The Role of Coadministration of Lidocaine and Ketamine in Opioid-Refractory Chronic Cancer-Related Pain.

Inclusion Criteria: * Age 18 years or more * Capacity to provide informed consent, ability to complete study assessments and comply with the study procedures * Meets the IASP definition for chronic cancer-related pain * Moderate or severe pain, defined as average pain of 4 or greater on an 11-point (0-10) NRS in the past 24h * Adequate trial of opioid medication, defined as a dose of at least 60 mg/day oral morphine equivalent or maximum tolerated dose, in the past 24h * For patients with neuropathic component to pain: adequate trial of at least one adjuvant analgesic, defined as a daily dose of at least Amitriptyline 37.5mg, Duloxetine 30mg, Gabapentin 900mg, Pregabalin 150mg, Venlafaxine 60mg or equivalent (26), or maximum tolerated dose in the past 24h Exclusion Criteria: * Previous adverse reaction to ketamine, lidocaine or other amide-type local anesthetics, midazolam * Severe liver disease (Child Class B or C) * SGPT or SGOT \>5 times the upper limit of normal * End stage kidney disease * Serious cardiac comorbidity (e.g. unstable angina, poorly controlled hypertension or tachycardia, high-risk coronary vascular disease, symptomatic heart failure with NYHA class III-IV, history of heart block, Wolf-Parkinson-White syndrome, Adams-Stokes syndrome) * Elevated intracranial or intraocular pressure * Pheochromocytoma or poorly controlled hyperthyroidism * History of psychosis, schizophrenia or substance abuse * Pregnant or breastfeeding * Porphyria * Life expectancy short…