Sulfadimethoxine is a sulfonamide antibiotic that is active against Gram-negative and Gram-positive bacteria and other microorganisms.1 It inhibits recombinant P. carinii dihydropteroate synthase (DHPS; IC50 = 25 nM), an enzyme required for folate biosynthesis, in a cell-free assay.2 Sulfadimethoxine is active against S. aureus, S. pneumoniae, K. pneumoniae, and E. coli in a disc assay.1 It is also active against C. spiroforme isolates from rabbits (MIC90 = 256 μg/ml) and certain M. bovoculi isolates from keratoconjunctivitis infections in cows (MIC50 = ≤256 μg/ml).3,4 Sulfadimethoxine is efficacious against S. pneumoniae, K. pneumoniae, and E. coli systemic infections in mice with 50% curative dose (CD50) values of 79.7, 2.7, and 12.2 mg/kg, respectively. It is also efficacious against H. capsulatum systemic fungal infections in mice (CD50 = 300 mg/kg).1
1.B?hni, E., Fust, B., Rieder, J., et al.Comparative toxicological, chemotherapeutic and pharmacokinetic studies with sulphormethoxine and other sulphonamides in animals and manChemotherapy14(4)195-226(1969) 2.Hong, Y.-L., Hossler, P.A., Calhoun, D.H., et al.Inhibition of recombinant Pneumocystis carinii dihydropteroate synthetase by sulfa drugsAntimicrob. Agents Chemother.39(8)1756-1763(1995) 3.Agnoletti, F., Ferro, T., Guolo, A., et al.A survey of Clostridium spiroforme antimicrobial susceptibility in rabbit breedingVet. Microbiol.136(1-2)188-191(2009) 4.Angelos, J.A., Ball, L.M., and Byrne, B.A.Minimum inhibitory concentrations of selected antimicrobial agents for Moraxella bovoculi associated with infectious bovine keratoconjunctivitisJ. Vet. Diagn. Invest.23(3)552-555(2011)