) 1
• Patients with suspected systolic heart failure 1

Adenosine contraindications:

• Known reactive airway disease or bronchospasm 8
• Sinus node dysfunction 8
• Cardiac transplant recipients (may cause prolonged asystole) 8

Specific Tachycardia Types

Inappropriate Sinus Tachycardia:

• Ivabradine alone or with beta-blockers for symptomatic patients 1
• Verapamil/diltiazem are no longer recommended 1

Multifocal Atrial Tachycardia:

• IV Metoprolol or Verapamil for acute treatment 2
• Address underlying pulmonary disease and electrolyte abnormalities 2
• IV magnesium may be helpful even with normal magnesium levels 2

Atrial Flutter:

• Ibutilide or dofetilide for cardioversion 1
• Beta-blockers for rate control 1

Pregnancy Considerations

Avoid all antiarrhythmics in first trimester if possible, but if necessary: 1

• Beta-1 selective blockers (NOT atenolol) or verapamil for women without WPW syndrome
• Flecainide/propafenone for women with WPW but without structural heart disease
• Never use amiodarone, propranolol, procainamide, quinidine, or sotalol 1