Procainamide side effects: what 241 FDA adverse event reports show
Drug class
Not stated in label
Label matched
Procainamide Hydrochloride (Procainamide Hydrochloride)
Who reports
241 reports · 91% serious · 23 with death outcome · 46% female
Used for
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.
What it is
DESCRIPTION Procainamide Hydrochloride Injection, USP is a sterile, nonpyrogenic solution of procainamide hydrochloride in water for injection. Each milliliter of the 2 mL vial contains procainamide hydrochloride 500 mg; methylparaben 1 mg and sodium metabisulfite 1.8 mg added in water for injection.
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.
Causality screen of the 10 strongest signals
What the badges mean
- Labeled — boxed warning The term (or its clinical synonym) appears in the FDA boxed warning: causality is regulator-recognised and considered serious.
- Likely indication confounding The term appears in the label's indications: reports probably describe the disease being treated (or its progression), not a drug effect. Classic confounding by indication.
- Not in label — unassessed Not found in the label text, not an artifact pattern. This is a genuine candidate for a formal causality assessment (Bradford Hill / WHO-UMC); it has NOT had one here.
Strongest disproportionality signals
Flagged terms (PRR ≥ 2, χ² ≥ 4, n ≥ 10), ranked by PRR; infinite PRRs (no comparator reports) excluded. The EBGM column is a second, shrinkage-based estimate (MGPS) with its 5th percentile EB05 and the BCPNN IC025; a pair flagged by PRR alone is marked PRR-only and should be read as fragile. The strata column recomputes the PRR on serious reports only and flags pairs whose reports are unusually skewed by sex or come mostly from consumers rather than clinicians. 0 further terms are in the interactive explorer. Reaction links open the term's cross-drug page.
| Reaction | Reports | PRR 95% CI · ROR · χ²/p | EBGM EB05 · IC025 | Label screen | Serious-only & strata | Trial cross-check |
|---|---|---|---|---|---|---|
| Photosensitivity reaction (sun sensitivity) | 16 | 84.7 52.7–136.0ROR 90.6 · χ² 1,240 / p 5e-272 | 77.1 EB05 50.3 · IC025 +3.7 3/3 methods agree | Not in label — unassessed | serious PRR 84.9 | no trial data cached |
| Peritonitis | 17 | 71.5 45.2–113.0ROR 76.8 · χ² 1,112 / p 4e-244 | 66.3 EB05 43.9 · IC025 +3.8 3/3 methods agree | Not in label — unassessed | serious PRR 45.3 | no trial data cached |
| Intervertebral disc protrusion | 17 | 67.5 42.7–106.8ROR 72.6 · χ² 1,049 / p 2e-230 | 62.9 EB05 41.6 · IC025 +3.7 3/3 methods agree | Not in label — unassessed | serious PRR 50.0 | no trial data cached |
| Ventricular tachycardia | 11 | 57.8 32.4–103.0ROR 60.5 · χ² 558 / p 9e-124 | 52.8 EB05 31.4 · IC025 +3.0 3/3 methods agree | Likely indication confounding term in indications; also in warnings | serious PRR 36.9 | no trial data cached |
| Ascites | 18 | 53.3 34.2–83.1ROR 57.5 · χ² 872 / p 5e-192 | 50.6 EB05 33.8 · IC025 +3.7 3/3 methods agree | Not in label — unassessed | serious PRR 34.2 | no trial data cached |
| Frequent bowel movements | 16 | 51.8 32.2–83.1ROR 55.4 · χ² 747 / p 8e-165 | 48.9 EB05 31.9 · IC025 +3.5 3/3 methods agree | Not in label — unassessed | serious PRR 50.6 | no trial data cached |
| Systemic lupus erythematosus | 19 | 46.8 30.4–72.0ROR 50.7 · χ² 806 / p 1e-177 | 44.8 EB05 30.3 · IC025 +3.7 3/3 methods agree | Labeled — boxed warning synonym match | serious PRR 30.4 | no trial data cached |
| Sinus bradycardia | 5 | 44.9 18.9–107.0ROR 45.9 · χ² 173 / p 8e-40 | 38.3 EB05 16.9 · IC025 +1.6 3/3 methods agree | Not in label — unassessed | serious PRR 29.3 | no trial data cached |
| Electrocardiogram qt prolonged | 18 | 43.5 27.9–67.9ROR 47.0 · χ² 707 / p 5e-156 | 41.7 EB05 27.9 · IC025 +3.5 3/3 methods agree | Not in label — unassessed | serious PRR 28.0 | no trial data cached |
| Colitis ulcerative | 17 | 33.2 21.0–52.5ROR 35.6 · χ² 500 / p 6e-111 | 32.1 EB05 21.2 · IC025 +3.3 3/3 methods agree | Not in label — unassessed | serious PRR 22.6 | no trial data cached |
Trial evidence (ClinicalTrials.gov)
Most frequently reported reactions
By raw co-report count, regardless of disproportionality. Common terms here are often the illness itself or generic outcomes.
