Residual neuroleptic-induced parkinsonian symptoms in schizophrenia. A naturalistic study with orphenadrine

A naturalistic study was performed on 44 schizophrenic outpatients diagnosed according to DSM III-R and presenting neuroleptic-induced extrapyramidal side-effects. All patients had been treated continuously for the previous 10-12 weeks with haloperidol (HL) combined with orphenadrine (ORD). The dosages of HL and ORD remained unchanged for at least four weeks before the evaluations. All patients were assessed for depressive features (HRS-D), extrapyramidal (EPSE) and anticholinergic (ACS check list) side-effects. The plasma levels of ORD and its metabolite tofenacine (TOF) were determined by gas chromatography. There was a positive relationship between HRS-D and EPSE total scores, while there was a negative relationship between age and EPSE total scores. No relationship between the administered dose and plasma levels of ORD was found. The HL daily dose (mg/kg), ORD plasma levels and the TOF/ORD plasma level ratio seem to influence significantly the severity of residual extrapyramidal side-effects.