Objectives: Thrombocytopenia (TP) is a common adverse effect of linezolid (LZD). However, risk factors for LZD-associated TP have been reported in Western patients with relatively heavy body weight. The aim of this study was to determine the risk factors for LZD-associated TP in Asian population.
Materials and methods: A retrospective cohort study was conducted among 101 consecutive patients who received LZD therapy (1,200 mg/day) between July 2003 and December 2013 at a tertiary referral hospital in Tokyo, Japan. The patients with obvious other causes for TP were excluded. The information of target infectious disease, patients' age, gender, body weight, body mass index, baseline serum creatinine (SCr), baseline platelet count, and treatment duration was collected retrospectively. TP was defined as ≥ 50% decrease in platelet count from baseline. Bi- and multi-variate analyses were performed.
Results: A total of 101 patients were included (mean age [SD] 64 [18]; male gender [%], 57 [56]). Median duration [range] of LZD therapy was 14 days [1-67]. LZD-associated TP was identified in 42 patients (42%). For TP, adjusted odds ratio (OR) [95% CI] of daily per kg dose (DPKD) and SCr was 1.14 [1.05-1.26] and 1.51 [1.01-2.50], respectively.
Conclusions: Higher DPKD and elevated SCr are significantly associated with LZD-associated TP. These findings suggest that daily dose of LZD should be adjusted using body weight, as typically done in pediatrics, in adults as well. Renal function also should be considered for dose adjustment.