Usual Adult Dose for Arrhythmias

IV:
Loading dose: 15 to 18 mg/kg administered as slow infusion over 25 to 30 minutes or 100 mg/dose at a rate not to exceed 50 mg/minute repeated every 5 minutes as needed to a total dose of 1 gram.
Maintenance dose: 1 to 4 mg/minute by continuous infusion. Maintenance infusions should be reduced by one-third in patients with moderate renal or cardiac impairment and by two-thirds in patients with severe renal or cardiac impairment.

ACLS guidelines: Loading dose: Infuse 20 mg/minute (up to 50 mg/minute for more urgent situations) until arrhythmia is controlled, hypotension occurs, QRS complex widens by 50% of its original width, or total of 17 mg/kg is given. Note: Not recommended for use in ongoing ventricular fibrillation (VF) or pulseless ventricular tachycardia (VT) due to prolonged administration time and uncertain efficacy. Follow with maintenance dose as continuous infusion.

IM:
50 mg/kg divided into fractional amounts of 1/8 to 1/4 and injected every 3 to 6 hours or 0.5 to 1 gram every 4 to 8 hours.

Oral: ORAL procainamide is not available in the US but is available in Canada.
40 to 50 kg:
Immediate-release: 250 mg orally every 3 hours.
Sustained-release: 500 mg every 6 hours.
Twice daily formulation: 1000 mg every 12 hours.

60 to 70 kg:
Immediate-release: 375 mg every 3 hours.
Sustained-release: 750 mg every 6 hours.
Twice daily formulation: 1500 mg every 12 hours.

80 to 90 kg:
Immediate-release: 500 mg every 3 hours.
Sustained-release: 1000 mg every 6 hours.
Twice daily formulation: 2000 mg every 12 hours.

100 kg or more (Immediate-release) 625 mg every 3 hours.
Sustained-release: 1250 mg every 6 hours.
Twice daily formulation: 2500 mg every 12 hours.

Usual Pediatric Dose for Arrhythmias

less than 1 month:
Loading dose: 7 to 10 mg/kg IV infused over 60 minutes followed by a continuous IV infusion of 20 to 80 mcg/kg/minute; a retrospective study of 20 neonates (GA: 25 weeks or older) reported a mean loading dose of 9.6 ± 1.5 mg/kg and a mean continuous infusion rate of 37.56 ± 13.52 mcg/kg/minute. Note: Procainamide serum concentrations were supratherapeutic in five neonates studied; four of the five were less than 36 weeks GA and all five had Clcr less than 30 mL/minute/1.73 m2; these results indicate that doses may need to be decreased in preterm neonates and in those with renal impairment.

1 year or older:
Oral: (ORAL procainamide is not available in the US but is available in Canada.)
15 to 50 mg/kg/day divided every 3 to 6 hours. Maximum 4 g/day.

IV:
loading dose: 3 to 6 mg/kg over 5 minutes (not to exceed 100 mg per dose), may repeat every 5 to 10 minutes to maximum total loading dose of 15 mg/kg; do not exceed 500 mg in 30 minutes.
maintenance dose: continuous IV infusion: 20 to 80 mcg/kg/minute; maximum dose: 2 g/day.

IM:
20 to 30 mg/kg/day divided every 4 to 6 hours. Maximum 4 g/day.

Stable wide complex tachycardia of unknown origin (atrial or ventricular) or SVT (PALS, 2010): Note: Avoid or use extreme caution when administering procainamide with other drugs that prolong QT interval (e.g., amiodarone); consider consulting with expert.
Loading dose: 15 mg/kg infused intravenously over 30 to 60 minutes; monitor ECG and blood pressure; stop the infusion if hypotension occurs or QRS complex widens by more than 50% of baseline

Renal Dose Adjustments

Oral:
CrCl less than 10 mL/min: A dosing interval of every 8 to 24 hours is recommended.
CrCl 10 to 50 mL/min: A dosing interval of every 6 to 12 hours is recommended.

IV:
Reduce loading dose to 12 mg/kg in severe renal impairment.
Maintenance infusions should be reduced by one-third in patients with moderate renal impairment and by two-thirds in patients with severe renal impairment.

Liver Dose Adjustments

A 50% reduction in the dose is recommended.

Dose Adjustments

Patients with congestive heart failure should receive 2/3 of the loading dose.
Patients that have a slow acetylator phenotype should receive 2/3 of the maintenance dose.
Patients that have a fast acetylator phenotype should receive 1/3 higher maintenance dose.

Precautions

US BOXED WARNINGS:

• ANTI-NUCLEAR ANTIBODY (ANA) TEST: Prolonged administration of this drug often leads to the development of a positive ANA test, with or without symptoms of a lupus erythematosus-like syndrome. If a positive ANA titer develops, the benefit versus risks of continued treatment with this drug should be assessed.
• MORTALITY: In the National Heart, Lung and Blood Institute's Cardiac Arrhythmia Suppression Trial (CAST), a long-term, multicentered, randomized, double-blind study in patients with asymptomatic non-life-threatening ventricular arrhythmias who had a myocardial infarction more than 6 days but less than 2 years previously, an excessive mortality or non-fatal cardiac arrest rate (7.7%) was seen in patients treated with encainide or flecainide compared with that seen in patients assigned to matched placebo-treated group (3%). The average duration of treatment with encainide or flecainide in this study was 10 months. The applicability of the CAST results to other populations (e.g., those without recent myocardial infarctions) is uncertain. Considering the known proarrhythmic properties of this drug and the lack of evidence of improved survival for any antiarrhythmic drug in patients without life-threatening arrhythmias, the use of this drug as well as other antiarrhythmic agents should be reserved for patients with life-threatening ventricular arrhythmias.
• BLOOD DYSCRASIAS: Agranulocytosis, bone marrow depression, neutropenia, hypoplastic anemia, and thrombocytopenia in patients receiving this drug have been reported at a rate of approximately 0.5%. Most of these patients received this drug within the recommended dosage range. Fatalities have occurred (with approximately 20% to 25% mortality in reported cases of agranulocytosis). Since most of these events have been noted during the first 12 weeks of therapy, it is recommended that CBCs including white cell, differential, and platelet counts be performed at weekly intervals for the first 3 months of therapy, and periodically thereafter. CBCs should be performed promptly if the patient develops any signs of infection (such as fever, chills, sore throat, or stomatitis), bruising, or bleeding. If any of these hematologic disorders are identified, treatment with this drug should be discontinued. Blood counts usually return to normal within 1 month of discontinuation. Caution should be used in patients with pre-existing marrow failure or cytopenia of any type.

• This drug should be considered a narrow therapeutic index (NTI) drug as small differences in dose or blood concentrations may lead to serious therapeutic failures or adverse drug reactions.

• Generic substitution should be done cautiously, if at all, as current bioequivalence standards are generally insufficient for NTI drugs.
• Additional and/or more frequent monitoring should be done to ensure receipt of an effective dose while avoiding unnecessary toxicities.

Dialysis

Moderately hemodialyzable (20% to 50%):
Monitor procainamide/N-acetylprocainamide (NAPA) levels; a 200 mg supplemental dose post-hemodialysis may be necessary.
NAPA: Not dialyzable (0% to 5%)
Procainamide/NAPA: Not peritoneal dialyzable (0% to 5%)
Procainamide/NAPA: Replace by blood level during continuous arteriovenous or venovenous hemofiltration.