Topiramate in the Treatment of Neuropathic Pain in Patients with Cancer

IntroductionNeuropathic pain has been reported to affect 40%–50% of patients with cancer.Patients and MethodsConsecutive patients selected from the outpatient/adult patient palliative care clinic of the Roudebush Veterans Affairs Medical Center and the Indiana University Palliative Clinic were reviewed. A verbal pain linear analogue assessment scale was used to assess neuropathic pain. Pain medication history was also reviewed in addition to percent pain relief. The following variables were extracted from the medical record: pain characteristics, location, cause, date of initiation of therapy, maximal tolerated dose, pain scores on the visit of optimal tolerated dose, other concurrent medications, number of months of pain before initiation of topiramate therapy, and total duration of topiramate therapy. Decrease in worst, best, and average pain was recorded, as were the development of any adverse effects.ResultsOf the 13 patients on second- and third-line therapy, 53.8% had ≥ 30% decrease in worst pain; 69.2% had ≥ 30% decrease in average pain, and 53.8% had ≥ 30% decrease in best pain. Eight of 13 patients (61.5%) experienced adverse effects. Five patients discontinued (38.5%) topiramate because of adverse events.ConclusionBecause our retrospective study showed topiramate to be a beneficial second- and third-line therapy in patients with cancer who did not experience adequate pain control on previous regimens, further prospective studies are needed to establish this medication in the armamentarium of neuropathic cancer pain management.