Clozapine in tardive dyskinesia: observations from human and animal model studies. Extrapyramidal reactions and amine metabolites in cerebrospinal fluid during haloperidol and clozapine treatment of schizophrenic patients. Failure of lithium treatment in established tardive dyskinesia. Anticholinergic challenge and neuroleptic withdrawal. Changes in dyskinesia and symptom measures. The effect of benzodiazepines on tardive dyskinesia symptoms. A single-blind, randomized trial comparing quetiapine and haloperidol in the treatment of tardive dyskinesia. A double blind trial of sulpiride in Huntington's disease and tardive dyskinesia. Treatment of tardive dyskinesia with galantamine: a randomized controlled crossover trial. Effect of baclofen on tardive dyskinesia.
Clozapine has long been considered a useful treatment in patients who have schizophrenia with the neuroleptic-induced delayed-onset side effect tardive dyskinesia. We present data in support of the clinical impression using both an animal model of the disorder and dyskinetic patients themselves. Clozapine produces a lower rate of oral dyskinesia in laboratory rats after 6 months of chronic treatment than does haloperidol (8.6 +/- 1.3 vs. 13.6 +/- 1.4 vacuous chewing movements every 5 minutes, respectively), suggesting a lower propensity to cause tardive dyskinesia. In the human, when clozapine was compared with haloperidol in the treatment of patients with tardive dyskinesia, clozapine produced significantly greater benefit for motor symptoms after 12 months of treatment than did haloperidol (p < .001). Moreover, the dyskinesia rebound, which occurred equally in both drug groups at the beginning of the study, was sustained in the haloperidol group but lost in the clozapine-treated patients. These data suggest that dyskinetic patients lose their symptoms of tardive dyskinesia, along with dopaminergic hypersensitivity, with long-term clozapine treatment. 8 male schizophrenic patients participated in a double-blind, cross over study of the extrapyramidal side-effects of haloperidol and clozapine (acute dystonis, Parkinsonism and tardive dyskinesia), together with their effect on homovanillic acid (HVA) and 5-hydroxyindoleacetic acid (5-HIAA) in the cerebrospinal fluid (CSF). Haloperidol (9 mg/day) caused Parkinsonism, reduced tardive dyskinesias and increased the HVA concentration in the CSF. Clozapine (225 mg/day) had no effect on the neurological phenomena but reduced HVA and 5-HIAA concentrations in the CSF. During the discontinuation phase following the administration of haloperidol, tardive dyskinesia occurred or was aggravated; this did not occur after administration of clozapine. Accordingly, it is suggested that clozapine does not induce dopaminergic hypersensibility and, therefore, will not induce tardive dyskinesias. Eleven patients with tardive dyskinesia were treated with lithium carbonate in a placebo-controlled double-blind crossover study. No significant effect of lithium on either tardive dyskinesia or blood prolactin concentrations was demonstrated, but 5 patients developed pseudo-Parkinsonian features. Benztropine mesylate (intravenous [IV] and oral) challenge was compared with brief neuroleptic withdrawal on dyskinesia ratings and symptom measures. Thirty-six neuroleptic-treated patients underwent a placebo-controlled acute IV challenge with 2 mg benztropine and a placebo-controlled two-week trial of oral benztropine mesylate (2 mg three times a day), followed by a double-blind placebo-controlled neuroleptic withdrawal involving four weeks of dose tapering and six weeks of placebo treatment. Benztropine given IV had no significant effect. Orally administered benztropine, however, led to statistically significant increases in dyskinesia and dysphoric mood. The brief neuroleptic withdrawal significantly increased dyskinesia scores and dysphoria and resulted in early termination of therapy in 12 of 36 patients (33%) due to symptom exacerbation. There was a striking absence of correlation between dyskinesia change measures brought about by benztropine and changes following neuroleptic withdrawal. Therefore anticholinergic challenge does not appear to be a fruitful procedure for identifying patients with covert dyskinesia. nan While the atypical antipsychotics should ultimately reduce the prevalence of tardive dyskinesia, it is likely to remain a significant clinical problem for a long time to come. No strategy has clearly emerged as the treatment of choice for tardive dyskinesia. Atypical antipsychotics have reduced propensities for producing acute extrapyramidal symptoms (EPS) and possibly tardive dyskinesia and may be effective in treating patients with established tardive dyskinesia.
                This 12-month, randomized, investigator-blinded study compared the efficacy of quetiapine (N = 22) and haloperidol (N = 23) in treating patients with DSM-IV schizophrenia or schizoaffective disorder and established tardive dyskinesia. Dyskinesia was assessed using the Extrapyramidal Symptom Rating Scale (ESRS) dyskinesia subscale scores and the Clinical Global Impression (CGI) dyskinesia scores. Other EPS, weight, serum prolactin level, and glycosylated hemoglobin level were also assessed. Subjects were enrolled in the study between April 2000 and March 2002.
