178 Ketamine burst protocol: achieving pain control and opioid sparing in refractory neuropathic pain in cryoglobulinemia on a background of metastatic melanoma

<h3>Introduction</h3> Neuropathic pain in patients with metastatic melanoma and cryoglobulinemia poses a significant challenge in palliative care, often remaining refractory to opioid analgesics. Cryoglobulinemia, characterized by vasculitic neuropathy and ischemic tissue damage, exacerbates pain and reduces quality of life. Ketamine, an NMDA receptor antagonist, offers potential relief for opioid-resistant neuropathic pain, but its clinical application requires careful titration to balance efficacy with adverse effects. <h3>Methods</h3> A 58-year-old male with metastatic melanoma and cryoglobulinemia was admitted to a specialist palliative care unit for refractory neuropathic pain and lower limb ulcers. Despite high-dose opioids, pain persisted. A ketamine burst protocol was initiated, starting at 100 mg/day and titrated to 300 mg/day over five days. A second burst, limited to 200 mg/day to mitigate euphoria, followed. Transition to oral ketamine (20 mg TDS) was implemented for sustained relief. Pain control was assessed using the Symptom Assessment Scale (SAS) and Palliative Care Problem Severity Score (PCPSS). <h3>Results</h3> Ketamine infusion achieved significant pain reduction, enabling the patient to transition from chair-sleeping to lying comfortably in bed. The protocol reduced PRN opioid use from 7.8 mg to 1.3 mg of hydromorphone daily. Opioid infusion was lowered from 5 mg to 1.5 mg alfentanil, corresponding to a 73% reduction in morphine equivalence. Despite persistent ulcer progression, ketamine provided lasting pain relief and improved quality of life without major side effects. <h3>Conclusion</h3> Ketamine burst protocols effectively alleviate opioid-refractory neuropathic pain in complex palliative cases, promoting opioid-sparing and enhanced comfort. Individualized dosing and seamless transition to oral ketamine are crucial for sustained analgesia, underscoring the need for multimodal approaches in palliative neuropathic pain management.