What the FDA labels say about taking them together
Etravirine and phenobarbital
Etravirine's FDA label of August 15, 2023 names phenobarbital in its drug interactions section; the phenobarbital 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 phenobarbital FDA label on DailyMed (effective August 27, 2026).
What does the etravirine label say about phenobarbital?
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 phenobarbital label say about etravirine?
Phenobarbital's label (effective August 27, 2026) 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 (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
| Etravirine | Phenobarbital | |
|---|---|---|
| Labeled for | HIV | Seizures and epilepsy |
| Boxed warning | No | No |
| Pharmacy cost (NADAC) | $9.94 per tablet 200 mg tablet | $0.213 per tablet 100 mg tablet |
| Shortage now | A presentation being discontinued | 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