CLINICAL PHARMACOLOGY

Mupirocin is produced by fermentation of the organism Pseudomonas fluorescens. Mupirocin inhibits bacterial protein synthesis by reversibly and specifically binding to bacterial isoleucyl transfer-RNA synthetase. Due to this mode of action, mupirocin shows no cross resistance with chloramphenicol, erythromycin, fusidic acid, gentamicin, lincomycin, methicillin, neomycin, novobiocin, penicillin, streptomycin, and tetracycline.

Application of 14C-labeled mupirocin ointment to the lower arm of normal male subjects followed by occlusion for 24 hours showed no measurable systemic absorption (<1.1 nanogram mupirocin per milliliter of whole blood). Measurable radioactivity was present in the stratum corneum of these subjects 72 hours after application.

Microbiology: The following bacteria are susceptible to the action of mupirocin in vitro: the aerobic isolates of Staphylococcus aureus (including methicillin-resistant and b-lactamase producing strains), Staphylococcus epidermidis, Staphylococcus saprophyticus, and Streptococcus pyogenes.

Only the organisms listed in INDICATIONS AND USAGE have been shown to be clinically susceptible to mupirocin