Lofexidine and Nalmefene interaction
Lofexidine and Nalmefene: 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 Nalmefene (Zurnai) label · effective 2026-07-31
Risk of Recurrent Respiratory and CNS Depression : A recurrence of respiratory depression is possible, therefore, keep the patient under continued surveillance and administer repeat doses of ZURNAI using a new auto-injector with each dose while awaiting emergency medical assistance.
From the Lofexidine label · effective 2026-07-22
Oral Naltrexone : Concomitant use may reduce efficacy of oral naltrexone.
It is possible that oral naltrexone efficacy may be reduced if used concomitantly within 2 hours of Lofexidine tablets.
Oral Naltrexone Coadministration of Lofexidine tablets and oral naltrexone resulted in statistically significant differences in the steady-state pharmacokinetics of naltrexone.
This interaction is not expected if naltrexone is administered by non-oral routes [see Clinical Pharmacology (12.3) ] .
Taking more than these two? Interactions stack. Check your whole list at once; it stays in your browser.
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.