Retapamulin (DB01256): A Comprehensive Pharmacological and Clinical Monograph

1.0 Executive Summary

Retapamulin is a semi-synthetic, small-molecule antibiotic and the first representative of the pleuromutilin class approved for human topical use.[1] Developed by GlaxoSmithKline, it is marketed under the brand names Altabax and Altargo for the treatment of uncomplicated bacterial skin infections.[1] Its primary clinical indication is for impetigo caused by susceptible strains of

Staphylococcus aureus (methicillin-susceptible only) and Streptococcus pyogenes.[1]

The therapeutic value of retapamulin stems from its novel mechanism of action. It selectively inhibits bacterial protein synthesis by binding to a unique site on the 50S ribosomal subunit, an interaction distinct from all other classes of ribosomal inhibitors.[4] This unique binding confers a low intrinsic potential for target-specific cross-resistance with other established antibiotic classes, a significant advantage in an era of increasing antimicrobial resistance.[4]

Clinical trials have established its efficacy. A 5-day, twice-daily regimen of 1% retapamulin ointment was demonstrated to be significantly superior to placebo in treating impetigo and non-inferior to both topical sodium fusidate and a 10-day course of oral cephalexin for certain skin infections.[7] Its safety profile is favorable, characterized predominantly by mild and infrequent local application site reactions, with minimal systemic absorption in adults and older children.[10]