2023 Volume 30 Issue 12 Pages 288-291
Case 1: A man in his 50s. He had been treated for lung adenocarcinoma and skull base metastasis. The dose of oxycodone was increased and naldemedine was started in combination. He continued to experience pain, and nausea and vomiting appeared. Naldemedine was suspected to have an antagonistic effect and was discontinued. From the next day, his nausea and vomiting disappeared. Case 2: A female in her 40s. She had multiple mass lesions due to multiple schwannomas in the dural sac and epidural mater. She had severe pain in the abdomen and both limbs. After controlling her pain with a fentanyl patch, her constipation worsened, and she was administered naldemedine. Within hours of taking naldemedine, she had nausea and terrible diarrhea. Two years later, she was diagnosed with a right cerebellar pontine angle tumor. Conclusion: When reduced analgesic effect and withdrawal symptoms are suspected after administration of naldemedine with an opioid, the patient should be evaluated for the possible presence of brain tumor.
