What is the use of Procainamide (Procanbid, Pronestyl)?

From the Guidelines

Procainamide is a Class IA antiarrhythmic medication that should be used with caution due to its potential to cause proarrhythmia, including torsades de pointes, and is typically reserved for life-threatening ventricular arrhythmias or when other treatments have failed 1.

Key Considerations

• Procainamide works by blocking sodium channels in cardiac tissue, which slows conduction and increases the refractory period, helping to terminate and prevent recurrence of abnormal heart rhythms.
• The typical dosing for acute arrhythmias is 20-50 mg/min IV infusion up to 17 mg/kg total, followed by maintenance of 1-4 mg/min, as recommended by the 2010 American Heart Association guidelines for cardiopulmonary resuscitation and emergency cardiovascular care 1.
• Important considerations include monitoring for QT prolongation, hypotension, and the development of drug-induced lupus with long-term use.
• Procainamide should be used cautiously in patients with renal impairment, as dose adjustments are necessary, and blood levels should be monitored during therapy, with therapeutic ranges between 4-10 μg/mL.

Potential Side Effects and Contraindications

• Procainamide may cause proarrhythmia, including torsades de pointes, and is contraindicated in patients with complete heart block, torsades de pointes, or systemic lupus erythematosus.
• Other potential side effects include bradycardia, hypotension, and CNS toxicity.

Clinical Use

• Procainamide is indicated for life-threatening ventricular arrhythmias, but is usually not the drug of first choice, and may be used when therapy is required and lidocaine has failed or is contraindicated 1.
• It may also be used for wide complex tachycardias of uncertain mechanism, although it is usually not the drug of first choice in this setting.

From the FDA Drug Label

Procainamide hydrochloride injection is indicated for the treatment of documented ventricular arrhythmias, such as sustained ventricular tachycardia, that, in the judgement of the physician, are life-threatening. The primary use of procainamide is for the treatment of life-threatening ventricular arrhythmias, such as sustained ventricular tachycardia.

• The drug is not recommended for use with lesser arrhythmias due to its proarrhythmic effects.
• Initiation of treatment should be carried out in a hospital setting.
• The use of procainamide should be reserved for patients where the benefits outweigh the risks, due to the potential for serious hematological disorders 2.

From the Research

Uses of Procainamide

• Procainamide is used to prevent recurrent ventricular tachycardia or symptomatic nonsustained ventricular tachycardia, either alone or in combination with class I agents 3.
• It is also used for short-term treatment of ventricular tachycardia and various supraventricular tachycardias, including atrial flutter and atrial fibrillation 3, 4.
• Procainamide is the drug of choice for patients requiring both immediate and intermediate periods of arrhythmia control, and is often used for initial testing with programmed electrical stimulation 4.

Efficacy and Safety

• A study found that intravenous procainamide is safe and effective in treating acute atrial fibrillation or flutter in the emergency department, with a conversion rate of 52.2% for atrial fibrillation and 28.0% for atrial flutter 5.
• Another study compared intravenous procainamide with intravenous amiodarone for the acute treatment of tolerated wide QRS tachycardia, and found that procainamide was associated with fewer major cardiac adverse events and a higher proportion of tachycardia termination within 40 minutes 6.
• Procainamide has also been shown to reduce arrhythmias in the early postoperative period after coronary artery bypass surgery, particularly in patients who achieve therapeutic serum levels 7.

Administration and Monitoring

• Procainamide levels can be useful in initial dose titrations, but QRS and QT interval measurements are also important to prevent drug toxicity 3.
• Patients starting antiarrhythmic therapy with procainamide should be admitted to the hospital for monitoring to ensure that their QT interval is not excessively prolonged 3.
• The standard clinical protocol for intravenous procainamide involves infusion of 1 g over 60 minutes, followed by electrical cardioversion if necessary 5.