Cefalexin (INN) or more commonly cephalexin is a first-generation cephalosporin antibiotic introduced in 1967 by Eli Lilly and Company. It is an orally administered agent with a similar antimicrobial spectrum to the intravenous agents cefalotin and cefazolin. It was first marketed as Keflex (Lilly), and is marketed under several other trade names. As of 2008, cefalexin was the most popular cephalosporin antibiotic in the United States, with more than 25 million prescriptions of its generic versions alone, for US$255 million in sales (though less popular than two other antibiotics, amoxicillin and azithromycin, each with 50 million prescriptions per year). Cefalexin is used to treat a number of infections including: otitis media, streptococcal pharyngitis, bone and joint infections, pneumonia, cellulitis, and urinary tract infections. It may be used to prevent bacterial endocarditis. In addition to being a rational first-line treatment for cellulitis, it is a useful alternative to penicillins in patients with penicillin hypersensitivity. In patients with mild or questionable history of penicillin allergy, cephalasporins are now thought to be relatively safe.
Contributions by Fvasconcellos, CheMoBot, and Jmh649.