High frequency of linezolid-associated thrombocytopenia among patients with renal insufficiency

This retrospective case–control study compared the tolerability and efficacy of linezolid between patients with and without renal insufficiency (serum creatinine ≥1.3 mg/dL for women and ≥1.5 mg/dL for men). All patients with Gram-positive infections treated with linezolid for more than 7 days were included. Data were collected from medical charts and differences between patients with and without renal insufficiency were analysed. Sixty-two patients (40 men), with a mean age of 56.9 years, were enrolled in this study. At the start of linezolid treatment, 17 patients (27.4%) had impaired renal function. Patients with renal insufficiency had a higher prevalence of diabetes mellitus compared with those with normal renal function (64.7% vs. 22.2%; P = 0.002). At the start of therapy, patients with renal impairment had a higher frequency of elevated blood urea nitrogen (51.0 ± 21.1 mg/dL vs. 18.3 ± 9.7 mg/dL; P < 0.001), elevated serum creatinine (2.3 ± 0.7 mg/dL vs. 0.9 ± 0.3 mg/dL; P < 0.001) and decreased initial haemoglobin (9.2 ± 1.5 g/dL vs. 10.4 ± 1.7 g/dL; P = 0.017). Development of severe thrombocytopenia (<100 × 109/L) was significantly more common in patients with renal insufficiency (64.7% vs. 35.6%; P = 0.039). The incidence of linezolid-associated thrombocytopenia was higher among patients with renal insufficiency. When patients with renal insufficiency are treated with linezolid for more than 2 weeks, the platelet count should be monitored at least twice a week owing to the increased likelihood of thrombocytopenia.