Effect of sucralfate on absorption of norfloxacin and ofloxacin

The effect of sucralfate on the pharmacokinetics of norfloxacin and ofloxacin was assessed in two separate crossover studies with healthy volunteers. In both studies, eight subjects were randomized to one of the following three regimens: a 400-mg dose of norfloxacin or ofloxacin alone, norfloxacin or ofloxacin given simultaneously with sucralfate (1 g), or norfloxacin or ofloxacin given 2 h before sucralfate. Coadministration of sucralfate reduced the bioavailability of norfloxacin and ofloxacin by 91% (P < 0.001) and 61% (P < 0.001), respectively. However, when norfloxacin and ofloxacin were given 2 h before sucralfate, there were no significant alterations in the pharmacokinetics of either fluoroquinolone. Similar results were obtained when the cumulative amount of each fluoroquinolone recovered in the urine was used to calculate bioavailability. To avoid these interactions and potential therapeutic failures, norfloxacin and ofloxacin should not be used concurrently with sucralfate. The interaction can be minimized by maximizing the time between the fluoroquinolone dose and the previous sucralfate dose and giving the fluoroquinolone at least 2 h before another sucralfate dose.