OBJECTIVES: This study aimed to compare the cost-effectiveness of gabapentin combined with an opioid versus gabapentin monotherapy for the management of neuropathic cancer pain. METHODS: Randomized controlled trial aimed to compare monotherapy versus combined therapy to control neuropathic pain, in a subset of cancer/HIV-AIDS/Chemotherapy/PHN/DN patients. Patients were randomized to one of the following treatment protocols: 1) gabapentin and opioid combination (GO group), and 2) Gabapentin monotherapy (GG group) both groups are titrated according to pain response. Changes in pain intensity, DN-4, patient satisfaction and analgesic drug consumption were evaluated at 0, 7, 30, 60 and 90 days. Side effects were also recorded. We carried out an interim analysis in order to keep recruit patients for the entire protocol.  RESULTS: Fifty-four patients diagnosed with neuropathic pain were included. Forty-nine patients completed the study. These data suggest that GO treatment provides better relief of neuropathic pain in cancer patients compared with monotherapy. Besides, the GO treatment is a very-high cost-effectiveness alternative, cause in countries like Mexico the threshold falls below 1 GDP per capita. CONCLUSIONS: Our preliminary clinical observation shows that the addition of gabapentin to an opioid analgesic (tramadol + gabapentin) is safe with fewer side effects and demonstrate greater effectiveness at lower cost compared with gabapentin as monotherapy. Resulting in greater satisfaction and better adherence to treatment.