Abstract: There are 10 included trials (N = 261) published between 1973 and 2010; eight are new from the 2015 and 2017 update searches. Forty-eight studies are excluded. Participants were mostly chronically mentally ill inpatients in their 50s, and studies were primarily of short (2 to 6 weeks) duration. The overall risk of bias in these studies was unclear, mainly due to poor reporting of allocation concealment and generation of the sequence. Studies were also not clearly blinded and we are unsure if data are incomplete or selectively reported, or if other biases were operating. One small, three-arm trial found that both alpha-methyldopa (N = 20; RR 0.33, 95% CI 0.14 to 0.80; low-quality evidence) and reserpine (N = 20; RR 0.52 95% CI 0.29 to 0.96; low-quality evidence) may lead to a clinically important improvement in tardive dyskinesia symptoms compared with placebo after 2 weeks' treatment, but found no evidence of a difference between alpha-methyldopa and reserpine (N = 20; RR 0.60, 95% CI 0.19 to 1.86; very low quality evidence). Another small trial compared tetrabenazine and haloperidol after 18 weeks' treatment and found no evidence of a difference on clinically important improvement in tardive dyskinesia symptoms (N = 13; RR 0.93, 95% CI 0.45 to 1.95; very low quality evidence). No study reported on adverse events. For remaining outcomes there was no evidence of a difference between any of the interventions: alpha-methyldopa versus placebo for deterioration of tardive dyskinesia symptoms (1 RCT; N = 20; RR 0.33, 95% CI 0.02 to 7.32; very low quality evidence), celiprolol versus placebo for leaving the study early (1 RCT; N = 35; RR 5.28, 95% CI 0.27 to 102.58; very low quality evidence) and quality of life (1 RCT; N = 35; RR 0.87, 95% CI 0.68 to 1.12; very low quality evidence), alpha-methyldopa versus reserpine for deterioration of tardive dyskinesia symptoms (1 RCT; N = 20; not estimable, no reported events; very low quality evidence), reserpine or carbidopa/levodopa versus placebo for deterioration of tardive dyskinesia symptoms (2 RCTs; N = 37; RR 1.18, 95% CI 0.35 to 3.99; very low quality evidence), oxypertine versus placebo for deterioration of mental state (1 RCT; N = 42; RR 2.20, 95% CI 0.22 to 22.45; very low quality evidence), dopaminergic drugs (amantadine, bromocriptine, tiapride, oxypertine, carbidopa/levodopa) versus placebo for leaving the study early (6 RCTs; N = 163; RR 1.29, 95% CI 0.65 to 2.54; very low quality evidence), and tetrabenazine versus haloperidol for deterioration of tardive dyskinesia symptoms (1 RCT; N = 13; RR 1.17, 95% CI 0.09 to 14.92) and leaving the study early (1 RCT; N = 13; RR 0.23, 95% CI 0.01 to 4.00). Although there has been a large amount of research in this area, many studies were excluded due to inherent problems in the nature of their cross-over designs. Usually data are not reported before the cross-over and the nature of TD and its likely response to treatments make it imprudent to use this data. The review provides little usable information for service users or providers and more well-designed and well-reported studies are indicated.

Plain-language summary: . The review includes 10 small, short studies published mainly in the 1980s involving a total of 261 people. . One small study found that after 2 weeks' treatment both alpha-methyldopa and reserpine may lead to clinically important improvement in tardive dyskinesia symptoms compared with placebo, but the quality of evidence was low. We are uncertain about the effect of reserpine versus alpha-methyldopa; quality of evidence was very low. Another small trial compared tetrabenazine and haloperidol after 18 weeks' treatment, but again we are uncertain about the effect as the quality of evidence was very low. The included studies did not report on any harmful effects of the drugs. . Evidence is weak, limited, short term, and small scale. It is not possible to recommend these drugs as a treatment for tardive dyskinesia and their use is entirely experimental. There is a need for larger and more rigorous research in the area. This plain language summary was adapted by the review authors from a summary originally written by Ben Gray, Senior Peer Researcher, McPin Foundation (mcpin.org/).