Penetration of levofloxacin into paranasal sinuses mucosa of patients with chronic rhinosinusitis after a single 500 mg oral dose.

Respiratory fluoroquinolones are currently considered by several guidelines among the most effective antimicrobial agents for the treatment of acute bacterial rhinosinusitis. The aim of this study was to assess levofloxacin penetration into paranasal sinuses mucosa of 15 patients with chronic rhinosinusitis 1h (n = 4), 2 h (n = 5) and 3 h (n = 6) after a single 500 mg oral dose. Levofloxacin concentrations in plasma and tissue samples were assessed by means of HPLC. Median of mucosal concentrations were 0.96 mg l(-1) at 1 h, 2.50 mg l(-1) at 2 h, 5.84 mg l(-1) at 3 h. Average paranasal sinuses mucosa-to-plasma ratios raised from 1.46 at 1 h, to 1.81 at 2 h and to 2.56 at 3 h. These data are consistent with 500 mg oral levofloxacin ensuring appropriate therapeutic exposure in sinonasal tissue of patients with chronic rhinosinusitis, the concentrations between 1 and 3 h post-dosing being almost always higher than the MIC90 against the major bacterial pathogens responsible for upper respiratory tract infections.