Pharmacologic Treatment of Tardive Dyskinesia: A Meta-Analysis and Systematic Review.

OBJECTIVE: To examine the efficacy of pharmacologic treatments for tardive dyskinesia (TD). DATA SOURCES: PubMed was searched on December 12, 2017, for randomized, placebo-controlled trials examining the treatment of TD using the search terms (drug-induced dyskinesia OR tardive dyskinesia) AND (psychotic disorders OR schizophrenia). STUDY SELECTION: Studies were included if they examined tardive dyskinesia treatment as the primary outcome and were randomized and placebo-controlled trials. DATA EXTRACTION: The effect size (standard mean difference) of improvement (compared to placebo) stratified by medication class is reported for each of the trials included in this systematic review. A meta-analysis was conducted utilizing a fixed-effects model.
RESULTS: Vitamin E was associated with significantly greater reduction in TD symptoms compared to placebo (standardized mean difference [SMD] = 0.31 ± 0.08; 95% CI, 0.16 to 0.46; z = 4.1; P < .001). There was significant evidence of publication bias in vitamin E studies (Egger test: P = .02). Shorter duration of treatment and lower dose of vitamin E were significantly associated with greater measured treatment benefit. Vitamin B₆ was associated with significantly greater reduction in TD symptoms compared to placebo (SMD = 1.41 ± 0.22; 95% CI, 0.98 to 1.85; z = 6.4; P < .001) in 2 trials conducted by the same research group. Vesicular monoamine transporter 2 (VMAT2) inhibitors demonstrated significant benefit on tardive dyskinesia symptoms compared to placebo (SMD = 0.63 ± 0.11; 95% CI, 0.41 to 0.85; z = 5.58; P < .005). Amantadine was associated with significantly greater score reduction compared to placebo (SMD = 0.46 ± 0.21; 95% CI, 0.05 to 0.87; z = 2.20; P < .05). Calcium channel blockers were not associated with significantly greater score reduction compared to placebo (SMD = 0.31 ± 0.33; 95% CI, -0.34 to 0.96; z = 0.93; P = .35).
CONCLUSIONS: Data from multiple trials suggests that VMAT2 inhibitors, vitamin E, vitamin B₆, and amantadine may be effective for the treatment of TD. Evidence of publication bias and a significant negative association of dose and duration of treatment with measured efficacy suggest that the benefits of vitamin E in TD may be overstated. Head-to-head trials are needed to compare the efficacy and cost-effectiveness of pharmacologic agents for TD. © Copyright 2020 Physicians Postgraduate Press, Inc.