What the FDA labels say about taking them together
Fentanyl and lenacapavir
Lenacapavir's FDA label of August 27, 2026 names fentanyl in its drug interactions section; the fentanyl labels PlainMeds reads (2) do not name lenacapavir. The lenacapavir label: “Careful monitoring of therapeutic effects and adverse reactions associated with CYP3A-metabolized narcotic analgesics is recommended with co-administration.”
Check it at the source: the fentanyl FDA label on DailyMed (effective March 6, 2026, Hikma Pharmaceuticals USA Inc.); the lenacapavir FDA label on DailyMed (effective August 27, 2026, Gilead Sciences, Inc.).
What does the fentanyl label say about lenacapavir?
Fentanyl's label (effective March 6, 2026) and its 1 other brand-application label do not name lenacapavir in these sections. A label lists what its studies and reports found; it is not a complete list.
Source: FDA drug label (Fentanyl Citrate), Hikma Pharmaceuticals USA Inc., effective March 6, 2026 (SPL set ce5db1c2-feb1-4ad2-847a-d02e865bd47e), via openFDA; the full label on DailyMed
What does the lenacapavir label say about fentanyl?
Lenacapavir label, drug interactionsConcomitant Drug Class/Drug Name: Narcotic analgesics metabolized by CYP3A: e.g., fentanyl, oxycodone; Effect on Concentration ↑ = Increase, ↓ = Decrease.: ↑ fentanyl ↑ oxycodone; Clinical Comment: Careful monitoring of therapeutic effects and adverse reactions associated with CYP3A-metabolized narcotic analgesics (including potentially fatal respiratory depression) is recommended with co-administration.
Source: FDA drug label (Sunlenca), Gilead Sciences, Inc., effective August 27, 2026 (SPL set e5652804-29c4-40d7-aeb2-0142ed2a7b5b), 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
| Fentanyl | Lenacapavir | |
|---|---|---|
| Labeled for | Pain | HIV |
| Boxed warning | Yes | No |
| Pharmacy cost (NADAC) | $1.79 per mL 100 mcg/2 mL vial | n/a |
| Shortage now | In shortage | 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