Amantadine versus biperiden: A double-blind study of treatment efficacy in neuroleptic extrapyramidal movement disorders

Anticholinergic treatment of neuroleptic extrapyramidal movement disorders (EPS) has been associated with induction of tardive dyskinesia. Also an increasing abuse of anticholinergics by schizophrenic patients is noted. Since as early as 1976, positive effects of amantadine (AMA) on neuroleptic EPS have been described, therefore a controlled study of these reports seemed worthwhile. Forty-two schizophrenic patients (of which 7 were dropouts) of three centers entered the study and were treated for EPS in a double-blind design: 18 (11 m, 7 f) with AMA and 17 (8 m, 9 f) with biperiden (BIP). Identical preparations of AMA (100 mg, tid) and BIP (2 mg, tid) were used in treatment of haloperidol-induced EPS (AMA, mean 22.4 mg haloperidol; BIP, mean 19.6 mg haloperidol). Effects of treatment and possible side effects were rated: EPS for the intensity of EPS, BPRS for quantification of psychotic symptoms, FSUCL for rating the side effects and KUSTA to document patients' mood. Ratings were recorded on days 0, 3, 7, 14, 28 and at discontinuation, respectively. All patients were treated with haloperidol and levomepromazine (for tranquilization/sleep induction) and the respective antiparkinsonian agent for 14 days. Patient characteristics did not differ significantly in either groups. In the AMA treatment group, 2 patients dropped out for noncompliance, in the BIP group, 5 (3 no effect, 1 noncompliance, 1 agitation). All results as recorded with the different rating instruments showed a significant (p < 0.01) overall improvement, whereas no significant differences between treatment groups could be determined, notably the treatment effect of both drugs on EPS was similar. Thus, the application of AMA in cases of neuroleptic EPS seems justified and is a useful alternative to anticholinergic drugs. Certain advantageous aspects of AMA treatment of EPS with regard to the glutamate hypothesis of schizophrenia and tardive dyskinesia are discussed.