For the treatment of infections in horses, calves, pigs and poultry caused by organisms susceptible to the combination of Sulfadimidine and Trimethoprim.
Directions for use
Do not use in birds which are producing or may in the future produce eggs or egg products for human consumption.
For oral use only.
One level large scoop contains 5g Sulfadimidine and 1g Trimethoprim.
One level small scoop contains 1.25g Sulfadimidine and 0.25g Trimethoprim.
Administer mixed thoroughly with food, on dampened food, or mixed with honey or molasses or dissolved into drinking water.
Horses: One level large scoop per 200kg bodyweight twice daily
Calves: One level large scoop per 50kg bodyweight daily
Pigs: One level large scoop per 50kg bodyweight daily
Poultry: One to two level small scoops per 12L drinking water for
3 - 5 days
Powder 250g, 1kg.
Sulfadimidine 430 mg/g, Trimethoprim 86 mg/g
Sulfadimidine: is a pyrimidine sulfonamide antimicrobial agent. Sulfonamides, being structural analogues of para-aminobenzoic acid (PABA), competitively inhibit the incorporation of PABA into dihydropteric acid, the precursor of folic acid. Subsequent reduction in the level of folic acid reduces the production of nucleic acids in sensitive bacteria. Mammalian cells require preformed folic acid and thus are unaffected by sulfonamides. The anti-bacterial actions of sulfonamides are reduced in the presence of blood, pus and tissue breakdown products, which contain purines and thymidine, as the bacterial requirement for folic acid is decreased in such media. Sulfadimidine is readily absorbed following oral administration and therapeutic plasma levels are rapidly attained. Sulfadimidine is widely distributed to all body
tissues and fluids.
Concentrations are above plasma levels in kidney; similar to plasma levels in pleural, peritoneal, synovial and ocular fluids; slightly lower in CSF, muscle and milk. Sulfadimidine undergoes extensive metabolism via acetylation, hydroxylation, oxidation and conjugation. The parent compound and its metabolites are excreted predominantly in the urine by glomerular filtration. Sulfadimidine undergoes passive tubular resorption prolonging the time course of drug action. Plasma half-life in the horse has been variously estimated as between 6.4 and 9.8 hours.
Trimethoprim is a diaminopyrimidine antimicrobial agent. It acts by preventing the reduction of dihydrofolate to tetrahydrofolate which is required by bacteria for biosynthesis of purines, pyrimidines and some amino acids.
Trimethoprim is readily absorbed from the gastrointestinal tract and like sulfadimidine, rapidly reaches therapeutic levels in plasma. It is widely distributed in body tissues/fluid including bone, prostate, CSF, pleural, peritoneal, synovial and ocular fluids. Studies in humans and several animal species have demonstrated that trimethoprim reaches higher concentrations in all tissues, except brain, than those achieved in plasma. The drug is extensively metabolised in the horse and is excreted in the urine by glomerular filtration and active tubular secretion. Plasma half-life in the horse has been variously estimated as between 4.1 and 4.6 hours.
Sulfadimidine and trimethoprim have similar anti-bacterial spectra, trimethoprim being approximately 20 times more potent that sulfadimidine. The combination blocks two sequential obligate enzymatic reactions in the microbial folate synthetic pathway. A synergistic action is demonstrated by the enhanced antimicrobial activity (potentiation) of the combination compared with the antimicrobial activity of either agent singly. The minimum inhibitory concentrations (MICs) of the combination for susceptible bacteria are substantially lower than those of either of the individual agents. The combination of sulfonamide/trimethoprim is bactericidal while either drug alone is bacteriostatic. Folate-synthesising bacteria which are resistant or moderately resistant to either drug alone are frequently susceptible to the combination. The correlation of anti-bacterial sensitivity in vitro cf. in vivo is among the highest of all antimicrobial agents. The spectrum of bacteria sensitive to the combination includes: Sensitive organisms include Streptococci, Staphylococci, Enterobacter, Corynebacterium (excluding Corynebacterium [Rhodoccus] equi) Salmonella, Shingella, Pasteurella, Haemophilius, Klebsiella, Proteus sp, Fusonbacterium, and most E. coli; some Brucella and Nocardia sp. Most Pseudomonas spp are insensitive.
Resistance to the combination by Gram-negative bacteria is associated with the presence of R Factors. Resistance by Staphlyoccus aureus and Haemophilius spp is chromosomal and is rarely encountered except in patients previously exposed to the combination.
Administration to animals with a history of sulfonamide or trimethoprim sensitivity.
In cases where the infection is non-responsive or chronic a culture and sensitivity test should be undertaken.
Horses: meat: – 28 days.
Other – Do not use less than 15 days before slaughter for human consumption. Do not use in birds which are producing or may in the future produce eggs or egg products for human consumption
Store below 30ºC (room temperature). Protect from light.