Intranasal Ketamine for Episodic Neuropathic Pain in a Cancer Patient: A Case Report.

Abstract

Ketamine is an N-methyl-D-aspartate receptor antagonist traditionally used for dissociative sedation that has also been used for the treatment of pain. Ketamine can have a higher bioavailability when administered intranasally. To present a case in which intranasal (IN) ketamine was used for unpredictable, episodic, cancer-related neuropathic pain. We present a 49-year-old patient with metastatic adenocarcinoma of the lung who presented to our outpatient palliative care clinic with uncontrolled severe episodic neuropathic pain of the lower extremity. We prescribed compounded racemic ketamine 20-30 mg intranasally as needed at the onset of severe episodes of breakthrough pain, in addition to scheduled use of oral methadone and a buprenorphine patch for long-acting pain management. The patient reported a decrease in frequency, intensity, and duration of episodic breakthrough pain with use of IN ketamine without any reported negative adverse effects. Low-dose compounded racemic IN ketamine may be a useful and safe adjunct in alleviating severe breakthrough pain in cancer patients in the outpatient setting.