urinary tract infection
"This was prescribed for my son who has Cerebral Palsy and is confined to a wheelchair. He became swollen in his legs ankles and feet. Took for 48 hours and discontinued as the swelling progressed. Rushed to MD, had to take a different medicine (Macrobid). Thankfully the swelling subsided in a few days. I have read many horror stories about the side effects of this medicine - some permanent! I do not recommend. 
Please keep in mind that a urine sample should always be cultured, not just tested with a dipstick as the treatment really depends on the type of bacteria that's causing the uti."