What the FDA labels say about taking them together
Phenytoin and propranolol
Propranolol's FDA label of January 15, 2026 names phenytoin in its drug interactions section; the phenytoin labels PlainMeds reads (2) do not name propranolol. The propranolol label: “CYP1A2 inducers (phenytoin, phenobarbital) or CYP2C19 inducers (rifampin) decrease propranolol plasma concentration when co-administered.”
Check it at the source: the phenytoin FDA label on DailyMed (effective October 15, 2024, Mylan Pharmaceuticals Inc.); the propranolol FDA label on DailyMed (effective January 15, 2026, Mylan Pharmaceuticals Inc.).
What does the phenytoin label say about propranolol?
Phenytoin's label (effective October 15, 2024) and its 1 other brand-application label do not name propranolol in these sections. A label lists what its studies and reports found; it is not a complete list.
Source: FDA drug label (Phenytek), Mylan Pharmaceuticals Inc., effective October 15, 2024 (SPL set 0f94c791-8b07-4b41-927e-c9f28bec5f60), via openFDA; the full label on DailyMed
What does the propranolol label say about phenytoin?
Propranolol label, drug interactionsInducers of Hepatic Drug Metabolism Blood levels of propranolol may be decreased by co-administration with inducers such as rifampin, ethanol, phenytoin, and phenobarbital.
Inderal Xl label (ANI Pharmaceuticals, Inc., August 27, 2026), drug interactionsCYP1A2 and CYP2C19 Inducers: CYP1A2 inducers (e.g., phenytoin, montelukast, smoking) and CYP2C19 inducers (e.g. rifampin) decrease the plasma levels of propranolol resulting in a loss of efficacy [see Clinical Pharmacology ( 12.7 )].
Hemangeol label (Pierre Fabre Pharmaceuticals, Inc., June 25, 2026), drug interactionsCYP1A2 inducers (phenytoin, phenobarbital) or CYP2C19 inducers (rifampin) decrease propranolol plasma concentration when co-administered.
Source: FDA drug label (Inderal Xl, NDA021438), ANI Pharmaceuticals, Inc., effective August 27, 2026 (SPL set ac196ff5-9215-402b-bc57-69aa87f8bade), via openFDA
Source: FDA drug label (Hemangeol, NDA205410), Pierre Fabre Pharmaceuticals, Inc., effective June 25, 2026 (SPL set b6f9dd2a-632b-87eb-70f0-b2064d7ed48a), 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
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
| Phenytoin | Propranolol | |
|---|---|---|
| Labeled for | Seizures and epilepsy | High blood pressure, Angina, Atrial fibrillation, Migraine |
| Boxed warning | No | No |
| Pharmacy cost (NADAC) | $0.145 per capsule 100 mg capsule | $0.0493 per tablet 20 mg tablet |
| Shortage now | No current entry | In shortage |
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