Aoi noticed: "Because of its broad spectrum of action, Levofloxacin is frequently prescribed empirically for a wide range of infections before the specific causal organism is known. Levaquin is a quinolone antibiotic and these antibiotics seem to be involved in joint problems, specifically tendinitis, thus people at increased risk for this type of problem should be closely monitored. Diarrhea have been reported. Contact your health care provider if you have any questions. Levaquin was initially an extremely successful product both in terms of the revenue it produced and the percentage of success it enjoyed with patients."