Orally administered moxifloxacin prolongs QTc in healthy Chinese volunteers: a randomized, single-blind, crossover study.

Aim: To investigate the QT/QTc effects of orally administered moxifloxacin in healthy Chinese volunteers.

Methods: This was a single-blinded, randomized, single-dose, placebo-controlled, two-period cross-over study. A total of 24 healthy Chinese volunteers were enrolled, randomly assigned to two groups: one group received moxifloxacin (400 mg, po) followed by placebo with a 7-d interval, another group received placebo followed by moxifloxacin with a 7-d interval. On the days of dosing, 12-lead 24 h Holter ECGs were recorded and evaluated by an ECG laboratory blind to the treatments. Blood samples were collected to determine plasma concentrations of moxifloxacin.

Results: The orally administered moxifloxacin significantly prolonged the mean QTc at all time points except 0.5 h post-dose. The largest time-matched difference in the QTcI was 8.35 ms (90% CI: 5.43, 11.27) at 4 h post-dose. The peak effect on QTcF was 9.35 ms (90% CI: 6.36, 12.34) at 3 h post-dose. A pharmacokinetic-QTc model suggested a 2.084 ms increase in the QTc interval for every 1000 ng/mL increase in plasma concentration of moxifloxacin. In addition, the orally administered moxifloxacin was well tolerated by the subjects.

Conclusion: Orally administered moxifloxacin significantly prolongs QTc, which supports its use as a positive control in ICH-E14 TQT studies in Chinese volunteers.