Pregabalin for Opioid-resistant Neuropathic Pain in Bone Metastases

Background/Aim: To evaluate the tolerability and effectiveness of pregabalin for the treatment of opioid-resistant neuropathic pain associated with bone metastases in patients with cancer.

Patients and Methods: This single-center retrospective study reviewed medical records from Kindai University Hospital between 2015 and 2020. Pregabalin tolerability was evaluated based on treatment continuation and the occurrence of adverse events. Effectiveness in pain relief was assessed using changes in the numerical rating scale (NRS) over a 7-35-day observation period, which was specifically defined to exclude the effects of chemotherapy and radiotherapy.

Results: Among 26 patients with bone metastases who were newly prescribed pregabalin for neuropathic pain refractory to opioids in Group 1, six (23%) discontinued pregabalin because of adverse events, including dizziness and somnolence. All six patients were aged ≥60 years. The median age was higher in the discontinuation group than in the continuation group (74 vs. 61 years). Twelve patients who continued treatment (Group 2) were evaluated for effectiveness. A consistent reduction in NRS scores was observed in eight patients (67%) who continued treatment, with four patients (33%) achieving a 50% or greater reduction in neuropathic pain intensity. Although the maximum pregabalin dose ranged from 50 to 300 mg/day, pain relief was observed in 80% (four of five patients) even at low dosages (50-75 mg/day).

Conclusion: This exploratory study suggests pregabalin may mitigate opioid-resistant neuropathic pain in patients with bone metastases, often at relatively low dosages. However, approximately 20% of patients, particularly older individuals, were intolerant to the medication. Initiating treatment at a low dose may be important for improving tolerability in older patients with cancer.