Cefalexin, also spelled cephalexin, is an antibiotic that can treat a number of bacterial infections. It kills gram-positive and some gram-negative bacteria by disrupting the growth of the bacterial cell wall. Cefalexin is a beta-lactam antibiotic within the class of first-generation cephalosporins. It works similarly to other agents within. Keflex (cephalexin monohydrate) is an antibiotic used to treat infections caused by bacteria in different parts of the body, including of the nose. Brands Keflex, Biocef Availability Suspension: 125 mg/5mL Capsules: 250 mg, and 500 mg (cephalexin monohydrate) Pharmacology A first generation cephalosporin, cephalexin is a broad-spectrum, bactericidal antibiotic. For the treatment of upper respiratory tract infections, including tonsillitis and/or pharyngitis secondary to Streptococcus pyogenes (i.e., primary rheumatic fever prophylaxis). Antibiotic Drugs Cephalexin. Cephalexin is an orally active first generation bactericidal cephalosporin. Chemical structure Respiratory Tract Infections. Cephalexin capsules are indicated for the treatment of respiratory tract infections caused by susceptible isolates of Streptococcus pneumoniae and Streptococcus pyogenes. Yes, Cephalexin can be used to treat tooth abscess and gum infections. Cephalexin is in a group of drugs called cephalosporins antibiotics and is used to fight bacteria infections in the body. Recent Examples on the Web. The most common organism responsible for perichondritis is a bug called Pseudomonas aeruginosa, a virulent pathogen with the ability to resist many antibiotics, including the cephalexin prescribed by Jessica’s pediatrician. Cephalexin is used in both dogs and cats to treat a variety of bacterial infections, including skin infections, wound infections, bone infections, pneumonia, and bladder infections. Each capsule contains cephalexin monohydrate equivalent to 250 mg, 500 mg or 750 mg of cephalexin. The capsules also contain carboxymethylcellulose sodium, D&C Yellow No. 10, dimethicone, FD&C Blue No. 1, FD&C Yellow No. 6, gelatin, magnesium stearate, microcrystalline cellulose, and titanium dioxide.