A peripherally acting μ-opioid receptor antagonist for treating opioid-associated tinnitus: A case report.

[BACKGROUND] The use of opioids occasionally causes tinnitus. However, there is a paucity of data regarding the use of peripherally acting μ-opioid receptor antagonists for opioid-associated tinnitus in patients with cancer.

[ACTUAL CASE] A 74-year-old male with pancreatic cancer complained of abdominal pain. Two days after initiating oxycodone therapy, the patient experienced tinnitus during body movements. Although peripheral tinnitus disappeared after discontinuing oxycodone, it reappeared with hydromorphone or tapentadol administration.

[POSSIBLE COURSES OF ACTION] Drug cessation is a preferred intervention for drug-induced tinnitus; however, the cessation of opioids may not be feasible in patients with cancer who are already taking opioids.

[FORMULATION OF A PLAN] Based on the presumed mechanism of peripheral tinnitus, the use of peripherally acting μ-opioid receptor antagonists was planned, and 200 μg/day of naldemedine was prescribed for tinnitus relief.

[OUTCOME] Tinnitus disappeared immediately after initiating naldemedine, and the pain was well-controlled. The effect was preserved after increasing or switching opioids.

[LESSONS] The use of peripherally acting μ-opioid receptor antagonists may be an option to treat opioid-associated tinnitus without compromising the analgesic effects.

[VIEW] Further clinical data regarding the secondary effect of peripherally acting μ-opioid receptor antagonists on opioid-associated complications other than constipation are required.