Ofloxacin and pulmonary tuberculosis.

We read with great interest the article by Kohno et at published in the December, 1992, issue of Chest concerning the comparison of ofloxacin and ethambutol in the treatment of pulmonary beos’ We wish to supplement and reiterate on several issues concerning the potential role of ofloxacin for the treatment of pulmonary tuberculosis. As referenced by the authors, ofloxacin has distinct activity against intracellular Mycobacterlum tuberculosis.2 It is also well known that ofloxacin, like other fluoroquinolones are well concentrated within alveolar macrophages.’ Thus it is likely that ofloxacin like pyrazinamide has sterilizing capacity, which is a drug characteristic that contributes to the success of short-course chemotherapy. Indeed, this issue has been explored in another study, though comparing ciprofloxacin (rather than ofloxacin) with pyrazmnamide.4 In that study, all patients received 6 months of daily rifampicin and isoniazid with either 2 months of ethambutol and pyrazinamide or 4 months of ciprofloxacin. There has been a rapid fall in culture positivity in the standard regimen group and a more gentle decline in the ciprofloxacin group. However, this does not reach statistical significance. The other aspects that warrant investigation are the early bactericidal effects and the prevention of emergence of resistance.4 Concerning adverse reactions, from the finding of Kohno and coauthors, it does seem that ofloxacin is as well tolerated as ethambutol with particular reference to the liver. We have lately reported the relatively good tolerance of ofloxacin in 29 patients with hepatic dysfunction and pulmonary tuberculosis.’ This property might be unique to ofloxacin because it is normally handled almost exclusively by renal clearance though changes secondary to hepatic dysfunction have not been completely unraveled.6 We also concur with Kohno and ca-authors that ofloxacin might have a place in the treatment of multidrug resistant pulmonary tuberculosis. In addition to our earlier report,7 we have treated another 12 patients with bacilli resistant to at least streptomycin, isoniazid, and rifampicin In vitro with ofloxacin. Two patients received 400 mg ofloxacin once daily. Ten patients received 600 mg to 800 mg ofloxacin once daily. Other accompanying drugs used include kanamycin, ethionamide, cycloserine, ethambutol, and pyrazinamide depending on guidance provided by in vitro susceptibilities. All 12 patients achieved culture conversion within 4 months of commencement of chemotherapy.