Objective: To describe and understand the underlying mechanisms of a rapid remission of severe tardive dyskinesia and tardive dystonia in a 62 year old patient with a schizo-affective illness using the atypical antipsychotic substance quetiapine, a dibenzothiazepin-derivative.
Design: a single inpatient case study (n=1)
Materials and Methods: The ‘Abnormal Involuntary Movement Scale’(AIMS) was used before starting with quetiapine, and at three weeks, six month, one year and 18 months after starting with this atypical antipsychotic substance in order to evaluate the evolution of tardive dyskinesia and tardive dystonia in this patient. A literature search using Medline and the Cochrane Library (1995-2002) was performed using the search terms ‘tardive dyskinesia’ and ‘quetiapine’.
Results: This 62-year old lady, who had been treated for more than ten years with zuclopenthixol, a thioxanthene (conventional) antipsychotic substance, had developed moderate to severe tardive dyskinesia and dystonia (AIMS-score 9). Therefore she was switched from zuclopenthixol (10mg/day) to quetiapine (200mg/day). However, following a dosis reduction of zuclopenthixol to 6mg/ day she developped severe rigidity, tardive dyskinesia and dystonia (AIMS-score 34). Increase of the zuclopenthixol dosage to the initial dosage of 10mg resulted in a moderate improvement of the movement disorder (AIMS-score 17). After 4 weeks administering quetiapine, we observed a remission of these symptoms (AIMS-score 3). This remission remained up to one and a half years after starting with quetiapine. There are very rare cases indicating the effectiveness of quetiapine in the treatment of tardive dyskinesia in the elderly.
Conclusion: Severe tardive dyskinesia and tardive dystonia represent serious and potentially disabling movement disorders. Although many treatments have been tried, none have proven completely efficacious. The best treatment for tardive dyskinesia and dystonia is prevention, which is a function of medication choice. Pharmacologic interventions for tardive dyskinesia include clozapine and the other atypical antipsychotics. There is emerging literature in support of atypical antipsychotics for the treatment of existing drug-induced movement disorders, yet relatively little is known about its potential underlying mechanism. We report an elderly lady who demonstrated a rapid remission of tardive dyskinesia and tardive dystonia following treatment with quetiapine. Quetiapine may be useful as a therapeutic agent in the treatment of tardive dyskinesia. Further systematic research is needed. Plausible hypotheses of underlying mechanisms will be described.
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