Prevalence and clinical outcomes of off‐label gabapentin prescription in neuropathic orofacial pain

Abstract

AbstractObjectivesThis study aimed to assess the prevalence, purposes, and clinical outcomes of off‐label gabapentin prescriptions, and to identify potential risks of gabapentin misuse.MethodsA retrospective cohort study was conducted from January 2014 to December 2022 at a single‐referral dental hospital. The study reviewed demographic data, clinical information, outcomes, side effects, and co‐prescribed drugs, utilizing statistical analyses to address objectives.ResultsAmong 1365 patients, 87 received gabapentin, representing about 6.37% of off‐label prescriptions. Trigeminal neuralgia (TN) was the most common indication (52.87%), often chosen as the clinician's first choice (51.72%), followed by use as an interim medication pending HLA‐B*15:02 results (14.94%). Nortriptyline was frequently co‐prescribed. Overall, gabapentin was prescribed at a mean dosage of 726.44 ± 42.87 (SE) mg per day, with a common dose range of 300–900 mg/day. Patients with TN and other neuropathies/facial pain experienced significant pain reduction from baseline (mean difference = −4.73 ± 0.77, p < 0.0001, and −3.06 ± 0.91, p = 0.0036, respectively). However, only 5 patients achieved a full response (NRS = 0) to gabapentin. Six patients (0.44%; 6 out of 1365 patients) received off‐label gabapentin without clinical diagnosis or treatment records, possibly indicating misuse.ConclusionsOff‐label gabapentin use was prevalent, especially in cases of TN. Despite significant pain reduction observed, only a small number of patients achieved pain‐free periods with their neuropathic pain condition. Therefore, optimal dosing is advisable. Off‐label gabapentin use also benefits patients as an interim medication while waiting for carbamazepine‐related gene screening in the Thai population and as a main drug therapy for HLA‐B*15:02 gene‐positive patients. Given the high prevalence of off‐label use and its potential to interact and enhance centrally mediated effects with other drugs, pre‐screening could aid in identifying potential risks of misuse and abuse.