The Impact of Smoking, Sex, Infection, and Comedication Administration on Oral Olanzapine: A Population Pharmacokinetic Model in Chinese Psychiatric Patients.

This study included a total of 1546 serum olanzapine concentrations from 354 Chinese adult psychiatric patients that were analyzed by a complex mathematical model. The goal was to explore how oral olanzapine is eliminated from the body in Chinese psychiatric patients and how to personalize its dosing. Prior studies using similar complex mathematical models only studied the effects of sex and smoking on olanzapine elimination. This study also investigated the influence of co-occurrence of infection and comedications, including dangguilonghui tablets. This is a Chinese herbal medicine used to treat constipation, including constipation secondary to olanzapine treatment. Olanzapine elimination was increased by the following variables: 1.23-fold by male sex, 1.23-fold by smoking, 1.23-fold by comedication with valproate, 1.16-fold by sertraline, and 2.01-fold by dangguilonghui tablets. Olanzapine elimination was decreased by the following variables: 0.75-fold by co-occurrence of infection, 0.70-fold by fluvoxamine, and 0.78-fold by perphenazine. This study contributes to the improvement of oral olanzapine dosing personalization, but further studies are needed to verify the effects of infection and comedications, including valproate and dangguilonghui.