What the FDA labels say about taking them together
Disopyramide and procainamide
Disopyramide's FDA label of August 24, 2026 names procainamide in its drug interactions section, and procainamide's label names disopyramide too. The procainamide label: “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 …”
Check it at the source: the disopyramide FDA label on DailyMed (effective August 24, 2026, Pfizer Laboratories Div Pfizer Inc); the procainamide FDA label on DailyMed (effective February 17, 2025, Caplin Steriles Limited).
What does the disopyramide label say about procainamide?
Disopyramide label, drug interactionsOther antiarrhythmic drugs (e.g., quinidine, procainamide, lidocaine, propranolol) have occasionally been used concurrently with Norpace.
Disopyramide label, warningsConcomitant Antiarrhythmic Therapy The concomitant use of Norpace or Norpace CR with other Type 1A antiarrhythmic agents (such as quinidine or procainamide), Type 1C antiarrhythmics (such as encainide, flecainide or propafenone), and/or propranolol should be reserved for patients with life-threatening arrhythmias who are demonstrably unresponsive to single-agent antiarrhythmic therapy.
Source: FDA drug label (Norpace), Pfizer Laboratories Div Pfizer Inc, effective August 24, 2026 (SPL set e2aa1642-d262-4520-bc6a-9fd3ad795677), via openFDA; the full label on DailyMed
What does the procainamide label say about disopyramide?
Procainamide label, warningsConcurrent 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.
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
These are the labels' own sentences. PlainMeds does not grade interactions; a pharmacist or prescriber can say what they mean for one person's medicines.
Both medicines on the record
| Disopyramide | Procainamide | |
|---|---|---|
| Labeled for | n/a | n/a |
| Boxed warning | Yes | Yes |
| Pharmacy cost (NADAC) | $0.801 per capsule 100 mg capsule | n/a |
| Shortage now | A presentation being discontinued | No current entry |
Source: FDA NDC Directory, CMS NADAC of October 7, 2026 and the FDA Drug Shortage Database (FDA files October 8, 2026)
What next?
- Check more medicines together
- up to five at once