A Review of the Clinical Pharmacology of Moxifloxacin, a New 8-Methoxyquinolone, and its Potential Relation to Therapeutic Efficacy

Abstract

Moxifloxacin is a new 8-methoxyquinolone with enhanced activity in vitro against Gram-positive pathogens and maintenance of activity against Gram-negative organisms. It is active against common, less common and atypical respiratory tract pathogens. The drug is rapidly absorbed, with peak plasma concentrations reached within 1 to 4 hours after treatment, and the long half-life (11.4 to 15.6 hours) makes it suitable for once-daily administration. There are no significant interactions between moxifloxacin and other drugs/substances or food, although staggered dose administration is needed if iron or other divalent cation-containing substances are to be administered to patients taking moxifloxacin. Moxifloxacin accumulates in lung epithelial lining fluid, bronchial mucosa and alveolar macrophages at concentrations that are considerably higher than the minimum inhibitory concentrations (MIC90S) of the most common respiratory pathogens (Streptococcus pneumoniae, Haemophilus influenzae and Moraxella catarrhalis). In terms of pharmacokinetic indices used to predict clinical outcome, moxifloxacin’s peak serum concentration (Cmax):MIC exceeds the recommended minimum (>8 to 10), and the area under the inhibition curve (AUIC) values found for moxifloxacin exceed the minimum value for patients with serious infections (>125 mg/L·h). Thus, the antibiotic should achieve a high clinical success rate, although the outcome of clinical trials is awaited to confirm moxifloxacin as an important new antibiotic for a range of community respiratory infections.