Morphine and Naltrexone: Drug Interaction Guide
Quick answer: This is a major interaction — avoid combining Morphine and Naltrexone unless specifically directed by your doctor.
How Morphine interacts with Naltrexone
Naltrexone is a competitive opioid receptor antagonist that blocks the analgesic effect of morphine and can precipitate acute opioid withdrawal in dependent patients.
What you should do
Stop naltrexone at least 72 hours before planned opioid analgesia. In emergencies, use regional anaesthesia or non-opioid analgesics; if opioid required, titrate carefully under monitoring.
Key facts
Severity
Major — avoid combination
Mechanism
Naltrexone is a competitive opioid receptor antagonist that blocks the analgesic effect of morphine and can precipitate ...
Action
Stop naltrexone at least 72 hours before planned opioid analgesia. In emergencies, use regional anaesthesia or non-opioi...
Frequently asked questions
Can I take Morphine and Naltrexone together?
No — this combination should generally be avoided. Stop naltrexone at least 72 hours before planned opioid analgesia. In emergencies, use regional anaesthesia or non-opioid analgesics; if opioid required, titrate carefully under monitoring.
What is the severity of this interaction?
The interaction between Morphine and Naltrexone is classified as Major — avoid combination. Naltrexone is a competitive opioid receptor antagonist that blocks the analgesic effect of morphine and can precipitate acute opioid withdrawal in dependent patients.
What should I do if I'm prescribed both?
Stop naltrexone at least 72 hours before planned opioid analgesia. In emergencies, use regional anaesthesia or non-opioid analgesics; if opioid required, titrate carefully under monitoring. Always consult your prescribing clinician — do not stop or change medications without medical guidance.
Last reviewed: by iMedic Medical Editorial Team. Our editorial process.