What the FDA labels say about taking them together
Prazosin and procainamide
Prazosin's FDA label of March 6, 2026 names procainamide in its drug interactions section; the procainamide label PlainMeds reads does not name prazosin.
Check it at the source: the prazosin FDA label on DailyMed (effective March 6, 2026, Prasco Laboratories); the procainamide FDA label on DailyMed (effective February 17, 2025, Caplin Steriles Limited).
What does the prazosin label say about procainamide?
Prazosin label, drug interactionsDrug Interactions Prazosin hydrochloride capsules have been administered without any adverse drug interaction in limited clinical experience to date with the following: (1) cardiac glycosides– digitalis and digoxin; (2) hypoglycemics–insulin, chlorpropamide, phenformin, tolazamide, and tolbutamide; (3) tranquilizers and sedatives–chlordiazepoxide, diazepam, and phenobarbital; (4) antigout–allopurinol, colchicine, and probenecid; (5) antiarrhythmics–procainamide, propranolol (see WARNINGS however), and quinidine; and (6) analgesics, antipyretics and anti-inflammatories–propoxyphene, aspirin, indomethacin, and phenylbutazone.
Source: FDA drug label (Prazosin Hydrochloride), NDA017442 (Pfizer), as published by Prasco Laboratories, effective March 6, 2026 (SPL set cbe89216-7dea-43d7-b12e-44ccfb69af3d), via openFDA; the full label on DailyMed
What does the procainamide label say about prazosin?
Procainamide's label (effective February 17, 2025) does not name prazosin in these sections. A label lists what its studies and reports found; it is not a complete list.
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
| Prazosin | Procainamide | |
|---|---|---|
| Labeled for | High blood pressure | n/a |
| Boxed warning | No | Yes |
| Pharmacy cost (NADAC) | $0.0842 per capsule 1 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