The Effects of Low Doses of Pregabalin on Morphine Analgesia in Advanced Cancer Patients

Abstract

Objectives: The aim of this study was to evaluate the opioid response in patients receiving morphine and pregabalin, independently from the presumed pain mechanisms, in comparison with patients receiving morphine treatment only.Methods: A multicenter prospective randomized controlled study was carried out in a sample of 70 advanced cancer patients with pain requiring strong opioids. Thirty-five patients (group MO) were randomized to receive sustained-release morphine using initial doses of 60 mg/day. Thirty-five patients (group MO-PR) were randomized to start the same morphine doses and pregabalin in increasing doses, starting with 25 mg/day up to 150 mg/day in one week. The following data were also recorded before starting the treatments (T0) and then at week intervals for four weeks (W1-4): age, gender, primary cancer and known metastases, pain causes and mechanisms, symptoms associated with opioid therapy, pain intensity, Brief Pain Inventory (BPI), morphine doses and escalation indexes (OEIs), and quality of life.Results: Forty-eight patients completed the study, twenty-eight and sixteen patients in group MO and MO-PR, respectively. Twenty patients were females, the mean age was 65.5 (±10.3), and the mean Karnofsky status was 66.0 (±18.9). No differences between groups were found in age (P = 0.839), Karnofsky status (P = 0.741), opioid doses as well as escalation indexes (OEI mg, P = 0.260, and OEI%, P = 0.270). No differences between the two groups were found in quality of life and all BPI items. Conclusion:The use of low doses of pregabalin added to morphine therapy in advanced cancer patients does not seem to provide advantageous analgesic effects, despite limitations of the present study due to the number of drop-outs.

Reviewing without a Clinical Background Is Detrimental for Cancer Pain Management

“…Is there a researcher that can reproduce data suggesting that pregabalin works as a sole analgesic in cancer patients, even with a neuropathic component? For instance, pregabalin added to morphine did not provide any substantial analgesic benefit [13]. More meaningful reviews regarding antiepileptic drugs, do not support such hypothesis, even when they are given on top of opioid therapy [14].…”

Pharmacological Treatment of Pain in Cancer Patients: The Role of Adjuvant Analgesics, a Systematic Review

“…Also, the mean percentage of change in pain was significantly greater in the pregabalin group: pregabalin: 46%, (95% CI: 40% to 53%); fentanyl: 22%, (95% CI: 15% to 30%), P < 0.001 . No significant differences were found in a study comparing morphine alone vs. a morphine–pregabalin combination in patients with advanced cancer, nor in a comparison with different doses of oxycodone–pregabalin combinations in non‐chemotherapy‐induced neuropathic pain …”

Randomized Study of Pregabalin in Patients with Cancer-Induced Bone Pain

“…Only a few published studies address pregabalin use in cancer-related pain and do not specifically target CIBP [25–29] and, with the exception of two trials [26, 28], these were open-label or observational studies. The results of one of the randomized controlled trials [26] suggested a morphine-sparing effect and improvement in neuropathic pain with pregabalin, whereas the other study suggested no analgesic benefit with the addition of pregabalin to morphine therapy [28]. Further well-conducted studies in this population would enable healthcare providers to make fully informed decisions regarding treatment.…”