What the FDA labels say about taking them together
Fenoprofen and phenobarbital
Fenoprofen's FDA label of August 20, 2026 names phenobarbital in its drug interactions section; the phenobarbital labels PlainMeds reads (2) do not name fenoprofen. The fenoprofen label: “Chronic administration of phenobarbital, a known enzyme inducer, may be associated with a decrease in the plasma half-life of fenoprofen.”
Check it at the source: the fenoprofen FDA label on DailyMed (effective August 20, 2026, Misemer Pharmaceuticals, Inc.); the phenobarbital FDA label on DailyMed (effective August 27, 2026).
What does the fenoprofen label say about phenobarbital?
Fenoprofen label, drug interactionsPhenobarbital Clinical Impact: Chronic administration of phenobarbital, a known enzyme inducer, may be associated with a decrease in the plasma half-life of fenoprofen. Intervention: When phenobarbital is added to or withdrawn from treatment, dosage adjustment of FENOPROFEN CALCIUM may be required.
Source: FDA drug label (Fenoprofen Calcium), Misemer Pharmaceuticals, Inc., effective August 20, 2026 (SPL set d33ad329-1ca6-ac2e-e053-2995a90a15c5), via openFDA; the full label on DailyMed
What does the phenobarbital label say about fenoprofen?
Phenobarbital's label (effective August 27, 2026) and its 1 other brand-application label do not name fenoprofen in these sections. A label lists what its studies and reports found; it is not a complete list.
Source: FDA drug label (Phenobarbital), Chartwell RX, LLC, effective August 27, 2026 (SPL set 74428144-fb24-40a5-a670-3b876e2d116c), 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
| Fenoprofen | Phenobarbital | |
|---|---|---|
| Labeled for | Pain, Rheumatoid arthritis, Osteoarthritis | Seizures and epilepsy |
| Boxed warning | Yes | No |
| Pharmacy cost (NADAC) | n/a | $0.213 per tablet 100 mg tablet |
| Shortage now | No current entry | A presentation being discontinued |
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