Toxic interaction between risperidone and clozapine: A case report

Although atypical antipsychotics have generally a decreased risk of neurotoxicity, there are reports regarding various neurotoxic or idiosyncratic reactions including neuroleptic malignant syndrome (NMS). The authors present here the toxic interaction between risperidone (RIS) and clozapine (CLZ) in a first-episode schizophrenic patient. A 20-year-old man suffering from first-episode schizophrenia - catatonic subtype, developed a neurotoxic syndrome, which has been characterized as a mild form of NMS, after CLZ (100 mg/day) was added to a regimen of RIS (16 mg/day). The NMS symptomatology subsided only by drug discontinuation and supportive care. Later, CLZ monotherapy restarted without further complications. This case report shows that neurotoxic syndromes, even NMS, may occur during combination therapy with RIS and CLZ. (C) 2001 Elsevier Science Inc. All rights reserved.