                Mean endpoint doses were 400 mg/day of quetiapine and 8.5 mg/day of haloperidol. Compared with the haloperidol group, the quetiapine group showed significantly greater improvements in ESRS dyskinesia (6 and 9 months [p <or=.01]) and CGI dyskinesia (from 6 months onward [p <.05] and with repeated-measures analysis [p =.002]). Response rate (>or= 50% symptom reduction) was greater with quetiapine than haloperidol (64% [9/14] and 37% [6/16] at 6 months; 55% [6/11] and 28% [4/14] at 12 months). Other EPS decreased significantly with quetiapine at 3 (p =.01), 6 (p =.01), and 9 (p =.002) months. Serum prolactin levels decreased with quetiapine but increased with haloperidol, differing significantly between the groups at endpoint (p =.005). No significant changes in weight or glucose metabolism were recorded in either group.
                Quetiapine effectively reduces the severity of tardive dyskinesia and is well tolerated in patients with established tardive dyskinesia. Eleven patients with Huntington's disease and nine patients with tardive dyskinesia participated in a randomised double-blind crossover trial of sulpiride (as sole antidopaminergic therapy) versus placebo. Although functional improvement was not seen in Huntington's disease patients, sulpiride reduced movement count and total dyskinesia score in both conditions. Sulpiride differs pharmacologically in several respects from conventional neuroleptics, and has not been convincingly shown to cause tardive dyskinesia. Among currently available treatments, it may therefore be considered a drug of choice for treatment of tardive dyskinesia. Recent evidence suggests that tar-dive dyskinesia may result from antipsychotic-induced damage to striatal cholinergic neurons. To test whether cholinesterase inhibitors compensate for diminished cholinergic activity, we conducted a 30-week randomized, double-blind, placebo-controlled crossover trial of galantamine in patients with tardive dyskinesia.
                Patients with tardive dyskinesia were recruited between June 2001 and June 2004. After a 2-week baseline period, 35 male schizophrenia patients, on stable doses of antipsychotics, were randomly assigned to receive galantamine (8-24 mg) or placebo for two 12-week phases separated by a 4-week washout period. Patients were evaluated every 2 weeks for changes in extrapyramidal symptoms and before and after each treatment for effects on psychiatric symptoms and cognition.
                Galantamine reduced mean total Abnormal Involuntary Movement Scale (AIMS) scores more than placebo, but this difference was not statistically significant (p = .08). However, patients initially randomly assigned to galantamine showed a reversal of AIMS scores after switching to placebo. Simpson-Angus Scale ratings of parkinsonism were significantly higher with galantamine than placebo (p = .0005) and correlated with age. There were no significant differences between groups in akathisia, cognition, or psychiatric symptoms. More patients dropped out while receiving galantamine, but this outcome did not significantly influence the results.
                In contrast to previous reports, reductions in tardive dyskinesia associated with galantamine were not statistically significant compared with placebo in this trial. However, galantamine was associated with a modest rebound in dyskinesia scores after discontinuation and clinically minor but statistically higher ratings of parkinsonism. These findings support the need for further investigations of cholinergic mechanisms underlying tardive dyskinesia and extrapyramidal effects of cholinesterase inhibitors when used in combination with antipsychotics in susceptible patients.
                ClinicalTrials.gov identifier NCT00164242. Eighteen chronic psychiatric patients with neuroleptic-induced tardive dyskinesia of 1/2-9 years duration participated in a double-blind crossover study on the effect and side effects of baclofen and placebo in the treatment of tardive dyskinesia. Each treatment phase lasted 3 weeks. Evaluation of the results included an assessment of video-tape recording. Baclofen (20-120 mg daily) reduced the hyperkinesias (median score from 5 to 3, P less than 0.05) and increased the parkinsonism (median score from 5 to 7, P less than 0.01). The effect on the oral movement pattern of tardive dyskinesia was characterized by a reduced frequency, an unchanged or slightly reduced amplitude, and an increased duration of each separate mouth opening and tongue protrusion, a response pattern very similar to the response pattern of alpha-methyl-p-tyrosine, an inhibitor of the catecholamine synthesis. Sediation, muscular weakness, and confusion were observed in 50% of the patients. These side effects, appearing mainly in elderly patients, sometimes set in before the anti-hyperkinetic effect, thus limiting the practical usefulness of baclofen in the treatment of tardive dyskinesia.
One small study reports some preliminary evidence that benzodiazepines may have some effect in neuroleptic induced tardive dyskinesia. Inconclusive results from other studies means routine clinical use is not indicated and these treatments remain experimental.