Effect of calcium supplements on the oral bioavailability of moxifloxacin in healthy male volunteers.

OBJECTIVE

To investigate the effect of concomitant calcium administration on the pharmacokinetics and tolerability of moxifloxacin.

DESIGN

This was a nonblinded, randomised, single dose, crossover study in healthy male volunteers.

PARTICIPANTS

12 healthy male Caucasians (age 24 to 45 years) were enrolled in the study.

METHODS

In each of the 2 study periods, each volunteer received a single oral morning dose of moxifloxacin 400mg after an overnight fast. In 1 of the study periods, Ca2+ 500mg (Calcium-Sandoz Forte) was administered immediately before, and 12 and 24 hours after, moxifloxacin (total of 3 doses of Ca2+). The 2 study periods were separated by a washout period of at least 2 weeks.

RESULTS

Moxifloxacin was well tolerated throughout the study. There was no difference in the area under the plasma concentration-time curve from zero to infinity [AUCinfinity; geometric mean (SD)] of moxifloxacin [32.2 (1.24) vs 33.0 (1.26) mg/L x h, with vs without Ca2+]. Maximum plasma concentration (Cmax) [2.29 (1.27) vs 2.71 (1.33) mg/L, with vs without Ca2+] slightly decreased by approximately 16% and the time to Cmax [median (range)] tended to be slightly prolonged [2.5 (0.8 to 3) vs 0.9 (0.5 to 2.5) hours, with vs without Ca2+].

CONCLUSIONS

The extent of absorption of moxifloxacin is not affected by concomitant Ca2+ intake, whereas the rate of absorption is slightly reduced, an effect not considered to be of clinical relevance. Hence, moxifloxacin may be administered together with Ca2+ without dosage adjustments or special recommendations.