Rifampicin-moxifloxacin interaction in tuberculosis treatment: a real-life study

Rifampicin (RMP) has been reported to reduce moxifloxacin (MFX) levels, which may interfere with the effectiveness of MFX in treating tuberculosis (TB).

To study the MFX-RMP interaction in patients receiving MFX with or without RMP as part of their anti-tuberculosis treatment regimen.

Patients with pulmonary TB followed up by the Tuberculosis Out-patient Clinic of the Pulmonary Department, Aristotle University of Thessaloniki, Greece, who underwent treatment with MFX during the periods 1 May 2012-30 April 2014 and 1 January-31 March 2015, were included in the study. MFX levels were compared between 12 patients who were receiving RMP (Group 1) and 10 who were not (Group 2).

The participants did not significantly differ in body mass index, days of MFX treatment or MFX dose/kg. Neither the peak concentration (Cmax) nor the 24 h area under the curve (AUC24) differed significantly between the two groups (Group 1, Cmax median 3.9 [range 1.9-4.5] mg/l; AUC24 29.1 [10-47.4] mg·h/l and Group 2, Cmax 4.1 [2-6.4] mg/l; AUC24 36.5 [14.6-54.2] mg·h/l).

Although a decrease in MFX exposure was observed in the RMP-treated group, the effect was lower than previously reported in a real-life setting. The large variability observed in MFX pharmacokinetics in both groups may suggest the need for dose readjustment in some patients, regardless of RMP co-administration.