Determinants of Concentration/Dose Ratio and Weight Gain of Olanzapine in Teen Patients

doi:10.19803/j.1672-8629.20250484

Abstract

Abstract: Objective To investigate the contributors to the olanzapine concentration/dose (C/D) ratio and weight gain among teen patients by analyzing serum concentrations of olanzapine in order to provide a reference for rational use of olanzapine in teenagers. Methods Serum concentrations and associated clinical results of olanzapine were collected from the therapeutic drug monitoring (TDM) data of 270 inpatients treated with olanzapine at Shenzhen Kangning Hospital between 2020 and 2024. The effects of gender, body mass index (BMI) and comedications on olanzapine concentrations were analyzed while risk factors for weight gain were explored. Results Among the 270 teen patients, the ratio of males to females was 1∶1.57, and the average age was (15.5±1.3) years, the daily dose of olanzapine was 15.0 (5.0, 20.0) mg·d^-1, the serum concentration was 37.8 (23.9, 56.5) ng·mL^-1 and the C/D ratio was 3.33 (2.35, 4.43) ng·mL^-1·mg^-1. The C/D ratio of female patients was higher than that of male patients, with statistically significant differences (P<0.05). The C/D ratio of olanzapine in obese patients (BMI>24.0 kg·m^-2) was lower than that of normal patients (BMI 18.5 to 24.0 kg·m^-2),with statistically significant differences (P<0.05). The C/D ratio of patients treated with olanzapine combined with valproate was lower than that of patients who were not, with statistically significant differences (P<0.05). The C/D ratio of patients treated with olanzapine combined with fluoxetine was higher than that of patients who were not, with statistically significant differences (P<0.05). Wight gain was more prevalent in teenagers than in adults. Logistic regression analysis showed that BMI, C/D ratios and concomitant antidepressants were protective factors for weight gain. Conclusion Gender, BMI, and the combination of valproate and fluoxetine can impact the C/D ratio of olanzapine. In addition, BMI, C/D ratios and the combination of antidepressants are contributors to weight gain.

Key words: Olanzapine, Valproate, Fluoxetine, Therapeutic Drug Monitoring, Dose Corrected Concentration, Weight Gain

CLC Number:

R971
R994.11

PENG Chenchen, ZENG Huansi, ZHANG Moli. Determinants of Concentration/Dose Ratio and Weight Gain of Olanzapine in Teen Patients[J]. Chinese Journal of Pharmacovigilance, 2026, 23(4): 460-463.

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URL: https://zgywjj.magtechjournal.com/EN/10.19803/j.1672-8629.20250484

https://zgywjj.magtechjournal.com/EN/Y2026/V23/I4/460

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