pharmacopeia
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Boxed warning

The prolonged administration of procainamide often leads to the development of a positive anti-nuclear antibody (ANA) test, with or without symptoms of a lupus erythematosus-like syndrome. If a positive ANA titer develops, the benefit versus risks of continued procainamide therapy should be assessed.

Mechanism of action

Sourced from openFDA

Mechanism-of-action class: Unknown Cellular or Molecular Interaction.

Indications

Sourced from openFDA
  • 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. Because of the proarrhythmic effects of procainamide, its use with lesser arrhythmias is generally not recommended.

Contraindications

Sourced from openFDA
  • Complete Heart Block: Procainamide should not be administered to patients with complete heart block because of its effects in suppressing nodal or ventricular pacemakers and the hazard of asystole. It may be difficult to recognize complete heart block in patients with ventricular tachycardia, but if significant slowing of ventricular rate occurs during PA treatment without evidence of A-V conduction appearing, PA should be stopped.contraindicated

Dosage & administration

Sourced from openFDA

Procainamide Hydrochloride Injection is useful for arrhythmias which require immediate suppression and for maintenance of arrhythmia control. Intravenous therapy allows most rapid control of serious arrhythmias, including those following myocardial infarction; it should be carried out in circumstances where close observation and monitoring of the patient are possible, such as in hospital or emergency facilities. Intramuscular administration is less apt to produce temporary high plasma levels but therapeutic plasma levels are not obtained as rapidly as with intravenous administration. Oral procainamide dosage forms are preferable for less urgent arrhythmias as well as for long-term maintenance after initial parenteral PA therapy. Intramuscular administration may be used as an alternative to the oral route for patients with less threatening arrhythmias but who are nauseated or vomiting, who are ordered to receive nothing by mouth preoperatively, or who may have malabsorptive problems. An initial daily dose of 50 mg per kg body weight may be estimated. This amount should be divided into fractional doses of one-eighth to one-quarter to be injected intramuscularly every three to six hours until oral therapy is possible. If more than three injections are given, the physician may wish to assess patient factors such as age and renal function (see below), clinical response and, if available, blood levels of PA and NAPA in adjusting further doses for that individual.

Warnings & precautions

Sourced from openFDA

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 six days but less than two 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 (3.0%). The average duration of treatment with encainide or flecainide in this study was ten 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 procainamide and the lack of evidence of improved survival for any antiarrhythmic drug in patients without life-threatening arrhythmias, the use of procainamide 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 procainamide hydrochloride have been reported at a rate of approximately 0.5%. Most of these patients received procainamide within the recommended dosage range. Fatalities have occurred (with approximately 20–25 percent mortality in reported cases of agranulocytosis).

Adverse reactions

Sourced from openFDA

Cardiovascular System : Hypotension and serious disturbances of cardiorhythm such as ventricular asystole or fibrillation are more common with intravenous administration of PA than with intramuscular administration. Because PA is a peripheral vasodilator in concentrations higher than the usual therapeutic range, transient high plasma levels which may occur especially during intravenous administration may produce temporary but at times severe lowering of blood pressure (see OVERDOSAGE and PRECAUTIONS ). Multisystem: A lupus erythematosus-like syndrome of arthralgia, pleural or abdominal pain, and sometimes arthritis, pleural effusion, pericarditis, fever, chills, myalgia, and possibly related hematologic or skin lesions (see below) is fairly common after prolonged PA administration, perhaps more often in patients who are slow acetylators (See Boxed Warning and PRECAUTIONS ). While some series have reported less than 1 in 500, others have reported the syndrome in up to 30 percent of patients on long term oral PA therapy. If discontinuation of PA does not reverse the lupoid symptoms, corticosteroid treatment may be effective. Hematologic: Neutropenia, thrombocytopenia, or hemolytic anemia may rarely be encountered. Agranulocytosis has occurred after repeated use of PA, and deaths have been reported. (See Boxed Warning , WARNINGS section.) Skin: Angioneurotic edema, urticaria, pruritus, flushing, and maculopapular rash have also occurred.

