Retapamulin: a new topical antibiotic for the treatment of uncomplicated skin infections.

Retapamulin is the first agent in the new pleuromutilin class of antibacterials to become commercially available for clinical use in humans. Retapamulin acts as a potent inhibitor of bacterial protein synthesis and has a unique mode of antibiotic action. To date, retapamulin has not demonstrated any clinically relevant, target-specific crossresistance with other antibiotic classes, and has shown a low potential for resistance selection in vitro. In preclinical studies, retapamulin demonstrated pronounced in vitro activity against staphylococcal, streptococcal and anaerobic Gram-positive clinical isolates associated with skin and skin structure infections. Clinical pharmacology studies showed low systemic exposure with topical use of retapamulin, and a favorable tolerability profile. In clinical efficacy trials involving pediatric and adult patients who received retapamulin twice daily for five days, retapamulin was highly effective in the treatment of impetigo, secondarily infected traumatic lesions and secondarily infected dermatitis. Further, the clinical efficacy and safety profile of retapamulin was comparable to that of commonly used oral and topical antibiotics. Retapamulin was also clinically effective against isolates resistant to existing therapies. As a 1% ointment, retapamulin has been approved in the United States for the treatment of impetigo and in Europe for the shortterm treatment of impetigo and infected small lacerations, abrasions and sutured wounds.