Fentanyl and Lenacapavir interaction
Fentanyl and Lenacapavir: both prescribing labels flag this combination with the strongest language, such as a contraindication, a boxed warning, or an instruction to avoid it.
Do not combine without a prescriber's guidance. The label language below is the strongest FDA uses.
What the FDA labels say
From the Fentanyl (FENTANYL CITRATE) label · effective 2026-04-07
• Concomitant use with CYP3A4 inhibitors (or discontinuation of CYP3A4 inducers) can result in a fatal overdose of fentanyl.
Cytochrome P450 3A4 Interaction The concomitant use of Fentanyl Citrate Injection with all cytochrome P450 3A4 inhibitors may result in an increase in fentanyl plasma concentrations, which could increase or prolong adverse reactions and may cause potentially fatal respiratory depression.
Monitor patients receiving Fentanyl Citrate Injection and any CYP3A4 inhibitor or inducer [see Warnings and Precautions (5.4) , Drug Interactions (7) , Clinical Pharmacology (12.3) ] .
Risks of Concomitant Use or Discontinuation of Cytochrome P450 3A4 Inhibitors and Inducers Concomitant use of Fentanyl Citrate Injection with a CYP3A4 inhibitor, such as macrolide antibiotics (e.g., erythromycin), azole-antifungal agents (e.g., ketoconazole), and protease inhibitors (e.g., ritonavir), may increase plasma concentrations of fentanyl and prolong…
When using Fentanyl Citrate Injection with CYP3A4 inhibitors or discontinuing CYP3A4 inducers in Fentanyl Citrate Injection-treated patients, monitor patients closely at frequent intervals and consider dosage reduction of Fentanyl Citrate Injection [see Dosage and Administration (2.1) , Drug Interactions (7) ] .
From the Lenacapavir (Sunlenca) label · effective 2026-08-27
Narcotic analgesics metabolized by CYP3A: e.g., fentanyl, oxycodone ↑ fentanyl ↑ oxycodone Careful monitoring of therapeutic effects and adverse reactions associated with CYP3A-metabolized narcotic analgesics (including potentially fatal respiratory depression) is recommended with co-administration. tramadol ↑ tramadol A decrease in dose may be needed for tramadol…
Opioid Antagonist: naloxegol ↑ naloxegol Avoid use with SUNLENCA; if unavoidable, decrease the dosage of naloxegol and monitor for adverse reactions.
Narcotic analgesic for treatment of opioid dependence: buprenorphine, methadone buprenorphine: effects unknown methadone: effects unknown Initiation of buprenorphine or methadone in patients taking SUNLENCA: Carefully titrate the dose of buprenorphine or methadone to the desired effect; use the lowest feasible initial or maintenance dose.
Sedatives/Hypnotics: midazolam (oral) triazolam ↑ midazolam (oral) ↑ triazolam Use with caution when midazolam or triazolam is concomitantly administered with SUNLENCA 7.4 Drugs without Clinically Significant Interactions with SUNLENCA Based on drug interaction studies conducted with SUNLENCA, no clinically significant drug interactions have been observed with:…
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Open in the checkerNot medical advice. Interaction Checker quotes FDA label text and NIH fact sheets. Whether an interaction matters for you depends on doses, timing, kidney and liver function, and other conditions. Confirm with a pharmacist or prescriber.