Preliminary Determination of the Therapeutic Reference Range of Lurasidone in Chinese Patients and Analysis of the Factors Influencing Lurasidone Dose-Corrected Concentrations

BACKGROUND: The aim of this study was to determine the therapeutic reference range of lurasidone, and to analyze the factors influencing the dose-corrected concentration of lurasidone in Chinese psychiatric patients, thereby providing a basis for the development of individualized dosing of lurasidone. METHODS: A retrospective analysis was conducted for hospitalized patients who had received lurasidone and undergone blood concentration monitoring from May 2022 to September 2023 at the Affiliated Brain Hospital of Guangzhou Medical University. Analyses were based on patient demographic data, treatment regimens, and administered drug concentrations. RESULTS: Data for a total of 123 lurasidone steady-state trough concentrations were collected from 120 hospitalized patients. It was found that 85.56% of lurasidone steady-state trough concentrations were below the lower limit of the lurasidone therapeutic reference range (15 ng·mL -1 ), and that the median steady-state trough concentration was 7.09 ng·mL -1 (IQ1-IQ3 = 4.12-11.82 ng·mL -1 ). Gender, age, and co-medication with valproic acid were found to be significant factors influencing lurasidone steady-state trough concentration/daily dose (C/D) values. C/D values for females were 14% higher than those obtained for males. Among patients who did not receive concomitant administration of valproic acid, the C/D values were 55% higher than those who had received co-administered valproic acid. Furthermore, C/D values obtained for elderly patients (≥60 years) were 140% higher than those recorded for adolescents (<18 years) and 157% higher than those in younger adults (18-60 years). CONCLUSIONS: The findings of this study indicated that the guideline-recommended therapeutic reference range (15-40 ng·mL -1 ) for lurasidone may not be appropriate, at least for the Chinese population. More extensive therapeutic drug monitoring is recommended for elderly female patients and those receiving co-medication with lurasidone and valproic acid.