Vol.72 No.1 January 2024
Rapid measurement of plasma voriconazole concentration by high performance liquid chromatography in the hospital: therapeutic drug monitoring and medical care support for outpatients
1)Department of Pharmacy, Sakai City Medical Center, 1-1-1 Ebaraji, Nisi-ku, Sakai city, Osaka, Japan
2)Pharmacy and Technical Division, Sakai City Medical Center
3)Department of Analytical & Bioinorganic Chemistry, Division of Analytical and Physical Sciences, Kyoto Pharmaceutical University
4)Department of Infectious Diseases, Sakai City Medical Center
Abstract
Therapeutic drug monitoring (TDM) by measurement of the plasma concentration is recommended in patients receiving treatment with voriconazole (VRCZ). In Japan, measurement of the plasma VRCZ concentration is covered by insurance for inpatients, but not for outpatients. Therefore, measurements of the plasma VRCZ concentration is often not performed in outpatients. We have established a high performance liquid chromatography (HPLC)-UV detection system for determining the plasma VRCZ concentration at our hospital, and use this method to measure the plasma VRCZ concentrations in outpatients. The turnaround time for this measurement is short and we are able to use the results to contribute to the clinical management of the patients. Herein, we report on the current status at our hospital.
Outpatients who underwent TDM by measurement of the plasma VRCZ concentrations and received pharmacists' support for medical management between October 2020 and May 2023 were included. The plasma VRCZ concentrations, indication for VRCZ administration, content of the pharmacists' proposal based on the drug concentration, presence/absence of hepatic impairment, visual impairment and acceptance of the proposal, etc., were comprehensively investigated.
Plasma VRCZ concentrations were measured in 6 outpatients during the above period, and the number of samples measured was 20, including 1 which was eventually excluded from the analysis, and 1 in which the concentration was below the limit of determination using the standard curve. The median (range) plasma concentration was 1.49 (0.54-5.00) μg/mL. There were 6 (31.6%) proposals to increase the dose and 1 (5.3%) proposal to decrease the dose from pharmacists. Additionally, in 16 cases (84.2%), the pharmacists' suggestions were made on the same day as that of the outpatient visit. The overall proposal acceptance rate was 94.1%.
The measured values were found to be outside the optimal concentration range (1.00 to 4.00 μg/mL) in 7 cases (36.8%), and in all of these cases, the pharmacists recommended change of dosage based on the results. Thus, monitoring of the plasma VRCZ concentrations is important even in outpatients. Additionally, by using our in-hospital HPLC system, in many cases, we were able to both make proposals on the same day as that of the outpatient visit and quickly reflect the results of the blood concentration measurement in the medical management of the patients at municipal hospitals. In the future, we will continue to attempt to build a measurement system that would allow the measurement to be made in a larger number of patients.
Key word
voriconazole, TDM, high performance liquid chromatography, outpatient
Received
August 4, 2023
Accepted
October 2, 2023
Jpn. J. Chemother. 72 (1): 9-16, 2024
