Probable vancomycin-induced neutropenia

Objective: To report a case of vancomycin-induced neutropenia and provide a review of the literature. Case Summary: A 64-year-old white man was treated with intravenous vancomycin 1.5 g/day for finger osteomyelitis. He developed neutropenia after 21 days of vancomycin therapy. The absolute neutrophil count reached a nadir of 418 cells/mm(3) during vancomycin use and returned to normal 7 days after its discontinuation. The eosinophil count was also elevated during the neutropenic episode and probably related to vancomycin. Based on the Naranjo probability scale, the reaction was probably related to vancomycin use. Discussion: Articles describing cases of vancomycin-induced neutropenia were identified. All patients developed neutropenia as a result of vancomycin therapy greater than or equal to12 days. Neutrophil counts generally increased following discontinuation of vancomycin. One article reported successful resolution of neutropenia and infection by switching the patient's therapy to the structurally related antibiotic agent teicoplanin. Other patients were continued on vancomycin therapy, and neutropenia was treated with moderate to good success with filgrastim. Rechallenge was not generally attempted. The mechanism of neutropenia caused by vancomycin is unclear, but appears to be immune-mediated. Conclusions: Vancomycin therapy should not be prolonged unless absolutely necessary, and therapy should be reserved for patients with clear indications for the drug, such as infections due to gram-positive organisms resistant to other therapies. Patients should have periodic assessment of white blood cell and neutrophil counts with consideration to discontinue vancomycin if neutropenia develops.