Pyridoxal 5 phosphate for neuroleptic-induced tardive dyskinesia.

This was a systematic review/meta-analysis of 3 randomized placebo-controlled trials in adults with schizophrenia or schizoaffective disorder who had neuroleptic-induced tardive dyskinesia. All trials were conducted in inpatient psychiatric settings at Be’er Sheva Mental Health Centre in Israel, and the active vitamin B6 arms included 44 participants in total.

Vitamin B6, also referred to as pyridoxal 5 phosphate or pyridoxal phosphate, was tested as an add-on to ongoing antipsychotic treatment. Doses ranged from 400 mg daily to 600 mg twice daily (1200 mg/day), with treatment durations of about 4 to 12 weeks.

Vitamin B6 appeared to reduce tardive dyskinesia severity compared with placebo, but the evidence base was small and imprecise. The pooled global clinical efficacy result favored vitamin B6, with RR 19.97 (95% CI 2.87 to 139.19; n = 65 across 2 studies), and the pooled endpoint ESRS tardive dyskinesia score was lower by MD -4.07 (95% CI -6.36 to -1.79; n = 60 across 2 studies). Individual trials also showed lower endpoint ESRS scores with vitamin B6, including 2.3 (2.7) vs 8 (3.8) at week 4 and 4.7 (4.32) vs 7.4 (6.11) at week 12. Adverse events and discontinuation were uncommon but reported more often in the vitamin B6 group in one study, with 2/28 adverse events vs 0/22 and 5/28 discontinuations vs 0/22.

Overall certainty was low because only 3 small trials were available, follow-up was short, and trial design/reporting limitations were noted. Effect estimates were imprecise with very wide confidence intervals, one study had unusable endpoint ESRS data, and safety conclusions are limited by sparse adverse event reporting.