Levaquin (levofloxacin) is a fluoroquinolone antibiotic that needs to be taken by people to whom it was prescribed. It treats bacteria-induced infections of the skin, kidneys, prostate, bladder, as well as pneumonia and bronchitis. In some cases patients taking this medicine report the following side effects: vaginal itching, constipation, muscle pain, vaginal discharge, dizziness, restlessness, nightmares, mild skin itching, nausea, diarrhea, insomnia, and headache. These are typically mild and short-lived. However, you should watch for more serious side effects that are quite rare but need to be reported as soon as possible: fast heartbeat, hallucinations, dizziness, fainting, sudden joint pain and joint swelling, seizure, unusual weakness, decreased urination, depression pale skin, jaundice, watery or bloody diarrhea, and unusual behavior. To benefit the most from your treatment make sure you mention any of the following medicines if you are taking them at the moment or are planning to use them later on: insulin or diabetes medication, blood thinners, nonsteroidal anti-inflammatory drugs (NSAID) or oral steroids.