What is the recommended dose of Procainamide (Procanbid, generic name: Procainamide)?

From the Guidelines

Procainamide should be administered with a loading dose of 20 to 50 mg/min until arrhythmia suppressed, hypotension ensues, or QRS prolonged by 50%, or total cumulative dose of 17 mg/kg, as recommended by the 2010 American Heart Association guidelines for cardiopulmonary resuscitation and emergency cardiovascular care 1. The dosing of procainamide is crucial in managing hemodynamically stable monomorphic ventricular tachycardia (VT).

• The loading dose can also be given as 100 mg every 5 minutes until arrhythmia is controlled or other conditions described above are met.
• It is essential to monitor for adverse effects, including bradycardia, hypotension, and torsades de pointes, and to avoid using procainamide in patients with QT prolongation and congestive heart failure (CHF).
• The 2010 guidelines provide the most recent and highest quality evidence for procainamide dosing, superseding earlier recommendations, such as those from the 1996 ACC/AHA guidelines for the management of patients with acute myocardial infarction 1. Key considerations in procainamide therapy include:
• Monitoring ECG parameters, such as QRS and QT intervals, to minimize the risk of proarrhythmia.
• Adjusting the dose in patients with renal impairment to prevent accumulation of the drug and its metabolites.
• Being aware of the potential for drug-induced lupus syndrome with prolonged use. By following the recommended dosing and monitoring guidelines, procainamide can be an effective treatment for ventricular arrhythmias, while minimizing the risk of adverse effects.

From the FDA Drug Label

DOSAGE & ADMINISTRATION Procainamide Hydrochloride Injection is useful for arrhythmias which require immediate suppression and for maintenance of arrhythmia control An initial daily dose of 50 mg per kg body weight may be estimated For treatment of arrhythmias associated with anesthesia or surgical operation, the suggested dose is 100 to 500 mg by intramuscular injection Initial arrhythmia control, under ECG monitoring, may usually be accomplished safely within a half-hour by either of the two methods which follows: a) Direct injection into a vein or into tubing of an established infusion line should be done slowly at a rate not to exceed 50 mg per minute b) Alternatively, a loading infusion containing 20 mg of Procainamide Hydrochloride per mL (1 g diluted to 50 mL with 5% Dextrose Injection, USP) may be administered at a constant rate of 1 mL per minute for 25 to 30 minutes to deliver 500 to 600 mg of PA The maximum advisable dosage to be given either by repeated bolus injections or such loading infusion is 1 g To maintain therapeutic levels, a more dilute intravenous infusion at a concentration of 2 mg/mL is convenient (1000 mg procainamide HCl in 500 mL of 5% Dextrose Injection, USP), and may be administered at 1 to 3 mL/minute.

The procainamide dose is as follows:

• Initial daily dose: 50 mg per kg body weight, divided into fractional doses of one-eighth to one-quarter to be injected intramuscularly every three to six hours.
• Intramuscular injection for arrhythmias associated with anesthesia or surgical operation: 100 to 500 mg.
• Intravenous injection:
  • Direct injection: 50 mg per minute, with doses of 100 mg administered every 5 minutes.
  • Loading infusion: 20 mg of Procainamide Hydrochloride per mL, administered at a constant rate of 1 mL per minute for 25 to 30 minutes to deliver 500 to 600 mg of PA.
• Maximum advisable dosage: 1 g.
• Maintenance infusion: 2 mg/mL, administered at 1 to 3 mL/minute, or 4 mg/mL, administered at 0.5 to 1.5 mL/minute. 2

From the Research

Procainamide Dose

• The effective plasma concentration of procainamide for treating acute ventricular arrhythmias and chronic stable ventricular premature depolarizations (VPDs) is between 4 and 10 micrograms per milliliter 3.
• Higher plasma concentrations of procainamide may be required to treat sustained ventricular arrhythmias 3.
• The dose of procainamide may need to be adjusted when administered concurrently with other antiarrhythmic agents, such as amiodarone, as it can increase serum procainamide levels 4.
• A study comparing intravenous procainamide and amiodarone for the acute treatment of tolerated wide QRS tachycardia found that procainamide was administered at a dose of 10 mg/kg over 20 minutes 5.
• The dosage of procainamide can be affected by the patient's genetic acetylation phenotype, with fast acetylators requiring higher doses to achieve therapeutic plasma concentrations 3.

Factors Affecting Procainamide Dose

• The volume of distribution of procainamide is between 1.5 and 2.5 liters per kilogram, and its plasma protein binding is between 15% and 25% 3.
• Procainamide is metabolized to N-acetylprocainamide (NAPA), which is also antiarrhythmic, and 30-60% of a procainamide dose is excreted as NAPA 3.
• The half-time for elimination of procainamide is between 3 and 7 hours, which can affect the dosing interval 3.
• The dose of procainamide may need to be adjusted in patients with renal or hepatic impairment, as these conditions can affect the drug's elimination 3.