Abstract
Ketamine infusion therapy is increasingly being used as an effective treatment for chronic pain syndromes, including central sensitisation syndrome (CSS) or nociplastic pain. On the contrary, chemotherapy-induced peripheral neuropathy (CIPN) is a common but poorly understood condition arising secondary to cancer treatment complications, which poses significant challenges in its management due to limited therapeutic options. We present a case of a man in his 60s with chronic CIPN, later complicated by CSS and post-COVID-19 symptoms treated with a multiday subanaesthetic ketamine infusion, resulting in a clinically significant and sustained long-term improvement in function and pain control, for pain due to CSS and CIPN.This case highlights the use of multiday ketamine infusion therapy for the management of CSS and post-COVID-19 symptoms in a patient with well-documented severe treatment refractory CIPN. It demonstrates the growing evidence for ketamine as an analgesic agent for chronic pain, with potential considerations to expand its use for other indications. His response to ketamine infusion may implicate the possibility of a unifying mechanism in patients with nociplastic pain or CSS, post- COVID-19 symptoms and chronic CIPN.