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Sulfadimethoxine/Ormetoprim

Prescription
Potentiated Sulfonamide Antibiotic
Last reviewed 22 Apr 2026 · PetCare.AI Editorial Team
Species
Dog, Cat
Brands
1 available
Formulations
1

Mechanism of action

Synergistic combination: sulfadimethoxine inhibits DHPS and ormetoprim inhibits DHFR (same sequential folate blockade as TMP-sulfa). Long half-life allows once-daily dosing. FDA-approved for dogs.

At a glance

Class
Potentiated Sulfonamide Antibiotic
Schedule
Prescription
Storage
Store at room temperature below 30°C

Dosing

🐕

Dog

FDA-approved for canine skin infections and UTIs
Dose
55 mg/kg
Route
PO
Frequency
q24h (after loading)
🐈

Cat

Sulfadimethoxine alone (Albon) is used in cats for coccidiosis at different dose
Dose
Route
N, A
Frequency
N/A
Educational reference only
This information is provided for educational purposes and is not a substitute for professional veterinary advice, diagnosis, or treatment. Always consult a qualified veterinarian before administering any medication to your pet. Find a vet near you →

Formulations

💊

Other — 1

Strength

Storage

Store at room temperature below 30°C

Safety

Monitoring parameters

Schirmer tear testCBCUrinalysis (hydration)Hepatic enzymesThyroid function (chronic)
Educational reference only
This information is provided for educational purposes and is not a substitute for professional veterinary advice, diagnosis, or treatment. Always consult a qualified veterinarian before administering any medication to your pet. Find a vet near you →

Interactions

No documented interactions.

Brands

United States

Primor

FAQs

Frequently asked questions

What is Sulfadimethoxine/Ormetoprim?
Sulfadimethoxine/Ormetoprim is a potentiated sulfonamide antibiotic used in pets. Synergistic combination: sulfadimethoxine inhibits DHPS and ormetoprim inhibits DHFR (same sequential folate blockade as TMP-sulfa). Long half-life allows once-daily dosing. FDA-approved for dogs.
What is Sulfadimethoxine/Ormetoprim used for in pets?
Sulfadimethoxine/Ormetoprim is used in veterinary medicine for: FDA-approved for canine skin infections and UTIs; Sulfadimethoxine alone (Albon) is used in cats for coccidiosis at different dose.
What is the Sulfadimethoxine/Ormetoprim dose for dogs?
For dogs, Sulfadimethoxine/Ormetoprim is typically dosed as follows — FDA-approved for canine skin infections and UTIs: 55 mg/kg PO q24h (after loading). Always consult your veterinarian for a dose tailored to your pet's weight, age, and condition.
What is the Sulfadimethoxine/Ormetoprim dose for cats?
For cats, Sulfadimethoxine/Ormetoprim is typically dosed as follows — Sulfadimethoxine alone (Albon) is used in cats for coccidiosis at different dose: undefined undefined N/A N/A. Always consult your veterinarian for a dose tailored to your pet's weight, age, and condition.
Does Sulfadimethoxine/Ormetoprim need a prescription?
Yes. Sulfadimethoxine/Ormetoprim is a prescription medication and should only be administered under veterinary supervision.
Educational reference only
This information is provided for educational purposes and is not a substitute for professional veterinary advice, diagnosis, or treatment. Always consult a qualified veterinarian before administering any medication to your pet. Find a vet near you →

References

References

The PetCare.AI drug reference is built from 13 authoritative sources cited across 580 drug monographs.

Textbooks & handbooks — 5

  • Plumb's Veterinary Drug Handbook
  • Withrow & MacEwen's Small Animal Clinical Oncology
  • Merck Veterinary Manual
  • NRC Nutrient Requirements of Dogs and Cats
  • Veterinary Pharmacology and Therapeutics (Riviere & Papich)

Clinical guidelines & consensus — 4

  • ASPCA Animal Poison Control Center Guidelines
  • AAHA Diabetes Management Guidelines
  • ASPCA Poison Control Guidelines
  • RECOVER CPR Guidelines

Journals & peer-reviewed studies — 2

  • EPIC Study (J Vet Intern Med 2016)
  • JVIM FAT CAT Study

Regulatory & approvals — 1

  • CDSCO Veterinary Drug Approval Registry (1969–2026)

Databases — 1

  • Washington State University VCPL MDR1 Database

Related medicines

Other medicines in the same class (Potentiated Sulfonamide Antibiotic).

Sulfa-Trimethoprim (TMP-Sulfa)
Rx
Sequential inhibition of folate synthesis: sulfonamide inhibits dihydropteroate synthase (DHPS) and trimethoprim inhibits dihydrofolate reductase (DHFR). Combined, they are synergistically bactericidal despite each being bacteriostatic alone. 1:5 TMP:sulfa ratio.
dogcat
Trimethoprim-Sulfamethoxazole
Rx
Sequential blockade of folate synthesis — sulfamethoxazole inhibits dihydropteroate synthase, trimethoprim inhibits dihydrofolate reductase
dogcat
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