Exacerbation of cancer pain after administering immune checkpoint inhibitor in a patient taking opioids: A case report.

WHAT IS KNOWN AND OBJECTIVE: Clinical cases of attenuation of opioid analgesic effect by administration of immune checkpoint inhibitors has not been reported. We present a case of head and neck cancer under pain management with opioids, in which cancer pain was exacerbated after administration of nivolumab. CASE SUMMARY: A male patient with head and neck cancer was hospitalized for the second-line treatment of nivolumab. He had complained of head and neck pain after admission, but the pain was especially worse after nivolumab administration. The dose of opioids was eventually increased by approximately 320% (morphine equivalent dose) compared to before administering nivolumab. WHAT IS NEW AND CONCLUSION: When administering immune checkpoint inhibitors such as nivolumab in clinical practice, the possibility of attenuation of opioid analgesic effect should be considered.