There is lots of information here:
http://www.levaquin.com/about/levatab.pdf#zoom=100
Also, I recently had a patient who was taking some strong antibiotics (I think Levaquin) and was on coumadin. Since Vitamin K is made in the large intestine by intestinal flora, if that intestinal flora is wiped out by antibiotic therapy, the body does not make enough vitamin K, and with coumadin, the INR can go up (I think the patient's INR was 6 or 7). The patient had a GI bleed, and came in with a blood pressure of 60/30.
Oldiebutgoodie