Opioid withdrawal syndrome induced by naldemedine administration in a cancer patient without brain metastasis.

Abstract

Objectives: Naldemedine is a peripherally acting μ-opioid receptor antagonist used to treat opioid-induced constipation. As this drug does not cross the blood-brain barrier, it is believed that patients without brain metastases do not experience opioid withdrawal symptoms.

Methods: Here, we experienced a case in which a cancer patient without brain metastasis presented with anxiety and restlessness that was severe enough to interfere with daily life. The patient was diagnosed with naldemedine-induced opioid withdrawal syndrome.

Results: The patient was a 66-year-old male with liver cancer metastasizing to the chest wall, but without brain metastasis. Oxycodone was started at 10 mg/day 2 months prior to his visit to our department to treat pain related to the chest wall metastasis, and was increased to 100 mg/day 1 month later and maintained at that dose. Naldemedine was administered as a countermeasure against opioid-induced constipation. The patient developed anxiety and restlessness 10 days prior to his initial visit to our department. After detailed examination, naldemedine-related opiod withdrawal syndrome was suspected on the basis of anxiety, agitation, and episodes of sudden onset sweating, and these symptoms disappeared within 2 days after the discontinuation of naldemedine, with no recurrence observed thereafter. In addition, head MRI revealed no brain metastasis.

Significance of the results: Even in patients without brain metastasis, naldemedine can induce opioid withdrawal symptoms, so caution is required with patients receiving this drug. In addition, when psychiatric symptoms are pronounced, as in this case, withdrawal symptoms may be underdiagnosed.