Prescription medicine

Procainamide First approved as Pronestyl

Procainamide (Pronestyl) is a prescription medicine with an FDA approval on record since 1950. FDA's NDC Directory lists it from 11 generic labelers.

Generic listed
Boxed warning

Check it at the source: the procainamide FDA label on DailyMed (effective February 17, 2025, Caplin Steriles Limited); the NDA 7335 record on Drugs@FDA; every procainamide label on DailyMed.

Highlights of the record

FDA label of February 17, 2025; NDC Directory, Drugs@FDA and Orange Book, October 8, 2026

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.

Used for

From the label: indications and usage
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.

Forms and strengths

100 mg/ml
500 mg/ml

Injection (solution); injection.

On the market

Earliest approval on file: June 2, 1950 Pronestyl, Apothecon; Drugs@FDA’s file, where older or withdrawn approvals can be missing
Generic approvals: 45 first December 2, 1976; 5 with a marketed status in Drugs@FDA
Labelers listed (NDC): 11 of which 11 under generic applications, 0 under brand applications, repackagers included

Supply and safety

Pharmacy cost (NADAC): Not in the survey
Shortage (FDA): No current entry
Recalls by its makers (FDA): No recall recorded
FAERS reports: 241 through July 30, 2026

What is procainamide used for?

From the label: indications and usage
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. Treatment of patients with asymptomatic ventricular premature contractions should be avoided. Initiation of procainamide treatment, as with other antiarrhythmic agents used to treat life-threatening arrhythmias, should be carried out in the hospital. Antiarrhythmic drugs have not been shown to enhance survival in patients with ventricular arrhythmias. […]

FDA pharmacologic class: Antiarrhythmic.

Source: FDA drug label (Procainamide Hydrochloride), Caplin Steriles Limited, effective February 17, 2025 (SPL set fcaa5e9a-3c8a-4796-aa87-626268b6cf60), via openFDA; the full label on DailyMed

Is there a generic for procainamide (Pronestyl)?

The FDA approved the first generic procainamide on December 2, 1976. 45 generic applications are approved; 5 of them carry a current (not discontinued) marketing status in Drugs@FDA; that status is not evidence that the generic is on sale.

FDA's NDC Directory lists procainamide from 11 labelers under a generic (ANDA) application. A listing means the company has registered the product for sale; it does not show that every pharmacy stocks it.

1950 earliest approval on file
1976 first generic approved

Source: Drugs@FDA, FDA NDC Directory and the Orange Book (openFDA bulk files, October 8, 2026)

What does the procainamide label say about other medicines?

The procainamide label names 6 other medicines in its interaction, contraindication or warning sections. The labels of 47 other medicines name procainamide. The sentences are the labels' own; a label lists what its studies and reports found, not every interaction.

Medicine named	Section	What the label says
Disopyramide	warnings	Concurrent Other Antiarrhythmic Agents Concurrent use of PA with other Group 1A antiarrhythmic agents such as quinidine or disopyramide may produce enhanced prolongation of conduction or depression of contractility and hypotension, especially in patients with cardiac decompensation.
Flecainide	warnings	… 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%).
Lidocaine	warnings	Therefore, use of procainamide should be considered only if discontinuation of digitalis, and therapy with potassium, lidocaine, or phenytoin are ineffective.
Phenytoin	warnings	Therefore, use of procainamide should be considered only if discontinuation of digitalis, and therapy with potassium, lidocaine, or phenytoin are ineffective.
Quinidine	drug interactions	Anticholinergic drugs administered concurrently with PA may produce additive antivagal effects on A-V nodal conduction, although this is not as well documented for PA as for quinidine.
Succinylcholine	drug interactions	Patients taking PA who require neuromuscular blocking agents such as succinylcholine may require less than usual doses of the latter, due to PA effects on reducing acetylcholine release.

Other labels that name procainamide

Check procainamide against other medicines

Source: FDA drug label (Procainamide Hydrochloride), Caplin Steriles Limited, effective February 17, 2025 (SPL set fcaa5e9a-3c8a-4796-aa87-626268b6cf60), via openFDA; the full label on DailyMed

What do FAERS reports show for procainamide?

The FDA Adverse Event Reporting System holds 241 reports that list procainamide among the medicines taken, through July 30, 2026, each a report of something that happened, not proof the medicine caused it; 23 are coded as a death and 123 as a hospital stay. Counts follow how widely a medicine is used and watched, and they are not a measure of how risky it is.

The most reported reactions

Drug Ineffective (a use or a product term, not a reaction)94
Off Label Use (a use or a product term, not a reaction)32
Atrial Fibrillation (named in the label)21
Maternal Exposure During Pregnancy (a use or a product term, not a reaction)19
Systemic Lupus Erythematosus19
Ascites18
Drug Ineffective For Unapproved Indication (a use or a product term, not a reaction)18
Electrocardiogram Qt Prolonged18

Side effects: the label's list and every FAERS reaction

Source: FDA Adverse Event Reporting System (FAERS) via openFDA, reports through July 30, 2026

What next?

Other antiarrhythmics: the pharmacologic class, with prices and generics
Procainamide side effects: the label's list beside FAERS reports
Check an interaction: what two or more labels say about each other