Evaluating the optimal dose of teicoplanin with therapeutic drug monitoring: not too high for adverse event, not too low for treatment efficacy.

Therapeutic drug monitoring (TDM) of teicoplanin is aimed at minimizing the clinical impact of pharmacokinetic variability; however, its benefits are still being defined. We performed a retrospective study of teicoplanin TDM focusing on the dose-serum concentration relationship and clinical outcomes in a clinical setting. From January 2017 to December 2018, patients receiving teicoplanin ≥ 72 h with TDM were enrolled. Patients were divided into three groups: non-loading (NL) group, low-dose loading (LD) group (loading dose < 9 mg/kg), and high-dose loading (HD) group (≥ 9 mg/kg). Serum teicoplanin trough concentration (Cmin) and adverse events (AEs) were evaluated in each regimen. A subgroup of patients with bacteremia was analyzed to evaluate clinical efficacy. Among 65 patients, 12, 18, and 35 were grouped in NL, LD, and HD, respectively. Achievement rates of Cmin > 20 mg/L within 10 days were significantly different among the groups (25.0%, 38.9%, and 68.6% in the NL, LD, and HD groups, respectively; P = 0.014). Fourteen patients (21.5%) had AEs, and higher Cmin over 10 days (adjusted odds ratio 2.08 per every 20 mg/L increases, 95% CI 1.13-3.84, P = 0.019) and age ≥ 65 years (P = 0.009) were identified as independent risk factors. In the subgroup analysis, HD regimen (P = 0.050) and high mean Cmin over 10 days (P = 0.025) were significantly associated with treatment success. Although HL regimen could achieve Cmin targets and improve clinical outcome during teicoplanin treatment, high Cmin was associated with AEs during treatment. Routine TDM can be helpful to optimize teicoplanin administration.