Effects of lactational exposure of olanzapine and risperidone on hematology and lymphoid organs histopathology: A comparative study in mice neonates

Body weight gain, sexual/reproductive dysfunction and hematological abnormalities are serious consequences of atypical antipsychotics treatment. No attempts however have been made preclinically to elucidate the adverse hematological impacts. Presently, effects of lactational exposure of olanzapine (4,8 and 10 mg/kg) and risperidone (1 and 2 mg/kg) on hematology as well as lymphoid organ histopathology of mice neonates were investigated. Both olanzapine and risperidone transfers through milk and make the neonates susceptible to their adverse side effects. Corticosterone elevation tendency of both the drugs further enhance the susceptibility for immune dysfunction. Analysis of total and differential leukocytes counts revealed neutropenia with all the doses of olanzapine but only with risperidone 2 mg/kg. Weight analysis and histopathology of thymus and spleen indicated a state of suppression; less in the risperidone-exposed groups. Significant plasma corticosterone elevation occurred on 4 and 8 mg/kg olanzapine exposures but not with 10 mg/kg as well as with both the risperidone doses. Elevation of plasma prolactin levels occurred dose-dependently for both the drugs. Hematological toxicity (neutropenia) might be the direct toxic effects of the drugs/unstable metabolites on circulating neutrophils and/or on the bone marrow hemopoietic cells. Direct toxicity of the drugs might also have suppressed the lymphoid organs thymus and spleen. Further, it could be associated to hormonal imbalance induced by adverse pharmacological effects of the drugs on the endocrine system. Suppression of lymphoid organs in olanzapine groups might have resulted because of corticosteronemia and hyperprolactinemia, while in risperidone it could be mediated by pronounced hyperprolactinemic effect alone. (C) 2010 Elsevier B.V. All rights reserved.