We aimed to analyse the effects of age and sex on pain and cost for patients with chronic peripheral neuropathic pain (PNP) who have started treatment with brand name gabapentin versus generic gabapentin (EFG). We conducted a retrospective multicentre study using electronic medical records (EMR) for patients of both sexes, older than 18, who began treatment with brand name or generic gabapentin. Adherence (medication possession ratio MPR), persistence, use of healthcare resources, cost, and pain reduction were measured for one year. We analysed 1369 EMRs 61.1% women; mean age 64.6 (15.9), 52.4%≥65 years; 400 used brand name drugs while 969 used generic gabapentin. Persistence and adherence were higher in patients using brand name gabapentin (7.3 vs 6.3 months, P<.001; 86.5% vs 81.3% MPR, P<.001). Lower healthcare costs were observed in patients using brand-name gabapentin in both age groups (<65 and ≥65). Mean difference in cost per patient amounted to €221 (95%CI: 59-382) and €217 (95%CI: 51-382) in the <65 and ≥65 age groups, respectively (P<.01). Mean difference in cost among men amounted to €197 (63-328), while mean difference in cost among women amounted to €239 (96-397) (P=.005 and P=.004, respectively). Compared with EFG, brand treatment showed greater pain relief: 13.5% (10.9-16.2) and 10.8% (8.2-13.5) in <65 and ≥65year patients, respectively (P<.001), and 10.7% (8.2-13.2) and 13.8% (11.0-16.5) in women and men respectively (P<.001). Regardless of sex and age, patients who started PNP treatment with brand name medication showed greater persistence and adherence to treatment than those taking generic drugs. Brand name treatment also involved lower healthcare costs, and greater pain relief.