Assessment of the therapeutic range of tiapride in patients with tardive dyskinesia.

Ten patients with tardive dyskinesia were treated with tiapride at an increasing dosage to establish the dose-concentration relationship and the dose-effect relationship. The effect was scored with the Abnormal Involuntary Movement Scale (AIMS) and the Doppler-radar method. The intra individual dosage-serum concentration correlation coefficients varied from 0.86 to 0.99 and the slopes of the individual regression lines varied from 0.16 to 0.58. All patients showed a diminution of their involuntary movements during the treatment period. A negative correlation coefficient was found between the dosage of tiapride and the AIMS; range -0.22 till -0.93, mean: -0.65 +/- 0.23 (SD). The Doppler-radar method results were inconclusive. No side-effects were observed.