Linezolid-associated thrombocytopenia.

A 76-year-old man with end-stage renal disease and multiple comorbidities developed progressive thrombocytopenia while receiving linezolid therapy. His platelet count dropped by more than 50% from the baseline after one week of treatment. He subsequently experienced active gastrointestinal bleeding requiring blood transfusion. Drug-induced thrombocytopenia was suspected, and linezolid was discontinued after 10 days of therapy. However, his platelet count continued to decline and reached a nadir of 31 × 103/mm3 on day 13 of his hospital stay. This hematologic adverse effect resolved within nine days after linezolid cessation (day 19). Multiple risk factors for developing linezolid-associated thrombocytopenia were identified in this patient. The accumulation of linezolid and its metabolites because of reduced renal clearance may be contributory to this adverse drug reaction. Clinicians should be vigilant in monitoring platelet counts in elderly patients who are receiving linezolid, especially in those who are at risk for bleeds or who have end-stage renal disease.