In Phase III clinical trials (usually 3,000-6,000 patients in various indications), the overall drug-related fluoroquinolone discontinuation rates average 3-4% (38, 41, 42, 44, 47-49). With levofloxacin, Japanese studies recorded rates of < 1.5%; in comparison to 3.7% (maximum) in the USA. These rates are class normal, in contrast to those for grepafloxacin and trovafloxacin (6-7%), which related primarily to GI intolerance and dizziness, respectively. Both of these agents were subsequently withdrawn for unrelated reasons but it is interesting to note the higher rate of discontinuation compared with safer class members.