kidney infections
"I was treated for kidney infection with 750 mg once a day for 7 days. Like other reviewers I had similar side effects ; terrible headaches , nausea, sleeplessness, aches in joints.  I'm an avid tennis player and worry about tendon damage. I must admit the back pain is better in two days but still have frequent urination issues. The doctor ordered a culture which should be back soon and perhaps offer another alternative with fewer side effects."