What the FDA labels say about taking them together
Propranolol and thioridazine
Propranolol's FDA label of January 15, 2026 names thioridazine in its drug interactions section, and thioridazine's label names propranolol too. The thioridazine label: “Reduced cytochrome P450 2D6 isozyme activity drugs that inhibit this isozyme and certain other drugs appear to appreciably inhibit the metabolism of thioridazine.”
Check it at the source: the propranolol FDA label on DailyMed (effective January 15, 2026, Mylan Pharmaceuticals Inc.); the thioridazine FDA label on DailyMed (effective November 11, 2025, Mylan Institutional Inc.).
What does the propranolol label say about thioridazine?
Propranolol label, drug interactionsNeuroleptic Drugs Co-administration of long-acting propranolol at doses greater than or equal to 160 mg/day resulted in increased thioridazine plasma concentrations ranging from 55% to 369% and increased thioridazine metabolite (mesoridazine) concentrations ranging from 33% to 209%.
Source: FDA drug label (Propranolol Hydrochloride Er, NDA018553), ANI Pharmaceuticals, Inc., effective August 27, 2026 (SPL set 5415904b-90da-48e8-9f9e-f86749aa129c), via openFDA
Source: FDA drug label (Propranolol Hydrochloride), Mylan Pharmaceuticals Inc., effective January 15, 2026 (SPL set b94dcec7-7633-4a33-9cea-48161adeaf93), via openFDA; the full label on DailyMed
What does the thioridazine label say about propranolol?
Thioridazine label, contraindicationsReduced cytochrome P450 2D6 isozyme activity drugs that inhibit this isozyme (e.g., fluoxetine and paroxetine) and certain other drugs (e.g., fluvoxamine, propranolol, and pindolol) appear to appreciably inhibit the metabolism of thioridazine.
Source: FDA drug label (Thioridazine Hydrochloride), Mylan Institutional Inc., effective November 11, 2025 (SPL set 52fea941-0b47-41c1-b00d-f88150e8ab93), 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
| Propranolol | Thioridazine | |
|---|---|---|
| Labeled for | High blood pressure, Angina, Atrial fibrillation, Migraine | n/a |
| Boxed warning | No | Yes |
| Pharmacy cost (NADAC) | $0.0493 per tablet 20 mg tablet | $0.571 per tablet 25 mg tablet |
| Shortage now | In shortage | 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