Iatrogenic Oral Ketamine Overdose in Palliative Care

Optimal pain management in the palliative care setting often requires multiple pharmacological interventions including novel and off-label therapies. Ketamine is an anesthetic agent with increasing evidence supporting its use for pain. Through N-methyl-d-aspartate antagonism and activity at opioid receptors, it is an adjuvant to traditional analgesics with the benefit of being opioid sparing. Ketamine has a wide safety profile with limited reports of overdose. Little is published on supratherpeutic dosing in the pain setting. We report a case of a 41-year-old male with refractory nociceptive and neuropathic cancer-related pain. Conventional therapies were ineffective. Ketamine was initiated to reduce opioid burden and attenuate pain with good response. The patient received an iatrogenic overdose (10 times ordered dose) of the drug. Several self-limited physiologic and psychologic reactions were observed during subsequent monitoring. This is a study and analysis of a patient with refractory nociceptive and neuropathic pain syndrome treated with ketamine who sustained an iatrogenic overdose of ketamine. Ketamine's use to treat pain is increasing along with its evidence of efficacy. Despite ketamine's wide safety profile, the medication is not without risk, especially in palliative care wherein patients are on multiple drugs with potentially severe interactions. Careful examination of the risks of overdose, especially of the various formulations of the drug, is needed.