We describe linezolid tissue penetration in two diabetic patients with lower-extremity ulcers, measured by in vivo microdialysis, before and after hyperbaric oxygen (HBO2) therapy. Each diabetic patient received a single orally administered dose of linezolid 600 mg within one week of initiating an eight-week HBO2 course for treatment of his or her Wagner Grade 3 lower-extremity wound. A microdialysis catheter was placed at the margin of the wound for collection of extracellular tissue fluid.

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... od and tissue samples were collected hourly over the following 12 hours. After completion of HBO2, each patient received a second dose of linezolid 600 mg, the microdialysis catheter was reinserted in same location, and blood/tissue samples were recollected for comparison. Patient 1 completed all eight weeks of HBO2, while Patient 2 completed only five of eight weeks. Based on the 12-hour area under the curve ratio between extracellular tissue fluid and blood, linezolid penetration was 0.474 and 0.479 for Patients 1 and 2, respectively, at the beginning of HBO2. After completing HBO2, penetration improved in both patients to 0.950 and 0.757, respectively. Tissue concentrations of linezolid at the site of lower extremity ulcers improved following a course of HBO2 in two patients with diabetes.