Cephalexin is a member of the cephalosporin group of antibiotics, and is prescribed for a variety of mild infections. It is not as wide ranging in its action as some other antibiotics, but it is useful for treating infections of the respiratory tract as well as skin conditions (including acne) and soft tissue infections.

The antibiotic can be prescribed on its own or as a follow up after an injection of a stronger cephalosporin has been administered. It is also used as a low dose antibiotic that can be administered over an extended period of time. It is a fairly short acting antibiotic and therefore is not as convenient as some others because it must be taken fairly frequently (every four hours).

Ref: www.3dchem.com