Drug information of Procainamide


Drug group:

Procainamide hydrochloride, a Group 1A cardiac antiarrhythmic drug, Procainamide is a derivative of procaine with less CNS action

Mechanism of effect

Procainamide is sodium channel blocker. Procainamide stabilizes the neuronal membrane by inhibiting the ionic fluxes required for the initiation and conduction of impulses thereby effecting local anesthetic action.


Procainamide is an agent indicated for production of local or regional anesthesia and in the treatment of ventricular tachycardia occurring during cardiac manipulation, such as surgery or catheterization, or which may occur during acute myocardial infarction, digitalis toxicity, or other cardiac diseases.

The mode of action of the antiarrhythmic effect of Procainamide appears to be similar to that of procaine and quinidine. Ventricular excitability is depressed and the stimulation threshold of the ventricle is increased during diastole. The sinoatrial node is, however, unaffected.



Bioavailability: 75-95%

Peak Plasma Time: 15-60 min (IV/IM)


Protein Bound: 15-20%

Vd: 2 L/kg (1.5 L if CHF)


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)


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)

Drug indications

ventricular arrhythmias


  • Dosage Forms & Strengths

injection solution

100 mg/mL



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:

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%


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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


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


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

Points of recommendation

  • Tell your Doctor:
  • If you have an allergy to procainamide or any other part of procainamide.
  • If you are allergic to any drugs like this one, any other drugs, foods, or other substances. Tell your doctor about the allergy and what signs you had, like rash; hives; itching; shortness of breath; wheezing; cough; swelling of face, lips, tongue, or throat; or any other signs.
  • If you have heart block
  • If you have lupus.
  • If you have ever had a certain type of abnormal heartbeat (torsades de pointes).
  • If you are breast-feeding or plan to breast-feed.
  • Tell your doctor and pharmacist about all of your drugs (prescription or OTC, natural products, vitamins) and health problems. You must check to make sure that it is safe for you to take procainamide with all of your drugs and health problems. Do not start, stop, or change the dose of any drug without checking with your doctor.
  • Tell all of your health care providers that you take this medicine. This includes your doctors, nurses, pharmacists, and dentists.
  • Have blood work checked as you have been told by the doctor. Talk with the doctor.
  • Have your blood pressure checked often. Talk with your doctor.
  • You will need an ECG before starting procainamide and during treatment. Talk with your doctor.
  • This medicine may affect certain lab tests. Tell all of your health care providers and lab workers that you take this medicine.
  • You may bleed more easily. Be careful and avoid injury. Use a soft toothbrush and an electric razor.
  • You may have more chance of getting an infection. Wash hands often. Stay away from people with infections, colds, or flu.
  • If you are allergic to sulfites, talk with your doctor. Some products have sulfites.
  • Talk with your doctor before you drink alcohol.
  • Myasthenia gravis that has gotten worse has happened during care with procainamide. Talk with the doctor.
  • If you are 65 or older, use this medicine with care. You could have more side effects.
  • Tell your doctor if you are pregnant or plan on getting pregnant. You will need to talk about the benefits and risks of using procainamide while you are pregnant.

Pregnancy level


Related drugs

Disopyramide , Quinidine

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