What the FDA labels say about taking them together
Etravirine and phenytoin
Etravirine's FDA label of August 15, 2023 names phenytoin in its drug interactions section; the phenytoin labels PlainMeds reads (2) do not name etravirine. The etravirine label: “Carbamazepine, phenobarbital and phenytoin are inducers of CYP450 enzymes. INTELENCE should not be used in combination with carbamazepine, phenobarbital, or phenytoin as co-administration may cause significant decreases …”
Check it at the source: the etravirine FDA label on DailyMed (effective August 15, 2023, Janssen Products LP); the phenytoin FDA label on DailyMed (effective October 15, 2024, Mylan Pharmaceuticals Inc.).
What does the etravirine label say about phenytoin?
Etravirine label, drug interactionsConcomitant Drug Class/Drug Name: Anticonvulsants: carbamazepine phenobarbital phenytoin; Effect on Concentration of Etravirine or Concomitant Drug: ↓ etravirine; Clinical Comment: Carbamazepine, phenobarbital and phenytoin are inducers of CYP450 enzymes. INTELENCE should not be used in combination with carbamazepine, phenobarbital, or phenytoin as co-administration may cause significant decreases in etravirine plasma concentrations and loss of therapeutic effect of INTELENCE.
Source: FDA drug label (Intelence), Janssen Products LP, effective August 15, 2023 (SPL set 6a9cbc29-9f15-4b24-8d86-206b82887f3d), via openFDA; the full label on DailyMed
What does the phenytoin label say about etravirine?
Phenytoin's label (effective October 15, 2024) and its 1 other brand-application label do not name etravirine 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
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
| Etravirine | Phenytoin | |
|---|---|---|
| Labeled for | HIV | Seizures and epilepsy |
| Boxed warning | No | No |
| Pharmacy cost (NADAC) | $9.94 per tablet 200 mg tablet | $0.145 per capsule 100 mg capsule |
| 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