Cloxacillin is an antibiotic useful for the treatment of a number of bacterial infections. It is semisynthetic and in the same class as penicillin. Cloxacillin is used against staphylococci that produce beta-lactamase, due to its large R chain, which does not allow the beta-lactamases to bind. This drug has a weaker antibacterial activity than benzylpenicillin, and is devoid of serious toxicity except for allergic reactions.Cloxacillin was discovered and developed by Beecham. It is sold under a number of trade names, including Cloxapen, Cloxacap, Tegopen and Orbenin.