Overdosage

Sourced from openFDA

Progressive widening of the QRS complex, prolonged Q-T and P-R intervals, lowering of the R and T waves, as well as increasing A-V block, may be seen with doses which are excessive for a given patient. Increased ventricular extrasystoles, or even ventricular tachycardia or fibrillation may occur. After intravenous administration but seldom after oral therapy, transient high plasma levels of PA may induce hypotension, affecting systolic more than diastolic pressures, especially in hypertensive patients. Such high levels may also produce central nervous depression, tremor, and even respiratory depression. Plasma levels above 10 mcg/mL are increasingly associated with toxic findings, which are seen occasionally in the 10 to 12 mcg/mL range, more often in the 12 to 15 mcg/mL range, and commonly in patients with plasma levels greater than 15 mcg/mL. Treatment of overdosage or toxic manifestations includes general supportive measures, close observation, monitoring of vital signs and possibly intravenous pressor agents and mechanical cardiorespiratory support. If available, PA and NAPA plasma levels may be helpful in assessing the potential degree of toxicity and response to therapy.

Approval history

Sourced from openFDA
  • Jul 31, 1984ANDAANDA088636Intl Medication
  • Feb 12, 1986ANDAANDA089069Hospira
  • Oct 13, 2017ANDAANDA206332Nexus
  • Jul 22, 2024ANDAANDA218135Gland
  • Feb 4, 2025ANDAANDA218674Caplin

FAERS reports

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Reference statistics only. FAERS reports are voluntarily submitted and are not incidence rates, safety signals, or causal evidence. Counts reflect reporting volume — how often a reaction was reported, not how often it occurs. For decision-grade use, consult openFDA and the FAERS Public Dashboard directly.
241 total reports matchedLatest report Share = reports listing the reaction ÷ total matched reports. Rows can sum to >100% because a single report often lists multiple reactions.
  1. 1Drug Ineffective9439%
  2. 2Off Label Use3213%
  3. 3Atrial Fibrillation218.7%
  4. 4Maternal Exposure During Pregnancy197.9%
  5. 5Systemic Lupus Erythematosus197.9%
  6. 6Ascites187.5%
  7. 7Drug Ineffective For Unapproved Indication187.5%
  8. 8Electrocardiogram Qt Prolonged187.5%
  9. 9Fatigue187.5%
  10. 10Respiratory Failure187.5%
  11. 11Antiphospholipid Syndrome177.1%
  12. 12Arthralgia177.1%
  13. 13Arthritis177.1%
  14. 14Cardiac Tamponade177.1%
  15. 15Cognitive Disorder177.1%

Literature

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Recent PubMed references pinned to Procainamide as a MeSH major topic. Citations link to pubmed.ncbi.nlm.nih.gov.

Clinical trials

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The 10 most recently updated of 17 ClinicalTrials.gov registrations naming Procainamide as an intervention. Registration is not evidence of efficacy or safety — reference crosswalk only.

Pharmacogenomics

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CPIC-curated drug–gene pairs for Procainamide. Levels describe the strength of curated evidence and guideline status — never a recommendation to test or to adjust therapy.

  • NAT2CPIC B/C (provisional)FDA label: Informative PGx

Frequently asked questions

How does Procainamide work?
Mechanism-of-action class: Unknown Cellular or Molecular Interaction.
What is Procainamide used for?
According to FDA labeling, Procainamide carries indications including: 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. Because of the proarrhythmic effects of procainamide, its use with lesser arrhythmias is generally not recommended.. This is a reference summary of labeled uses, not medical advice or a treatment recommendation.
What class of drug is Procainamide?
Procainamide is classified as Antiarrhythmics, class Ia, Antiarrhythmic, Unknown Cellular or Molecular Interaction, Cardiac Rhythm Alteration, Increased Cardiac Muscle Organized Electrical Activity, Negative Inotropy.
What are the contraindications for Procainamide?
Procainamide labeling lists contraindications including: Complete Heart Block: Procainamide should not be administered to patients with complete heart block because of its effects in suppressing nodal or ventricular pacemakers and the hazard of asystole. It may be difficult to recognize complete heart block in patients with ventricular tachycardia, but if significant slowing of ventricular rate occurs during PA treatment without evidence of A-V conduction appearing, PA should be stopped.. Always consult the full prescribing information and a clinician.
Note. Data for procainamide is illustrative MVP content compiled from public sources. pharmacopeia is for educational and informational use only and is not a substitute for professional medical advice.

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