Fever development in neuroleptic malignant syndrome during treatment with olanzapine and clozapine

Neuroleptic malignant syndrome (NMS) is the most dangerous life-threatening complication of antipsychotic medication. It's development is connected with the blockade of dopaminergic transmission (D2 receptors) in the nigrostriatal system of the brain. Fever is one of the main symptoms of this syndrome and it's elevation is due to the activation of the immune system. Numerous studies report that treatment with clozapine (doses 37.5–600 mg) or olanzapine (doses 10–25 mg) or the use of these drugs in polytherapy cause pyrexia between 37.8–40.6°C. Additionally, levels of proinflammatory interleukins such as IL-6, IL-1,TNF-α were increased. The aim of this article is to describe how olanzapine and clozapine influence fever development in NMS, in relation to the dose of the drug taken by schizophrenic patients including changes in immunological system.