032. Moxifloxacin pharmacokinetics in patients with lung infection from 
non-tuberculous mycobacteria

Background: Lung infection from non-tuberculous mycobacteria (NTM), represent a significant clinical problem due to its increased incidence and difficult management. Moxifloxacin (MXF) can play an important role in the treatment of these infections, especially when microbial resistance is an issue.

Objective: To evaluate MXF pharmacokinetics in patients with lung infection from NTM.

Methods: Four immunocompetent patients (three men and one woman), aged 62±11 years, who were received 400 mg MXF per os daily, were enrolled in the study. Three of them had infection from M. avium complex (MAC) resistant to clarithromycin and the fourth had infection from M. kansasii resistant to rifampicin. The pharmacokinetic study took place in steady state condition. Serial blood samples were collected during a 24-h time interval after drug administration. The MXF concentration in plasma was determined by high-performance liquid chromatography (HPLC). The area under the concentration-time curve from time zero to 24 h (AUC₂₄) was calculated by the trapezoidal rule.

Results: Mean peak MXF concentration in plasma (Cmax) was 3.29±1.01 mg/L and was achieved (tmax) 1.25±0.29 h after drug administration. AUC₂₄ was 31.81±12.47 mg/L×h. A large interindividual variability was observed in Cmax (range 1.94 to 4.21 mg/L) and AUC₂₄ (range 14.95 to 43.86 mg/L×h) respectively. All patients had clinical and microbiological improvement after a two years course of therapy.

Conclusions: In patients with lung infection from NTM and resistance to primary agents, moxifloxacin can be effective as part of therapeutic regimen. However, the variability of the observed blood levels of the drug among the patients, may suggest a possible increase of its daily dose.

Keywords: Moxifloxacin; tuberculosis; bacteria