Metal cations such as aluminum, magnesium, ferrous sulfate, and zinc are thought to form chelation complexes with fluoroquinolone antibiotics and prevent the drugs from being absorbed. Sucralfate, which has a high aluminum content, reduces the bioavailability of ciprofloxacin to approximately 4%. The concomitant administration of ciprofloxacin and sucralfate resulted in treatment failure for a patient with prostatitis and a subsequent 5-day hospitalization. Fluoroquinolone antibiotics should be administered at least 2 hours before agents containing metal cations to allow for their absorption. In addition, sucralfate should not be administered less than 6 hours before fluoroquinolone antibiotic administration.