Good renal function is important in the elimination of all of these antibiotics, even when only small amounts of unchanged drug are detectable in the urine. The extent of metabolism varies by compound. For example, sparfloxacin undergoes a much more limited metabolism than ciprofloxacin. The fluoroquinolones are generally well tolerated with minimal side effects when used appropriately. Some of the adverse effects which are listed in the drugs' monographs have not yet been observed in humans.
Nausea is the most common complaint, followed by abdominal discomfort, vomiting, and diarrhea.
CNS stimulation may occur as a result of fluoroquinolone binding to and antagonizing GABA receptors in the brain. In the event that seizures occur, benzodiazepines are an appropriate treatment. Crystalluria is related to pH dependent solubility of the compounds themselves. To prevent this complication, patients should be well hydrated and alkalinity of the urine should be avoided. The rate of anaphylaxis to ciprofloxacin is 1.2 per 100,000 prescriptions.