Role of fluoroquinolones in the treatment of tuberculosis

Abstract

INTRODUCTION: The increasing incidence of multidrug-resistant (MDR) and extensively drug-resistant (XDR) strains of Mycobacterium tuberculosis is hampering efforts to control the global tuberculosis (TB) epidemic. Although treatment of drug-susceptible TB is possible in ≥ 95% of disease cases, long (≥ 6 months) duration of supervised combination therapy is challenging. Non-adherence to treatment often results in much lower cure rates. Treatment of MDR-TB and XDR-TB is far less effective. The aim of this review is to summarize the current status of fluoroquinolones in shortening the duration of drug-susceptible pulmonary TB and in improving the outcome of MDR-TB/XDR-TB.
METHODS: All the relevant articles were identified through a search of PubMed and Scopus databases by using search terms like tuberculosis (or M. tuberculosis), fluoroquinolones, drug-susceptible TB, MDR-TB, XDR-TB, combination therapy, treatment regimens, treatment duration, drug target and drug resistance. The current literature on the role of fluoroquinolones in the treatment of TB was reviewed.
RESULTS: The fluoroquinolones, particularly newer compounds such as levofloxacin, moxifloxacin and gatifloxacin, have bactericidal activity against M. tuberculosis, excellent oral bioavailability, favorable safety profile and no cross-resistance with other first-line anti-TB drugs. Data from phase II trials of fluoroquinolones-containing regimens for shortening the duration of treatment for pulmonary TB are encouraging and phase III trials are currently underway. The fluoroquinolones are also effective as substitute agents for those individuals who are intolerant to first-line drugs. Several studies and clinical trials have also supported the use of fluoroquinolones in patients with MDR-TB/XDR-TB.
DISCUSSION: The fluoroquinolones-containing regimens are being tested to shorten the duration of treatment for pulmonary TB to 4 months. They are also regarded as one of the two cornerstone drugs for the treatment of MDR-TB/XDR-TB. However, they are also among the commonly prescribed antibiotics for lower respiratory tract infections and are becoming increasingly associated with delayed treatment and resistance in TB. If these trends are not reversed soon, we may lose fluoroquinolones as effective anti-TB agents very rapidly.