From my research, there is a definite correlation between the dosage and severity of adverse reactions.

First of all, the most important factor is dosage PER DAY. Someone who takes 750mg/day of Levaquin for 1 week, is far more likely to suffer a more severe adverse reaction than someone who takes 250mg/day of Levaquin for 3 weeks. As the dosage per day increases, the danger of suffering a serious reaction exponentially rises.

Moreover, another interesting correlation involves the actual presence of a bacterial infection. In my opinion, this could be a serious risk factor for suffering from a serious adverse reaction. Almost all of the most severe adverse reactions have occured when the patient did not have a bacterial infection. However, it is unknown why this happens or whether this correlation is even significant. This could explain why in some clinical trials, adverse events are abnormally low, and also how many people who take the quinolones for a real infection are less likely to get a reaction. If you are suffering from a reaction, it is likely you had no bacterial infection in the first place. Check if you had an infection in the  first place, did you have culture test done, it could have been a virus. One explanation to this interesting correlation could lie in the fact that the drug mainly attacks bacterial DNA, however, it also has an affinity for human DNA. Therefore, since there is no bacteria to kill, the drug inadvertently acts on your own cells. This is another reason why it is important that quinolones should be reserved for drug resistant bacterial infections.

If you are suffering from any reaction, please report it in our Fluoroquinolone Adverse Reaction Report Form.