Fentanyl and Naldemedine interaction
Fentanyl and Naldemedine: 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
Management of respiratory depression may include close observation, supportive measures, and use of opioid overdose reversal agents (e.g., naloxone, nalmefene) , depending on the patient's clinical status [see Overdosage (10) ] .
From the Naldemedine (SYMPROIC) label · effective 2025-07-25
Intervention Avoid use of SYMPROIC with another opioid antagonist.
Other opioid antagonists : Potential for additive effect and increased risk of opioid withdrawal; avoid concomitant use ( 7 )
Opioid withdrawal : Consider the overall risk benefit in patients with disruptions to the blood-brain barrier.
Monitor symptoms of opioid withdrawal ( 5.2 )
Opioid Withdrawal Clusters of symptoms consistent with opioid withdrawal, including hyperhidrosis, chills, increased lacrimation, hot flush/flushing, pyrexia, sneezing, feeling cold, abdominal pain, diarrhea, nausea, and vomiting have occurred in patients treated with SYMPROIC [see Adverse Reactions (6.1) ] .
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.