Pharmacovigilance of drug-drug interactions: A pharmacokinetic study on the combined oral administration of lurasidone and clozapine in rats by using LC-MS/MS

In recent years, the expanding array of psychotropic medications has led to an increase in drug-drug interactions, particularly with combinations of different antipsychotics or psychotropic medications in clinical practice. However, the potential pharmacokinetic interactions between Lurasidone and Clozapine have not been extensively studied. Thus, this study aims to investigate these potential interactions by analyzing their pharmacokinetics in rat plasma after single oral administrations using developed LC-MS/MS methods. The study revealed notable changes in Lurasidone's pharmacokinetic parameters between single and combination administrations. Specifically, there were significant reductions in t_1/2 and V_d by 3.3 and 1.5-fold (p < 0.05) respectively, while C_max and AUC_0-t proved a significant increase by 1.8 and 1.6-fold (p < 0.05) respectively following the combination administration. Furthermore, separate co-administration markedly decreased Clozapine's C_max and AUC 0-t by 1.6 and 1.3-fold (p < 0.05) respectively, after the combination administration. Moreover, the AUC ratio for Lurasidone was 0.2, indicating a diminished therapeutic effect, whereas the AUC ratio for Clozapine suggested an elevated risk of adverse effects. These findings confirm the presence of drug-drug interactions between Lurasidone and Clozapine, suggesting potential implications for treatment efficacy. Recommendations for future clinical research include conducting pharmacodynamic studies to evaluate the impact of Lurasidone and Clozapine combination therapy. This underscores the importance of thoroughly assessing these interactions for clinical relevance and provides a scientific foundation for future evaluations of this drug combination.