Morphine and Naltrexone: interaction and safety
This source-based reference is not a personal treatment recommendation. The relevance and management of an interaction depend on the exact products, route, dose and clinical situation.
Interaction mechanism
Opioid-receptor antagonism can block analgesia or precipitate withdrawal.
Clinical significance and safety
Naltrexone blocks opioid receptors and can reduce morphine effects or precipitate abrupt withdrawal in an opioid-dependent patient. The naltrexone label contraindicates treatment in people receiving opioid analgesics or maintained on opioids such as methadone. A specialist must coordinate any transition; do not independently start naltrexone or stop established opioid treatment.
Using this information
This is a source-based reference record, not a recommendation to combine, stop or change medicines. A missing interaction record does not establish safe use. A qualified healthcare professional should consider the exact products, doses, other medicines and individual health circumstances.