Age Impacts Olanzapine Exposure Differently During Use of Oral Versus Long-Acting Injectable Formulations: An...

Area of Science:

• Pharmacology
• Geriatric Medicine
• Psychiatry

Background:

• Olanzapine is a widely used antipsychotic, available in oral and long-acting injectable (LAI) forms.
• Limited data exist on olanzapine-LAI safety and efficacy in elderly populations.
• Age-related physiological changes can impact drug pharmacokinetics.

Purpose of the Study:

• To examine how increasing age affects olanzapine exposure.
• To compare olanzapine exposure between oral and LAI formulations in different age groups.
• To assess the suitability of olanzapine-LAI for older patients.

Main Methods:

• Observational study utilizing therapeutic drug monitoring data (2005-2017).
• Outcome variables included absolute olanzapine concentrations and concentration/dose ratios.
• Linear mixed-model analyses were employed to account for multiple samples per patient and covariates.

Main Results:

• Data from 8,288 patients (21,378 measurements) were analyzed.
• Dose-adjusted olanzapine concentration significantly increased with age for oral administration (P < 0.001).
• Increasing age did not affect olanzapine concentration following LAI administration (P = 0.550).

Conclusions:

• Systemic exposure of oral olanzapine increases with age.
• Systemic exposure of olanzapine-LAI is unaffected by age, likely due to minimal impact on absorption and metabolism.
• Olanzapine-LAI is pharmacokinetically suitable for older patients requiring long-term treatment.