Aqueous and vitreous penetration of linezolid and levofloxacin after oral administration.

PURPOSE To evaluate the time course of drug concentrations achieved in aqueous (AQ), vitreous (V), and serum (S) compartments after oral administration of linezolid and levofloxacin. DESIGN Randomized, clinical trial. METHODS SETTINGS Clinical practice. PATIENT POPULATION Sixteen patients (16 eyes) undergoing vitrectomy who had not had a prior pars plana vitrectomy in the study eye were randomly assigned to one of 4 groups. INTERVENTION AQ, V, and S samples were obtained from all subjects after single concomitant doses of linezolid 600 mg and levofloxacin 750 mg between 1 and 12 h before the procedure: group A = 1-3 h; group B = 3-6 h; group C = 6-9 h; group D = 9-12 h. MAIN OUTCOME MEASURES AQ, V, and S concentrations of linezolid and levofloxacin. RESULTS Overall mean concentrations ± standard deviation (μg/mL) achieved by linezolid in AQ, V, and S compartments were 3.32 ± 2.06, 2.98 ± 1.87, and 7.91 ± 3.94, respectively. Overall mean concentrations ±standard deviation (μg/mL) achieved by levofloxacin in AQ, V, and S compartments were 2.19 ± 1.92, 1.95 ± 1.27, and 7.38 ± 3.47, respectively. CONCLUSIONS Single concomitant doses of linezolid and levofloxacin achieved AQ and V concentrations above the minimum inhibitory concentration for 90% of common ocular gram-positive and gram-negative pathogens up to 12 h after administration. The combination of linezolid and levofloxacin represents a viable option for the prophylaxis and management of endophthalmitis.