Clindamycin
"My dentist prescribed the Clindamycine, 300 mg for treating an infection of the gum, prior root canal procedure later in one week. After taking it for 2 days, I noticed heavy rash on both legs. I immediately stop the use of the Clindamycine. I had very bad diarrhea for 3 weeks. Within 24 hours after Endodontics complete a root canal on me, I got huge swelling in the left knee. I had to go to ER due to swelling and pain. The doctor pulled 90 ml of fluid from my knee and tested for bacterial infection and got  a negative result. I took Naproxine for swelling. The swelling of the left knee went down but right knee and other joints continue swelling for month. My blood was tested for RA arthritis with negative result. Not recommended it."