Retapamulin is the first in a new class of topical antibiotics called pleuromutilins. Pleuromutilins selectively inhibit bacterial protein synthesis at a unique site on the 50S subunit of the bacterial ribosome that is distinct from the binding sites of other non-pleuromutilin antibacterial agents that interact with the ribosome.
Due to its distinct mechanism of action, retapamulin does not demonstrate target-specific cross-resistance with other classes of antibacterial agents.
Retapamulin is predominantly bacteriostatic against S. aureus and S. pyogenes
In a phase III study, retapamulin was shown to be superior to placebo in adults and children with impetigo. The clinical success rate was 85.6 per cent versus 52.1 per cent for retapamulin and placebo, respectively.1
In other studies, retapamulin demonstrated noninferiority to two other antibacterial treatments. Retapamulin ointment 1% (twice daily for five days) showed comparable efficacy with sodium fusidate ointment 2% (three times daily for seven days) in adults and children (>9 months) with impetigo (n=519).2
In addition, retapamulin was as effective as oral cefalexin 500mg twice daily for 10 days in the treatment of secondarily infected dermatitis in patients aged nine months and older (n=546). 3
1. GSK Clinical Trial Register. Date accessed: 14.02.08.
2. Oranje A, Chosidow O, Sacchindanand S et al. Topical retapamulin ointment, 1%, versus sodium fusidate ointment, 2%, for impetigo: a randomized, observer-blinded, noninferiority study. Dermatology 2007;215: 331–40.
3. Parish L, Jorizzo J, Breton J et al. Topical retapamulin ointment (1%, wt/wt) twice daily for 5 days versus oral cephalexin twice daily for 10 days in the treatment of secondarily infected dermatitis: results of a randomized
controlled trial. J Am Acad Dermatol 2006;55(6): 1003–13
Further information: GlaxoSmithKline