Procainamide (Class 1A)

Pharmacology of Procainamide

• Decreases automaticity
• Increases refractory period
• Slows AV conduction (No need for a cardiac glycoside adjunctly)

Procainamide Use (available for intravenous use unlike quinidine)

• Atrial tachycardia
• Atrial fibrillation
• Ventricular arrhythmia (intravenous use when lidocaine fails or is contraindicated)

Adverse reaction

• Lupus-Like: With high doses a lupus-like syndrome can happen. Hydralazine used for hypotension had the same symptom and just like hydralazine, it was dose related and reversible if you stopped the drug.
• Arrhythmogenic: Each one of these cardiac antiarrhythmic drugs are used to treat an arrhythmia and they can cause other cardiac arrhythmias. There have been many of these drugs pulled from the market because they potentially caused fatal arrhythmia.