Back to Antimicrobial Agents
synonymous with: Cotrimoxazole, SMX-TMP, TMP-SMX, TMP-SDZ, SDZ-TMP, Co-trimazine
Bactrim, Bactrim-DS, Septra, Septra DS, Cotrim, Cotrim-DS (trimethoprim-sulfamethoxazole)
40 mg trimethoprim/200 mg sulfamethoxazole
80 mg trimethoprim/400 mg sulfamethoxazole
160 mg trimethoprim/800 mg sulfamethoxazole (double strength tablet)
240 mg/5 mL (containing 40 mg trimethoprim and 200 mg sulfamethoxazole) suspension
When used alone the sulfonamides are bacteriostatic, and the trimethoprim is bactericidal, but when used in combination form the potentiated sulfas are bactericidal.
This combination drug has broad-spectrum activity. It is effective against Gram-positive bacteria such as streptococci and some strains of staphylococcus. Gram-negative organisms such as CAR bacillus and those of the enterobacteriaceae are also susceptible to this drug. However, it does not appear to be effective against either mycoplasma, or Pseudomonas aeruginosa. The combination of trimethoprim / sulfa also appears to inhibit some protozoa (e.g., Pneumocystis carinii).
Trimethoprim / sulfa is able to penetrate into exudate and abscessed tissue, as well as, penetrate the blood-brain-eye-placenta barrier. It is well absorbed orally with minimal effect on flora of the GI tract.
The safety of trimethoprim / sulfa during pregnancy is not clearly established. Reports indicate teratogenicity (cleft palate) in studies with rats. Therefore it is recommended that it not be given to pregnant rats.
Trimethoprim / sulfa is metabolized by the liver, and excreted during glomerular filtration and tubular secretion. Because sulfonamides are found to be excreted in breast milk it is advised to avoid giving trimethoprim / sulfa in rats that are nursing.
Blood: anemias, dyscrasias
Renal: crystalluria (sulfa bladder stones)
Skeletal: joint inflammation
Other: hypersensitivity/anaphylaxis, interference in tear production
Trimethoprim-sulfamethoxazole: 15 mg/kg to 30 mg/kg , PO , q12hrs to q24hrs 2
15 mg/kg to 30 mg/kg , PO ,IM, q12hrs 27
15 mg/kg , q12hrs, for 10-21 days 18
30 mg/kg , q12hrs , for 7-10 days 30
Trimethoprim-sulfadiazine: 30 mg/kg , SQ (*note: tissue necrosis may occur when given SQ), q12hrs to q24hrs 2
30 mg/kg , PO , SQ (*note: tissue necrosis may occur when given SQ), IM , q12hrs 1
*note* The initials DS stand for double strength on some of the brand names. One may see the vet prescribe this at a different frequency.
Posted on June 23, 2003, 14:38,
Last updated on February 10, 2015, 15:08
| Antimicrobial Agents