Optimized dosing regimens for the combinations of sulfonamides and trimethoprim in veterinary medicine

01 February 2023 → 31 January 2026
Research Foundation - Flanders (FWO)
Research disciplines
  • Agricultural and food sciences
    • Veterinary pharmacology and toxicology
Trimethoprim Sulfonamides veterinary medicine PK/PD drug combinations
Project description

SulTAn (SULfonamides and Trimethoprim combinations in ANimals)


Due to the pending constraints for veterinarians to use antibiotics critically important for human health in Europe, the relative use of first-line antibiotics such as the combination of trimethoprim (TMP) and sulfonamides (S) will increase in all animal species in coming years. Unfortunately, for these old drugs, the selection of the doses does not have a solid scientific basis. For S and TMP, the dose ratio of 5:1 found in veterinary formulations is a direct transposition of the ratio of the human drug and has not been established by considering the pharmacokinetics (PK) of the drugs in each animal species, suggesting that the doses are probably suboptimal.

To fill the gaps related to the PK of TMP and S, and to the pharmacodynamics (PD) of their interaction on veterinary pathogens, we have built a consortium of 6 partners recognized as European specialists in veterinary clinical microbiology and pharmacology. Our consortium will carry out PK studies in dogs, horses, pigs,ruminants, poultry and fish and extensive PD studies on most relevant pathogens. By integrating the generated data in PK/PD models, we will be able to compare the efficacy of the current dosing regimens of different sulfonamides and to identify the needed adjustments to ensure efficacy in all species.

Our project will contribute to a responsible and prudent use of TMP/S in veterinary medicine and will benefit human and environmental health by avoiding inefficacious treatments and by limiting the recourse to second-line antibiotics more critical for human health.