Procainamide

Adult Dosing

• Continuous infusion rate has fewer adverse effects
  • 20-50mg/min for 25-30min
    • Cont until arrhythmia is suppressed, hypotension, QRS >50% or max dose (17mg/kg)
    • If effective start cont infusion of 1-4mg/min

Contraindications

• Not recommended for V-fib or pulseless V-tach (too long to dose)
• 2nd or 3rd AV block
• Severe glycoside intoxication
• Prolonged QT
• Myasthenia gravis

Indications

• Wide-complex tachycardia of unknown type (in pts w/ preserved LV function)
• Stable V-tach

Mechanism of Action

• Class Ia
  • Binds to fast Na channels in inactive state thereby inhibiting recovery after repolarization
  • Prolongs action potential and reduces speed of impulse conduction
    • Depresses myocardial conduction
  • May act as negative inotrope, cause hypotension (peripheral vasodilation)

Adverse Drug Rxns

• Myocardial depression
• Watch for QRS/QT prolongation, V-tach, Vfib, complete AV block, torsades

Kinetics

• Onset of action = 5-10min

See Also

• Antiarrhythmics