Hematologic toxicity of linezolid

This study was based on a medical record review from an academic VA medical center:

Patients. Four hundred forty-four patients (mean age 63.7 yrs) who received 544 courses of linezolid from 2004–2007.

Measurements and Main Results

The frequencies of grade 1–2 and grade 3–4 thrombocytopenia were 7.6% and 5.2%, respectively. Grade 3–4 anemia developed in 18.8% of courses; each of the patients had baseline grade 1–2 anemia. Linezolid was discontinued because of toxicity in 35 (6.4%) of the 544 courses. Independent variables associated with grade 3–4 thrombocytopenia included a baseline hemoglobin level of less than 10.5 g/dl, presence of immunosuppression, and a baseline platelet count of 50–99.9 × 103/mm3. Independent variables associated with development of grade 3–4 anemia included presence of a cardiovascular condition, urologic condition, immunosuppression, and a baseline platelet count of 50–99.9 × 103/mm3. Other toxicities reported with linezolid included diarrhea (6.6% of courses), followed by nausea (4.4%) and vomiting (4.0%).

Conclusion. The overall rates of thrombocytopenia and anemia for patients receiving linezolid were found to be higher than those in phase III clinical trials.