Dosing and uses of Procanbid, Pronestyl (procainamide)
Adult dosage forms and strengths
injection solution
- 100 mg/mL
- 500mg/mL
Arrhythmia
Adjust dose to patient's response
IM Administration
- 0.5-1 g IM q4-8hr
IV Administration
- Loading dose: 100-200 mg/dose or 15-18 mg/kg; infuse slowly over 25-30 min not to exceed 50 mg/min; may repeat q5min PRN not to exceed 1 g
- Maintenance: 1-4 mg/min by continuous IV infusion
- Renal impairment:
Renal Impairment
Reduce loading dose to 12 mg/kg
Reduce infusion to one third in moderate renal or cardiac impairment and two thirds in severe renal or cardiac impairment
Hepatic Impairment
Reduce dose by 50%
Pediatric dosage forms and strengths
injection solution
- 100 mg/mL
- 500mg/mL
Arrhythmia
Adjust dose to patient's response
IM Administration
- 20-30 mg/kg/day IM divided q4-6hr; not to exceed 4 g/day
IV Administration
- Loading dose: 3-6 mg/kg IV over 5 minutes, not to exceed 100 mg/dose; may repeat q5-10min PRN not to exceed 15 mg/kg/dose
- Maintenance: 0.02-0.08 mg/kg/min IV infusion; not to exceed 2 g/24 hours
Procanbid, Pronestyl (procainamide) adverse (side) effects
>10%
Increased antinuclear antibodies (50%)
SLE-like syndrome (30%)
1-10%
Hypotension (5%)
Frequency not defined
Arrhythmias
Asystole
Heart block
Wide PR or QRs
Asthenia
Ataxia
Depression
Chills
Psychosis
Abdominal pain
Bitter taste
N/V
Myopathy
Rash
Leukopenia
Warnings
Black box warnings
Positive ANA Titer
- Long-term administration often leads to positive antinuclear antibody (ANA) test result
- Positive result may occur with or without lupus erythematosus-like syndrome symptoms If a positive ANA titer develops, assess benefits vs risks of continuing procainamide
Mortality
- National Heart, Lung, and Blood Institute's Cardiac Arrhythmia Suppression Trial (CAST): Excessive mortality or nonfatal cardiac arrest (7.7%) shown with encainide or flecainide compared with placebo (3%)
- CAST was a long-term, multicenter, randomized, double-blind study in patients with asymptomatic non-life-threatening ventricular arrhythmias who had a myocardial infarction >6 days but <2 yr previously
- Average duration of treatment w/ encainide or flecainide in CAST was 10 months
- Applicability of CAST results to other populations (eg, patients without recent MI) is uncertain
- Reserve use of Class IC antiarrhythmics for life-threatening ventricular arrhythmias: Considering the known proarrhythmic properties of procainamide & lack of evidence of improved survival for any antiarrhythmic drug in patients without life-threatening arrhythmias, procainamide use, as well as other antiarrhythmic agents, should be reserved for patients with life-threatening ventricular arrhythmias
Blood Dyscrasias
- Agranulocytosis, bone marrow depression, leukopenia, neutropenia, aplastic/hypoplastic anemia, thrombocytopenia, & sequelae such as septicemia & septic shock have been reported at a rate of ~0.5%
- Most reported within recommended dosage range and within initial 3 months of treatment
- Fatalities have occurred (~20-25% mortality rate in reported agranulocytosis cases)
- Perform complete blood counts, including white cell, differential, & platelet counts at weekly intervals for the first 3 months & then frequently thereafter
- Check blood count if the patient develops any signs of infection (eg, fever, chills, sore throat, stomatitis), bruising, or bleeding.
- If any of these hematologic disorders is identified, discontinue drug & initiate appropriate treatment
- Blood counts usually return to normal within 1 month of discontinuation
- Caution in patients with preexisting marrow failure or cytopenia
Contraindications
Hypersensitivity to procainamide or other ingredients
Complete heart block, 2°/3° AV block, SLE, torsade de pointes
Cautions
Acute ischemic heart disease, blood dyscrasias, cardiomyopathy, CHF, 1° heart block, liver disease, renal impairment, myasthenia gravis, post MI patients
May produce life-threatening hematologic disorders (leukopenia, agranulocytosis)
Concomitant use of digoxin, other class IA antiarrhythmics
Toxicity if serum level >12 mg/L [51 umol/L]
May exacerbate arhythmias or produce paradoxical ventricular tachycardia in AFib/AFlutter patients
Pregnancy and lactation
Pregnancy category: C
Lactation: crosses into breast milk, discontinue drug or do not nurse
Pregnancy categories
A: Generally acceptable. Controlled studies in pregnant women show no evidence of fetal risk.
B: May be acceptable. Either animal studies show no risk but human studies not available or animal studies showed minor risks and human studies done and showed no risk.
C: Use with caution if benefits outweigh risks. Animal studies show risk and human studies not available or neither animal nor human studies done.
D: Use in LIFE-THREATENING emergencies when no safer drug available. Positive evidence of human fetal risk.
X: Do not use in pregnancy. Risks involved outweigh potential benefits. Safer alternatives exist.
NA: Information not available.
Pharmacology of Procanbid, Pronestyl (procainamide)
Mechanism of action
Class IA (membrane stabilizing) antiarrhythmic agent; inhibits recovery after repolarization resulting in decreasing myocardial excitability and conduction velocity
Direct membrane depressant that decreases conduction velocity, prolongs refractoriness, decreases automaticity and reduces repolarization abnormalities
Absorption
Bioavailability: 75-95%
Peak Plasma Time: 15-60 min (IV/IM)
Distribution
Protein Bound: 15-20%
Vd: 2 L/kg (1.5 L if CHF)
Metabolism
Acetylated in liver to form N-acetylprocainamide (NAPA) (active); ratio of procainamide/NAPA depends upon acetylator phenotype and renal function
Metabolites (active): N-acetylprocainamide (NAPA)
Elimination
Half-Life: 2.5-4.7 hr (parent drug), 6-8 hr (NAPA); increased in renal impairment and geriatrics
Renal Clearance: 150-600 mL/min
Excretion: Urine (30-60%), minimal in bile
Dialyzable: Yes (HD); no (PD)
Administration
IV Incompatibilities:
Additive: bretylium, esmolol, milrinone
Y-site: milrinone
IV Compatibilities
Additive: dobutamine, lidocaine, netilmicin
Y-site: famotidine, heparin, KCl, ranitidine, Vit B/C and Amiodarone
IV Preparation
Solution: 2 g/250 mL D5W or NS (8 mg/mL)
Administration: infusion requires use of an infusion pump; run at 1-6 mg/min (7.5-45 mL/hr)
Slight yellow color of soln will not alter potency; however,
- Do not use when darker than light amber or if soln contains precipitate
