Vitamins E, B6, VMAT2 inhibitors may reduce tardive dyskinesia symptoms
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Several pharmacologic treatments, including vitamin E, may reduce symptoms of tardive dyskinesia, or TD, according to results of a meta-analysis and systematic review published in Journal of Clinical Psychiatry.
“Antipsychotic medications were shown to be effective for psychotic disorders by randomized-controlled trials, meta-analysis and decades of clinical experience,” Bekir B. Artukoglu, MD, of Yale Child Study Center, told Healio Psychiatry. “These medications are also used to treat depression, mania and aggression. TD is a late-onset orofacial movement disorder that may develop after long-term antipsychotic treatment and cause medication nonadherence, disability and negative economic consequences. This meta-analysis examined the efficacy of different medications used to treat TD in randomized, placebo-controlled clinical trials..”
The investigators aimed to examine the efficacy of TD pharmacologic treatments by searching the PubMed database for randomized, placebo-controlled trials using the search terms drug-induced dyskinesia or tardive dyskinesia and psychotic disorders or schizophrenia. They included studies in which tardive dyskinesia treatment served as the primary outcome. For each of the trials included in the systematic review, they reported the standard mean difference (SMD) of improvement compared with placebo stratified by medication class, and they used a fixed-effects model for the meta-analysis.
Result showed an association between vitamin E and significantly greater reduction in TD symptoms compared with placebo (SMD = 0.31 ± 0.08; 95% CI, 0.16-0.46). However, they noted significant evidence of publication bias among vitamin E studies.
Shorter treatment duration and lower vitamin E dose were significantly associated with greater measured treatment benefit. Further, vitamin B6 was associated with significantly greater reduction in TD symptoms compared with placebo (SMD = 1.41 ± 0.22; 95% CI, 0.98-1.85) among two trials conducted by the same research group.
Vesicular monoamine transporter 2 inhibitors exhibited significant benefit for TD symptoms compared with placebo (SMD = 0.63 ± 0.11; 95% CI, 0.41-0.85). Moreover, amantadine demonstrated significantly greater score reduction compared with placebo (SMD = 0.46 ± 0.21; 95% CI, 0.05-0.87).
The researchers found no association between calcium channel blockers and significantly greater score reduction compared with placebo (SMD = 0.31 ± 0.33; 95% CI, 0.34 to 0.96).
“This meta-analysis indicates the importance of revising the clinical recommendations for TD in light of the strong evidence for the FDA-approved dopamine depleters,"Artukoglu told Healio Psychiatry. "The authors suggest large, head to head placebo-controlled trials comparing the efficacy and cost-effectiveness of FDA approved TD treatments and vitamins E and B6. This study also underlined the need to further investigate medications such as ginkgo biloba, clonazepam and amantadine.”