Human Hemoglobin and Antipsychotics Clozapine, Ziprasidone and Sertindole: Friends or Foes?

Packed with hemoglobin, an essential protein for oxygen transport, human erythrocytes are a suitable model system for testing the pleiotropic effects of lipophilic drugs. Our study investigated the interaction between antipsychotic drugs clozapine, ziprasidone, sertindole, and human hemoglobin under simulated physiological conditions. Analysis of protein fluorescence quenching at different temperatures and data obtained from the van't Hoff diagram and molecular docking indicate that the interactions are static and that the tetrameric human hemoglobin has one binding site for all drugs in the central cavity near αß interfaces and is dominantly mediated through hydrophobic forces. The association constants were lower-moderate strength (~104 M-1), the highest observed for clozapine (2.2 × 104 M-1 at 25 °C). The clozapine binding showed "friendly" effects: increased α-helical content, a higher melting point, and protein protection from free radical-mediated oxidation. On the other hand, bound ziprasidone and sertindole had a slightly pro-oxidative effect, increasing ferrihemoglobin content, a possible "foe". Since the interaction of proteins with drugs plays a vital role in their pharmacokinetic and pharmacodynamic properties, the physiological significance of the obtained findings is briefly discussed.

Effects of several atypical antipsychotics closapine, sertindole or ziprasidone on hepatic antioxidant enzymes: Possible role in drug-induced liver dysfunction.

Chronic use of atypical antipsychotics may produce hepatic damage. Atypical antipsychotics, including clozapine, sertindole, and ziprasidone, are extensively metabolized by the liver and this process generates toxic-free radical metabolic intermediates which may contribute to liver damage. The aim of this study was to investigate whether clozapine, sertindole, or ziprasidone affected hepatic antioxidant defense enzymes which consequently led to disturbed redox homeostasis. The expression and activity of antioxidant enzymes superoxide dismutase (SOD), glutathione peroxidase (GPx), glutathione reductase (GR), catalase (CAT), and glutathione-S-transferases (GST) were measured in rat livers at doses corresponding to human antipsychotic therapy. Clozapine increased activity of SOD types 1 and 2, GR and GST, but reduced CAT activity. Sertindole elevated activities of both SODs. In ziprasidone-treated rats only decreased CAT activity was found. All three antipsychotics produced mild-to-moderate hepatic histopathological changes categorized as regenerative alterations. No apparent signs of immune cell infiltration, microvesicular or macrovesicular fatty change, or hepatocytes in mitosis were observed. In conclusion, a 4-week long daily treatment with clozapine, sertindole, or ziprasidone altered hepatic antioxidant enzyme activities and induced histopathological changes in liver. The most severe alterations were noted in clozapine-treated rats. Data indicate that redox disturbances may contribute to liver dysfunction after long-term atypical antipsychotic drug treatment.

A Case Report of Exacerbation of Leg Ulcers Associated with Acute High-dose Acetylsalicylic Acid in a Patient with Klinefelter Syndrome.

Klinefelter syndrome (KS) is the most frequent type of congenital sex-chromosomal disorder caused by at least one extra X chromosome and commonly treated with lifetime testosterone therapy. Ulcerative lesions on lower extremities may occur as a complication of KS. The pathogenesis of ulcers in KS patients has not been clarified on a molecular level. Here we present a case of leg ulcers exacerbation associated with the administration of a high dose of acetylsalicylic acid in a 63-year-old KS patient with karyotype 47,XXY undergoing testosterone replacement therapy for the last 20 years. The appearance of the ulcer on the patient's leg occurred during one week of high oral acetylsalicylic acid intake (1.2 g daily). The patient was advised to return to his standard daily dose of 0.1 g of acetylsalicylic acid and significant improvement of his leg ulcer was observed after two weeks. We hypothesize that testosterone-mediated nitric oxide balance in KS patient is perturbed under the condition of acute high-dose acetylsalicylic acid administration. We propose that small standard doses of approximately 0.1 g/day of acetylsalicylic acid have no apparent effect on nitric oxide status, whereas higher doses may cause dysregulation of nitric oxide production and/or utilization, creating conditions which may cause the appearance of leg ulcers in the KS patients.