I took Levaquin - which has been very effective for me, with no yeast infections for a change - for a bronchitis I had a week ago. I am 67 and got it from my preschool granddaughter. Usually, I take this for occasional Urinary Tract Infections, and since I tolerate it so well, my Dr. prescribed it for the bronchitis. After 3 days I began to notice my knees were hurting terribly, and I had lots of muscle pain. I didn't know it was possible side effects from the medication until I read this website. I think it's an amazingly beneficial drug for infection, but I now know I have to report that as a side effect to my Dr. (Stopped taking med 2 days ago; no more knee or muscle pain)