Background: To promote model-informed precision dosing (MIPD) for vancomycin (VCM), we developed statements for therapeutic drug monitoring (TDM). Methods: Ten clinical questions were selected. The committee conducted a systematic review and meta-analysis as well as clinical studies to establish recommendations for area under the concentration-time curve (AUC)-guided dosing. Results: AUC-guided dosing tended to more strongly decrease the risk of acute kidney injury (AKI) than trough-guided dosing, and a lower risk of treatment failure was demonstrated for higher AUC/minimum inhibitory concentration (MIC) ratios (cut-off of 400). Higher AUCs (cut-off of 600 μg·h/mL) significantly increased the risk of AKI. Although Bayesian estimation with two-point measurement was recommended, the trough concentration alone may be used in patients with mild infections in whom VCM was administered with q12h. To increase the concentration on days 1–2, the routine use of a loading dose is required. TDM on day 2 before steady state is reached should be considered to optimize the dose in patients with serious infections and a high risk of AKI. Conclusions: These VCM TDM guidelines provide recommendations based on MIPD to increase treatment response while preventing adverse effects.

Voriconazole, an antifungal drug, is metabolized by a cytochrome P450 isozyme. Increased adverse effects are observed in Asians because of the high rate of poor metabolizers. In this therapeutic drug monitoring (TDM) guideline, recommendations were made according to ethnic group. Five clinical questions were used. For the preparation of the guideline, the performance of TDM in multicenter studies was surveyed (study 1). We also conducted a systematic review and meta-analysis (study 2) to establish recommendations for non-Asians and Asians. In study 1, 401 patients were surveyed. A risk of supratherapeutic concentrations was found in Japanese patients who adhered to the recommended dose. Target trough levels were achieved in 87% of patients with dose reductions. Although the trough level measured at the onset of adverse effects (AEs) was significantly associated with hepatotoxicity, no significant correlation was found between the initial trough level and hepatotoxicity, which indicated that hepatotoxicity was successfully prevented by the trough-guided dosing. In study 2, 22 studies (11 Asian locations and 11 non-Asian locations) were included in meta-analysis for the relationship between trough cutoff level (3, 4, 5, 5.5, and 6 µg/mL) and AEs. Significant differences were found for all cutoff levels, with the highest odds ratio for 4.0 µg/mL in Asian locations. In contrast, in non-Asian locations, no more than 1 study was available for any trough cutoff level, except for 5.5 µg/mL, at which level a significant increase in AEs was found. These findings indicate that TDM is strongly recommended to prevent AEs in Asians, and TDM is generally recommended for non-Asians to address subtherapeutic concentrations. TDM on day 3 is recommended to assess pharmacokinetic properties, including loading and maintenance doses. If the patient condition permits, delaying until day 5 is suggested for Asians because of the prolonged t_½ in poor metabolizers. A trough level ≥1.0 µg/mL is strongly recommended to improve efficacy. Trough levels ≥2.0 µg/mL are suggested for invasive aspergillosis. To decrease adverse effects, trough levels <4.0 µg/mL are strongly recommended in Asians, whereas trough levels <5.5 µg/mL are generally recommended in non-Asians. Maintenance doses of 4 and 3 mg/kg twice daily are recommended in non-Asians and Asians, respectively. Different indications, timings, and target trough levels for TDM and different regimens are suggested for Asians and non-Asians.

This systematic review and meta-analysis examined the optimal trough concentration of voriconazole for adult patients with invasive fungal infections. We used stepwise cutoffs of 0.5–2.0 μg/mL for efficacy and 3.0–6.0 μg/mL for safety. Studies were included if they reported the rates of all-cause mortality and/or treatment success, hepatotoxicity, and nephrotoxicity according to the trough concentration. Twenty-five studies involving 2554 patients were included. The probability of mortality was significantly decreased using a cutoff of ≥1.0 μg/mL (odds ratio (OR) = 0.34, 95% confidence interval (CI) = 0.15–0.80). Cutoffs of 0.5 (OR = 3.48, 95% CI = 1.45–8.34) and 1.0 μg/mL (OR = 3.35, 95% CI = 1.52–7.38) also increased the treatment success rate. Concerning safety, significantly higher risks of hepatotoxicity and neurotoxicity were demonstrated at higher concentrations for all cutoffs, and the highest ORs were recorded at 4.0 μg/mL (OR = 7.39, 95% CI = 3.81–14.36; OR = 5.76, 95% CI 3.14–10.57, respectively). Although further high-quality trials are needed, our findings suggest that the proper trough concentration for increasing clinical success while minimizing toxicity is 1.0–4.0 μg/mL for adult patients receiving voriconazole therapy.

We aimed to assess the frequency of acute kidney injury (AKI) in different areas under the concentration–time curve (AUC) values of vancomycin (VAN) using a two-point blood collection method, allowing for accurate AUC assessment in critically ill patients. This multicenter retrospective observational study was conducted in eight hospitals. We retrospectively analyzed the data of patients who had received VAN in an intensive care unit (ICU) between January 2020 and December 2022. The primary outcome was the incidence of AKI. Patients were classified into three groups according to the AUC _24–48h at the initial therapeutic drug monitoring (TDM) as follows: <500, 500–600, and ≥600 µg·h/mL. The AUC _24–48h values were calculated using the Bayesian estimation software Practical AUC-guided TDM. Among 146 patients [median age (interquartile range), 67 (56–78) years; 39% women], the AUC _24–48h <500 µg·h/mL had an AKI rate of 6.5% (7/107), the AUC _24–48h 500–600 µg·h/mL had an AKI rate of 28.0% (7/25), and the AUC _24–48h ≥600 µg·h/mL had an AKI rate of 42.9% (6/14). In multivariate Cox proportional hazard analysis, the AUC _24–48h 500–600 µg·h/mL [hazard ratio 5.4, 95% confidence interval (CI) 1.64–17.63] and the AUC _24–48h ≥600 μg·h/mL (hazard ratio 7.0, 95% CI 2.31–21.18) significantly correlated with a higher incidence of AKI compared with the AUC _24-48h <500 μg·h/mL. In conclusion, we identified an association between AUC on day 2 and the risk of AKI in ICU patients, suggesting that not only AUCs above 600 µg·h/mL but also those between 500 and 600 µg·h/mL pose a risk for AKI. IMPORTANCE: Vancomycin (VAN) is a glycopeptide antibiotic and one of the most commonly used antibiotics for severe infections caused by methicillin-resistant Staphylococcus aureus . However, higher VAN concentrations have been associated with an increased risk of acute kidney injury (AKI). Herein, we aimed to assess the frequency of AKI in different areas under the concentration–time curve (AUC) values of VAN using a two-point blood collection method, allowing for accurate AUC assessment in critically ill patients. We identified an association between AUC on day 2 and the risk of AKI in intensive care unit patients, suggesting that not only AUCs above 600 µg·h/mL but also those between 500 and 600 µg·h/mL pose a risk for AKI. Therefore, individualized dosing is feasible, with pharmacists being able to optimize VAN doses to attain appropriate targets.