Sulfadiazine/Trimethoprim and Sulfamethoxazole/Trimethoprim
Also known as: Co-trimoxazole, Tribrissen, Bactrim, Septra, Tucoprim, Uniprim, Di-Biotic, Cotrim, Sulfatrim, Trivetrin, Borgal
**Important Guidance for Pet Owners:** - **Hydration is Crucial:** Ensure your pet has free access to plenty of fresh water at all times while on this medication. Dehydration can lead to drug crystals forming in the kidneys or urine. - **Watch the Eyes (Dogs):** This medication can decrease tear production, leading to a condition called "dry eye" (keratoconjunctivitis sicca). Contact your veterinarian immediately if you notice your dog squinting, rubbing their eyes, redness, or thick yellow/green eye discharge. - **Allergic Reactions:** Doberman Pinschers and some large breed dogs are more prone to allergic reactions. Stop the medication and call your vet if you notice facial swelling, hives, unexplained fever, joint stiffness/limping, or yellowing of the eyes/gums. - **Administration:** Can be given with or without food. If using the liquid oral suspension, **shake it thoroughly** before drawing up each dose. The liquid does not need to be refrigerated. - **Finish the Course:** Always complete the entire prescription as directed by your veterinarian, even if your pet seems completely better, to prevent antibiotic resistance.
Dosage must be set by your veterinarian for your specific pet. Never give human medication or another pet’s prescription without veterinary guidance.
What it is used for
- UTI
- UTI, soft tissue infections
- Susceptible infections
- Toxoplasmosis
- Bacterial UTI
- Susceptible infections
- Coccidiosis
- Susceptible infections
- Susceptible infections
- Susceptible infections (Calves)
- Respiratory tract infections
- Susceptible infections (Foals)
- Susceptible infections
- Susceptible infections
How it is given
Possible side effects
- Dogs: Keratoconjunctivitis sicca (KCS/dry eye - potentially irreversible)
- Dogs: Hypersensitivity reactions (Type 1 anaphylaxis or Type 3 serum sickness, polyarthritis, urticaria, facial swelling)
- Dogs: Acute neutrophilic hepatitis with icterus, idiosyncratic hepatic necrosis
- Dogs: Vomiting, anorexia, diarrhea
- Dogs: Hemolytic anemia, agranulocytosis
- Dogs: Hypothyroidism (with extended therapy)
- Dogs: Crystalluria, hematuria, polyuria, polydipsia
- Cats: Anorexia, crystalluria, hematuria, leukopenias, anemias
- Horses: Transient pruritus (after IV injection), diarrhea, hypersensitivity, hematologic effects
- Injection site reactions: Swelling, pain, tissue damage (IM, SC, or extravasation)
Cautions & contraindications
- Hypersensitivity to sulfonamides, thiazides, or sulfonylurea agents
- Severe renal or hepatic impairment
- Doberman pinschers (highly susceptible to immune complex disease)
- Marked blood dyscrasias
- Animals intended for food (in the USA/certain jurisdictions)
- Use with caution in patients with pre-existing hepatic or renal disease. Because of its potential for crystallization in the urine, avoid use in dogs known to have uroliths, at increased risk for developing uroliths, or those with highly concentrated (dehydrated) or acidic urine. Potentially teratogenic (cleft palate reported); weigh risk vs. benefit in pregnant animals. Use with caution in nursing animals as sulfonamides are excreted in milk and may cause kernicterus in neonates.
Drug interactions
- Amantadine: May cause toxic delirium (reported in humans)
- Antacids: May decrease the bioavailability of sulfonamides if administered concurrently
- Cyclosporine: May increase the risk of nephrotoxicity
- Digoxin: May increase digoxin levels
- Diuretics, Thiazide: May increase risk for thrombocytopenia
- Hypoglycemic agents, oral: May potentiate hypoglycemic effects
- Methotrexate: May displace from plasma proteins and increase risk for toxic effects; can also interfere with MTX assays
- Phenytoin: May increase half-life of phenytoin
- Tricyclic antidepressants: May decrease efficacy of the antidepressant
- Warfarin: May prolong INR/PT and increase bleeding risk
Frequently asked questions
What is Sulfadiazine/Trimethoprim and Sulfamethoxazole/Trimethoprim used for in pets?
**Important Guidance for Pet Owners:** - **Hydration is Crucial:** Ensure your pet has free access to plenty of fresh water at all times while on this medication. Dehydration can lead to drug crystals forming in the kidneys or urine. - **Watch the Eyes (Dogs):** This medication can decrease tear production, leading to a condition called "dry eye" (keratoconjunctivitis sicca). Contact your veterinarian immediately if you notice your dog squinting, rubbing their eyes, redness, or thick yellow/green eye discharge. - **Allergic Reactions:** Doberman Pinschers and some large breed dogs are more prone to allergic reactions. Stop the medication and call your vet if you notice facial swelling, hives, unexplained fever, joint stiffness/limping, or yellowing of the eyes/gums. - **Administration:** Can be given with or without food. If using the liquid oral suspension, **shake it thoroughly** before drawing up each dose. The liquid does not need to be refrigerated. - **Finish the Course:** Always complete the entire prescription as directed by your veterinarian, even if your pet seems completely better, to prevent antibiotic resistance.
Is Sulfadiazine/Trimethoprim and Sulfamethoxazole/Trimethoprim safe for my pet?
Dosage must be set by your veterinarian for your specific pet. Never give human medication or another pet’s prescription without veterinary guidance.
This article is for general education and is not a substitute for professional veterinary advice. If your pet is unwell, please consult a veterinarian.
Worried about your pet?
Peqaboo’s AI helps you track symptoms, understand lab reports, and know when to see a vet.
Get the Peqaboo app