Antiparkinsonian agents and long-term neuroleptic treatment. Effect of G 31.406, orphenadrine, and placebo on parkinsonism, schizophrenic symptoms, depression and anxiety.

The need for medication with anticholinergic antiparkinsonian drugs was examined in 118 schizophrenic patients under long-term neuroleptic treatment. It was found that 1) none of 18 patients under treatment with low mg potency neuroleptics (chlorprothixene, clozapine, and thioridazine) had any need for anticholinergics; 2) of 60 patients under treatment with short-acting high mg potency neuroleptics (perphenazine greater than 16 mg daily and haloperidol greater than 2 mg daily) nine patients (15%) required medication with anticholinergics, whereas 3) of 40 patients under treatment with long-acting (depot) neuroleptics, 17 (43%) had a need for anticholinergic medication; and 4) no patient factors predisposing to the need for continued antiparkinsonian treatment could be identified. In an additional double-blind cross-over study of 12 patients presenting persisting neuroleptic-induced parkinsonism, it was found that G 31.406 (a new potentially antiparkinsonian drug), compared with placebo, had an antiparkinsonian effect (P less than 0.01) as well as an antidepressant effect (P less than 0.05). G 31.406 resulted in an improvement in anxiety and schizophrenia-score in some patients. Compared with placebo, orphenadrine had a more questionable effect on parkinsonism (0.05 less than P less than 0.01) and no significant effect on mental symptoms. There were no significant differences between the effects of G 31.406 and orphenadrine.