Nalmefene and Promethazine and codeine interaction
Nalmefene and Promethazine and codeine: 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.
In neonates, opioid withdrawal may be life-threatening if not recognized and properly treated.
While the duration of action of nalmefene is as long as most opioids, a recurrence of respiratory depression is possible, even after an apparently adequate initial response to ZURNAI treatment [see Clinical Pharmacology (12.3) ].
In neonates, opioid withdrawal may be life-threatening if not recognized and properly treated and may include the following signs and symptoms: convulsions, excessive crying, and hyperactive reflexes.
There may be clinical settings, particularly the postpartum period in neonates with known or suspected exposure to maternal opioid use, where it is preferable to avoid the abrupt precipitation of opioid withdrawal symptoms.
From the Promethazine and codeine (Promethazine Hydrochloride and Codeine Phosphate) label · effective 2025-12-18
Management of respiratory depression includes discontinuation of Promethazine HCl and Codeine Phosphate Oral Solution, close observation, supportive measures, and use of opioid antagonists (e.g. naloxone), depending on the patient’s clinical status [ see Overdosage (10) ].
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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.