Take the full dosage schedule of Keflex, even if you're feeling better in a few days. Stopping the medication too early may allow bacteria to continue to grow resulting in a relapse of the infection. Additional cephalosporin antibiotics as this is likely to result in an overdose. Stopping the medication too early may allow bacteria to continue to grow resulting in a relapse of the infection. Cephalexin is a broad-spectrum antibiotic used to treat bacterial infections of the skin, urinary tract, respiratory tract, bones, and joints.