I had knee replacement about 7 weeks ago, developing a superficial infection so my doctor prescribed an anti-biotic. After about 1/2 taken, I began to suffer pins and needles feeling in my knees and lower legs, but not in feet. Also, slightly from my wrists to elbows. It stings so bad. I've called my doctor and will see him Monday, but I'm not sure I can wait til then. Really bad at night - can't sleep! Thanks for your help.