After prophylactic irrigation of the intact urinary bladder, neomycin and polymyxin B are absorbed in clinically insignificant quantities. A neomycin serum level of 0.1 µg/mL was observed in three of 33 patients receiving the rinse solution. This level is well below that which has been associated with neomycin-induced toxicity.
When used topically, polymyxin B sulfate and neomycin are rarely irritating.
The prepared NEOSPORIN G.U. Irrigant Sterile solution is bactericidal. The aminoglycosides act by inhibiting normal protein synthesis in susceptible microorganisms. Polymyxins increase the permeability of bacterial cell wall membranes. The solution is active in vitro against
Klebsiella and Enterobacter species
Neisseria species, and
It is not active in vitro against Serratia marcescens and streptococci.
Bacterial resistance may develop following the use of the antibiotics in the catheter-rinse solution.