RESUMEN
Optimal pain management in patients with advanced cancer often requires multiple pharmacological interventions and multimodal approach. Ketamine is an anaesthetic agent with increasing evidence supporting its use for pain. Due to its N-methyl-D-aspartate antagonism and its activity at opioid receptors, it is an adjuvant to traditional analgesics. Ketamine has a safety profile with limited experience of oral prolonged use in patients with cancer. We report a case of a 40-year-old man with refractory neuropathic cancer-related pain. Opioid rotation to methadone was previously performed, coanalgesics were added, the patient was reluctant to invasive anaesthetic techniques and his pain was poorly controlled. Ketamine was added to attenuate pain keeping functionality. This is a report of a patient with refractory cancer pain treated with methadone and ketamine orally during months, without reported side effects. Ketamine's use to treat pain is increasing along with its evidence of efficacy for long-term oral use.