Levaquin stays in your system for about 30 to 40 hours. This depends on the patient, but typically it is flushed out of the system within this time frame. The side effects of Levaquin may take a bit longer to diminish, typically "24 to 48 hours after the medication is stopped," according to Everyday Health.
Levaquin is the brand name of the drug levofloxacin, which is an antibiotic that treats bacterial infections. Although the drug may help fight pneumonia and skin infections, it has been known to increase the user's risk of tendonitis and tendon rupture. The manufacturer, Johnson & Johnson, faced numerous lawsuits over this side effect.