What the FDA labels say about taking them together
Doravirine/islatravir and gemcitabine
Doravirine/islatravir's FDA label of April 20, 2026 names gemcitabine in its drug interactions section; the gemcitabine labels PlainMeds reads (4) do not name doravirine/islatravir. The doravirine/islatravir label: “Co-administration with these nucleoside antimetabolites is not recommended as dCK substrates may cause a decrease in the intracellular concentration of ISL-TP.”
Check it at the source: the doravirine/islatravir FDA label on DailyMed (effective April 20, 2026, Merck Sharp & Dohme LLC); the gemcitabine FDA label on DailyMed (effective October 14, 2024, Fresenius Kabi USA, LLC).
What does the doravirine/islatravir label say about gemcitabine?
Doravirine/islatravir label, drug interactionsConcomitant Drug Class/Drug Name: Nucleoside Antimetabolites cladribine clofarabine cytarabine fludarabine gemcitabine; Effect on Concentration: ↓ ISL-TP; Clinical Comment: Co-administration with these nucleoside antimetabolites is not recommended as dCK substrates may cause a decrease in the intracellular concentration of ISL-TP.
Source: FDA drug label (IDVYNSO), NDA216964 (Msd), as published by Merck Sharp & Dohme LLC, effective April 20, 2026 (SPL set 11aaeb53-9848-433c-be7f-db8a5bc0b26f), via openFDA; the full label on DailyMed
What does the gemcitabine label say about doravirine/islatravir?
Gemcitabine's label (effective October 14, 2024) and its 3 other brand-application labels do not name doravirine/islatravir in these sections. A label lists what its studies and reports found; it is not a complete list.
Source: FDA drug label (GEMCITABINE), Fresenius Kabi USA, LLC, effective October 14, 2024 (SPL set c550dd16-a5e8-44be-87f2-210c15bbb513), 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
| Doravirine/islatravir | Gemcitabine | |
|---|---|---|
| Labeled for | HIV | Breast cancer, Lung cancer |
| Boxed warning | No | No |
| Pharmacy cost (NADAC) | n/a | n/a |
| 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