Pharmacokinetics of quinolones with special reference to the respiratory tree

Successful treatment of respiratory tract infections with the fluoroquinolones requires knowledge about whether the prescribed antibiotic will reach the site of infection at clinically active concentrations. The difficulty in extrapolating pharmacokinetic information from animal models to man has resulted in new approaches to determine the distribution of antibiotic within the human lung. Bronchoalveolar-lavage (BAL) allows the collection of epithelial-lining-fluid, alveolar macrophages, bronchial mucosal samples and sputum, thereby permitting measurement of the cellular and extracellular concentrations of an antibiotic. All fluoroquinolones show similar patterns of penetration into the lung parenchyma, bronchial mucosa or bronchial secretions. The main differences between these agents concern antibacterial potency and the nature, frequency and severity of adverse reactions. Many respiratory infections are caused by obligate or faculative intracellular pathogens, which are likely to be eradicated by the intracellular and extracellular concentrations of quinolones achieved and is supported by models of phagocytic cell function.