How long should it take for antibotic to start working on foot Cellulitis? Very sore, and swollen. They gave me SMZ/TMP DS 800-160 TAB Generic for BACTRIM 1 tablet twice a day.  Have take 3 times.  But is not helped any yet and seems to be getting worse. (has  gotten more sore, more swollen, more red and is very painful)  How long should I wait before going back to doctor?
Hello, Very frankly speaking you need to consult your doctor immediately because you need much better broad spectrum antibiotics for your infection.SMZ/TMP combination is inadequate to treat it and rather your problem has worsened after starting this. If you are diabetic, then you may need intravenous antibiotics and admission in the hospital. Thanks