What the FDA labels say about taking them together
Efavirenz and lemborexant
Lemborexant's FDA label of February 24, 2025 names efavirenz in its drug interactions section; the efavirenz label PlainMeds reads does not name lemborexant. The lemborexant label: “Concomitant use with a strong or moderate CYP3A inducer decreases lemborexant exposure, which may reduce DAYVIGO efficacy.”
Check it at the source: the efavirenz FDA label on DailyMed (effective March 31, 2024, Cipla USA Inc.); the lemborexant FDA label on DailyMed (effective February 24, 2025, Eisai Inc.).
What does the efavirenz label say about lemborexant?
Efavirenz's label (effective March 31, 2024) does not name lemborexant in these sections. A label lists what its studies and reports found; it is not a complete list.
Source: FDA drug label (Efavirenz), Cipla USA Inc., effective March 31, 2024 (SPL set 92603fa5-7a2c-4bfb-9a70-aadb4fba952c), via openFDA; the full label on DailyMed
What does the lemborexant label say about efavirenz?
Lemborexant label, drug interactionsStrong and Moderate CYP3A Inducers Clinical Impact: Concomitant use with a strong or moderate CYP3A inducer decreases lemborexant exposure, which may reduce DAYVIGO efficacy. Intervention: Avoid concomitant use of DAYVIGO with strong or moderate CYP3A inducers [see Dosage and Administration ()]. Examples: Strong CYP3A inducers: rifampin, carbamazepine, St. John’s wort Moderate CYP3A inducers: bosentan, efavirenz, etravirine, modafinil
Source: FDA drug label (DAYVIGO), Eisai Inc., effective February 24, 2025 (SPL set 7074cb65-77b3-45d2-8e8d-da8dc0f70bfd), 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
| Efavirenz | Lemborexant | |
|---|---|---|
| Labeled for | HIV | Insomnia |
| Boxed warning | No | No |
| Pharmacy cost (NADAC) | $1.28 per tablet 600 mg tablet | $11.57 per tablet 10 mg tablet |
| Shortage now | No current entry | 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