| Reaction | Reports | PRR 95% CI · ROR · χ²/p | EBGM EB05 · IC025 | Label screen | Serious-only & strata | Trial cross-check |
|---|---|---|---|---|---|---|
| Systemic lupus erythematosus | 19 | 46.8 30.4–72.0ROR 50.7 · χ² 806 / p 1e-177 | 44.8 EB05 30.3 · IC025 +3.7 3/3 methods agree | Labeled — boxed warning synonym match | serious PRR 30.4 | no trial data cached |
| Electrocardiogram qt prolonged | 18 | 43.5 27.9–67.9ROR 47.0 · χ² 707 / p 5e-156 | 41.7 EB05 27.9 · IC025 +3.5 3/3 methods agree | Not in label — unassessed | serious PRR 28.0 | no trial data cached |
| Ascites | 18 | 53.3 34.2–83.1ROR 57.5 · χ² 872 / p 5e-192 | 50.6 EB05 33.8 · IC025 +3.7 3/3 methods agree | Not in label — unassessed | serious PRR 34.2 | no trial data cached |
| Colitis ulcerative | 17 | 33.2 21.0–52.5ROR 35.6 · χ² 500 / p 6e-111 | 32.1 EB05 21.2 · IC025 +3.3 3/3 methods agree | Not in label — unassessed | serious PRR 22.6 | no trial data cached |
| Intervertebral disc protrusion | 17 | 67.5 42.7–106.8ROR 72.6 · χ² 1,049 / p 2e-230 | 62.9 EB05 41.6 · IC025 +3.7 3/3 methods agree | Not in label — unassessed | serious PRR 50.0 | no trial data cached |
| Peritonitis | 17 | 71.5 45.2–113.0ROR 76.8 · χ² 1,112 / p 4e-244 | 66.3 EB05 43.9 · IC025 +3.8 3/3 methods agree | Not in label — unassessed | serious PRR 45.3 | no trial data cached |
| Frequent bowel movements | 16 | 51.8 32.2–83.1ROR 55.4 · χ² 747 / p 8e-165 | 48.9 EB05 31.9 · IC025 +3.5 3/3 methods agree | Not in label — unassessed | serious PRR 50.6 | no trial data cached |
| Photosensitivity reaction (sun sensitivity) | 16 | 84.7 52.7–136.0ROR 90.6 · χ² 1,240 / p 5e-272 | 77.1 EB05 50.3 · IC025 +3.7 3/3 methods agree | Not in label — unassessed | serious PRR 84.9 | no trial data cached |
| Ventricular tachycardia | 11 | 57.8 32.4–103.0ROR 60.5 · χ² 558 / p 9e-124 | 52.8 EB05 31.4 · IC025 +3.0 3/3 methods agree | Likely indication confounding term in indications; also in warnings | serious PRR 36.9 | no trial data cached |
| Sinus bradycardia | 5 | 44.9 18.9–107.0ROR 45.9 · χ² 173 / p 8e-40 | 38.3 EB05 16.9 · IC025 +1.6 3/3 methods agree | Not in label — unassessed | serious PRR 29.3 | no trial data cached |
Unlabeled candidate signals
Every screened signal with n ≥ 20 was either labeled, an indication term, or an artifact pattern — no unlabeled candidate stood out in the top signals.
Want to assess one of these properly? The runbook describes the Bradford Hill / trial-evidence workflow used on the assessment page, and handoff_top1000_signals.csv lists the strongest unassessed pairs across all drugs.
Common questions
What are the most reported side effects of Procainamide?
In FDA FAERS, the most frequently co-reported reaction terms for Procainamide are systemic lupus erythematosus, electrocardiogram qt prolonged, ascites, colitis ulcerative, intervertebral disc protrusion, peritonitis. These are report counts, not rates: FAERS has no denominator, reporting is voluntary and uneven, and a term can be reported because of the illness being treated rather than the drug.
Does Procainamide have an FDA boxed warning?
Yes. The current FDA label carries a 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.
Do FAERS signals prove that Procainamide causes these side effects?
No. A disproportionality signal (PRR, ROR) means a reaction is reported more often with this drug than with others in the database. That can reflect a real effect, but also the disease being treated, stimulated reporting after news or litigation, co-medications, or how reports are coded. Causality needs temporality, dose-response, biological plausibility, consistency across data sources and, ideally, trial or cohort evidence. This page screens each term against the FDA label and ClinicalTrials.gov results; it does not establish causation.
Sources & methods
- FDA label via openFDA (set ID 358c956e-8c6c-4bd6-a6bc-194d5b3d6d9a, effective 20241218; matched on
openfda.generic_name.exact:"PROCAINAMIDE HYDROCHLORIDE") - Bayesian shrinkage measures computed offline over all 1,317,300 cached pairs: BCPNN information component (IC, with Norén closed-form IC025) and MGPS empirical-Bayes geometric mean (EBGM, EB05) with a two-component gamma prior fitted by maximum marginal likelihood (α₁=0.57, β₁=0.02, α₂=1.42, β₂=0.70, w=0.17); unstratified
- FAERS pair statistics from the OpenPV build of 2026-09-14 (openFDA
count=aggregation, fieldpatient.drug.openfda.generic_name.exact, 10 reaction terms, min 3 co-reports); PRR/ROR with 95% CI, chi-square with Yates correction - Serious-only and stratified counts (serious:1, patient.patientsex, primarysource.qualification) from openFDA count queries; serious-only PRR uses the drug serious report total and the term global serious total (N_serious=11,882,979); strata shown only when n ≥ 20
- Seriousness and sex counts from openFDA
count=serious,patient.patientsex,seriousnessdeath
Page generated 2026-10-08. Label and PubChem text are retrieved automatically and may lag the current label; always check the current prescribing information. OpenPV is a beta research tool of the Open Source Medicine Foundation.