Subject(s)
Antimanic Agents/pharmacology , Antipsychotic Agents/pharmacokinetics , Lithium Compounds/pharmacology , Sulpiride/analogs & derivatives , Adult , Amisulpride , Antimanic Agents/administration & dosage , Antimanic Agents/therapeutic use , Antipsychotic Agents/administration & dosage , Antipsychotic Agents/therapeutic use , Borderline Personality Disorder/drug therapy , Chromatography, High Pressure Liquid , Dose-Response Relationship, Drug , Drug Interactions , Drug Monitoring , Drug Therapy, Combination , Female , Humans , Lithium Compounds/administration & dosage , Lithium Compounds/therapeutic use , Longitudinal Studies , Male , Middle Aged , Schizophrenia/drug therapy , Sulpiride/administration & dosage , Sulpiride/pharmacokinetics , Sulpiride/therapeutic useABSTRACT
Up to now direct toxic effects or immunological processes have been said to explain clozapine-induced agranulocytosis. However, more recent studies may suggest that not yet metabolized clozapine is taken up by leukocytes and transformed by oxidative processes to apoptosis-inducing metabolites. To verify this hypothesis the concentrations of clozapine were measured in the plasma and the leukocytes of a patient receiving clozapine who developed clozapine-induced leukocytopenia and in 10 patients receiving clozapine who did not show any serious adverse side effects. The patient who developed leukocytopenia showed clozapine concentrations in the leukocytes that were about 8 times higher than the mean clozapine concentrations in the leukocytes in the group of 10 patients receiving clozapine with no changes in the leukocyte count in the history. However, no major difference was found in the clozapine plasma concentrations. The results may suggest that patients at risk of developing clozapine-induced leukocytopenia show increased clozapine concentrations in the leukocytes although the clozapine plasma concentration is in the therapeutic range. It is assumed that changes or abnormalities of clozapine uptake at the cell membrane might play a role in the development of clozapine-induced leukocytopenia and/or agranulocytosis.