DOSAGE AND ADMINISTRATION Adults And Pediatric Patients At Least 15 Years Of Age. The usual dose of oral KEFLEX is 250 mg every 6 hours, but a dose of 500 mg every 12 hours may be administered. 1. Practice Guidelines for the Diagnosis and Management of Skin and Soft Tissue Infections: IDSA. Cephalexin (Keflex, Keftabs) is an an antibiotic used to treat bacterial infections of the sinuses, tooth, urinary tract, and throat. Common side effects of Keflex include diarrhea, nausea, abdominal pain, headaches, and vaginitis. Dosage of cephalexin depends on the type of infection. Keflex is commonly prescribed to treat and prevent bacterial infections. A few of the infections that the drug can treat are respiratory tract infections, sinus infections, and skin infections. Cephalexin is used to treat certain infections caused by bacteria such as pneumonia and other respiratory tract infections; and infections of the bone, skin, ears, , genital, and urinary tract. Medical Disclaimer Next Side Effects Add to My Med List More about Keflex (cephalexin) Consumer resources Other brands: get keflex fast Biocef, Daxbia Professional resources Related treatment guides. Special Formulations; Special formulation Prior Authorization Criteria. Consideration will be based on ALL of the following criteria: Member must have a patient specific, clinically significant reason why the immediate release formulation and/or other cost effective therapeutic equivalent medication(s) cannot be used. Keflex is a cephalosporin (SEF a low spor in) antibiotic. It works by fighting bacteria in your body. Keflex is used to treat infections caused by bacteria, including upper respiratory infections, ear infections, skin infections, urinary tract infections, and bone infections. Keflex (cephalexin monohydrate) is an antibiotic used to treat infections caused by bacteria in different parts of the body, including of the nose. User Reviews for Cephalexin to treat Skin or Soft Tissue Infection. Also known as: Daxbia, Keflex, Biocef, Zartan, Panixine. The following information is NOT intended to endorse drugs or recommend therapy.