Among people with epilepsy, levetiracetam (LEV) can cause neuropsychiatric adverse events (NPAEs) that impact negatively on quality of life. It has been suggested that pyridoxine can ameliorate LEV-related NPAEs. We conducted a systematic review of studies on the use of pyridoxine supplementation to relieve NPAEs associated with LEV therapy.

The review was conducted according to Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines. Medline, EMBASE, Scholar, Cochrane-CENTRAL (2000-2019), and EThOS platform were searched for studies on the use of pyridoxine in patients with LEV-related NPAEs. Proportions of patients reported to benefit from pyridoxine supplementation were tabulated, and a random-effect model meta-analysis was conducted.

Eleven retrospective studies/case reports and one randomized prospective study, mostly including pediatric populations, were identified. Retrospective studies, which were rated as low quality due to failure to control for bias, reported an overall improvement of NPAEs after pyridoxine supplementation in 72.5% (108/149) of patients. The proportion of patients showing improvement in a pooled analysis of the four largest retrospective studies (n = 134) was 72.1% (95% confidence interval (CI) 47.1-88.3), although there was high heterogeneity across studies (I = 82%, p < 0.01). In the only prospective trial, patients randomized to pyridoxine supplementation were more likely to show relief from NPAEs than patients not receiving supplementation (p < 0.01), but outcomes might have been affected by assessment bias.

This systematic review suggests that pyridoxine might be of benefit in relieving LEV-related NPAEs. However, the quality of the evidence is poor, and better-designed prospective studies that include quantitative as well as qualitative data are needed to define the role of pyridoxine in the management of LEV-related NPAEs.