Sulfadimethoxine

Source: Wikipedia, the free encyclopedia.
Sulfadimethoxine
QP51BA01 (WHO)
Legal status
Legal status
  • AU: S4 (Prescription only)
  • US: ℞-only (by veterinarian)
Pharmacokinetic data
Bioavailability55–60%[2]
Elimination half-life13.1 hours in dogs[2]
Identifiers
  • 4-Amino-N-(2,6-dimethoxypyrimidin-4-yl)benzenesulfonamide
JSmol)
  • COc1cc(nc(n1)OC)NS(=O)(=O)c2ccc(cc2)N
  • InChI=1S/C12H14N4O4S/c1-19-11-7-10(14-12(15-11)20-2)16-21(17,18)9-5-3-8(13)4-6-9/h3-7H,13H2,1-2H3,(H,14,15,16) checkY
  • Key:ZZORFUFYDOWNEF-UHFFFAOYSA-N checkY
  (verify)

Sulfadimethoxine (or sulphadimethoxine, trade names Di-Methox or Albon) is a long-lasting

folic acid by acting as a competitive inhibitor against PABA. It is the most common drug prescribed to dogs who have coccidiosis.[4]

Mechanism

Like other sulfonamides, sulfadimethoxine is a

microbiocidal one (it prevents pathogen growth rather than killing them), and has the strongest effect in the beginning stages of an infection, when the pathogen is rapidly dividing. Since it is microbiostatic, sulfadimethoxine still requires the animal to still be able to mount an immune response to kill the pathogen.[6][3]

With ormetoprim

Sulfadimethoxine can either be given alone (such as under the commercial name Albon) or in combination with ormetoprim to as a "potentiated sulfonamide" to increase antimicrobial activity.

diaminopyridine, inhibiting dihydrofolate reductase, which is further along the pathway for synthesizing folic acid. Though the optimum ratio of sulfadimethoxine to ormetoprim has been found to be 20:1, it is sold pharmaceutically as a 5:1 mixture.[6]

Pharmacokinetics

On the left, a large amber bottle of labeled, "Albon (sulfadimethoxine): Oral suspension 5%". On the right, a bottle of Albon pills (125 mg, 200-count)
Suspension and bottle of pills of sulfadimethoxine, sold under the trade name Albon.

Sulfadimethoxine, like all sulfonamides, diffuses easily when it is in its unionized,

acetylate sulfadimethoxine in the liver to form acetylsulfadimethoxine, which is secreted in the bile. Dogs are the exception – since they are unable acetylate sulfonamides, they excrete sulfadimethoxine mostly unchanged in the urine (their inability to transform sulfadimethoxine also makes them more susceptible to negative side effects).[8][9][10]

Sulfadimethoxine has a relatively high solubility at the pH normally occurring in the kidneys, and is easily reabsorbed into the renal tubules, adding to its long half-life.[11][8] The use of sulfadimethoxine raises concerns that it will precipitate in the kidneys, leading to crystalluria. Though crystallization is not actually a common occurrence in veterinary medicine, it can be avoided entirely by adding a diaminopyrimidine such as ormetoprim.[11][6] Having the animal stay well-hydrated also is advised.[12]

Usage

Sulfadimethoxine is the only FDA-approved drug for treating intestinal coccidioisis in cats and dogs.[2] It is also used for:

It is also one of the only sulfonamides allowed for treating lactating dairy cattle (the others being sulfabromethazine and sulfathoxypyridazine).[6]

Contraindications

Sulfadimethoxine should not be used in ""chameleon"" species as the first therapeutic dose has been shown to lead in the animals mortality. ""Caution is warranted.""

Notes

  1. ^ a b "SulfaMed (sulfadimethoxine) Injection 40% for Animal Use". Drugs.com. Retrieved 2017-06-18.
  2. ^
    ISBN 9781118685907
    .
  3. ^ a b c d "ALBON – sulfadimethoxine suspension". DailyMed. US National Library of Medicine. 2014-05-21. Retrieved 2017-06-17.
  4. ^ Ward E (2008-12-08). "Coccidiosis in Dogs". Know Your Pet. VCA Hospitals. Retrieved 2017-06-18.
  5. ISBN 9780321918550
    .
  6. ^ a b c d e "Sulfonamides and Sulfonamide Combinations". Merck Veterinary Manual. Retrieved 2017-06-18.
  7. ^ Stowe CM (1965). "Chapter 33: The Sulfonamides". In Jones LM (ed.). Veterinary Pharmacology and Therapeutics. Ames, Iowa: Iowa State University Press.
  8. ^
    ISBN 9780470959640
    .
  9. ISBN 9781416028888
    .
  10. PMID 4972257
    .
  11. ^
    PMID 5499300.Closed access icon
  12. ^ PetCoach editorial team. "Sulfadimethoxine (Albon)". PetCoach.

This article incorporates text from the United States National Library of Medicine (ALBON sulfadimethoxine suspension), which is in the public domain.


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