Dog · Canis lupus familiaris · typical adult weight 2.00–80.00 kg
Trimethoprim is dosed at 15–30 mg/kg PO q12h in dogs, per Hillier A, Lloyd DH, Weese JS, et al. Guidelines for the diagnosis and antimicrobial therapy of canine superficial bacterial folliculitis (antimicrobial guidelines working group of the international society for companion animal infectious diseases). Vet Dermatol. 2014;25(3):163-e43. — Verified against Plumb's Veterinary Drug Handbook, 10th Ed, p.1222 (2026-08-01). — LOCATOR CONVENTION 2026-08-07: the bare 'p.1222' in this citation is the PDF index of the held scan, not the printed page. The PRINTED page is p.1195; verified by finding the drug named there. If you are holding the book, turn to p.1195. — SOURCE EDITION: Plumb's Veterinary Drug Handbook — ISBN 9781394172207, https://openlibrary.org/isbn/9781394172207. Trimethoprim is used in dogs for Susceptible infections (with sulfonamide). Routes documented in dogs: PO. A typical adult dog weighs 2.00–80.00 kg. ExoticRx lists 1 cited dose rule for Trimethoprim in dogs, drawn from published veterinary references. Verify against current literature before clinical use.
US trade names: Tribrissen
| Route | Dose | Frequency | Duration | Indication | Evidence | Source |
|---|---|---|---|---|---|---|
| PO | 15–30 mg/kg | q12h | 7-14 days | Susceptible infections (with sulfonamide) | Strong | Hillier A, Lloyd DH, Weese JS, et al. Guidelines for the diagnosis and antimicrobial therapy of canine superficial bacterial folliculitis (antimicrobial guidelines working group of the international society for companion animal infectious diseases). Vet Dermatol. 2014;25(3):163-e43. — Verified against Plumb's Veterinary Drug Handbook, 10th Ed, p.1222 (2026-08-01). — LOCATOR CONVENTION 2026-08-07: the bare 'p.1222' in this citation is the PDF index of the held scan, not the printed page. The PRINTED page is p.1195; verified by finding the drug named there. If you are holding the book, turn to p.1195. — SOURCE EDITION: Plumb's Veterinary Drug Handbook — ISBN 9781394172207, https://openlibrary.org/isbn/9781394172207 |
Every held source for this drug and species, as printed. Where they differ, both are shown — the choice is yours, not ours.
| Dose (mg/kg) | Route | Source | As printed |
|---|---|---|---|
| 15–30 | PO | BSAVA Small Animal Formulary, 10th ed — Part A (Canine and Feline)p.435 | 15-30 mg/kg p.o. q12h. 30 mg/kg s.c. q24h. |
| 30 | SC | BSAVA Small Animal Formulary, 10th ed — Part A (Canine and Feline)p.435 | 15-30 mg/kg p.o. q12h. 30 mg/kg s.c. q24h. |
| 15 | PO | Papich Saunders Handbook of Veterinary Drugs, 4th edp.848 | • 15 mg/kg q12h PO or 30 mg/kg q12-24h PO. |
| 30 | PO | Papich Saunders Handbook of Veterinary Drugs, 4th edp.848 | • 15 mg/kg q12h PO or 30 mg/kg q12-24h PO. |
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These ranges are per kg. Enter your dog's weight to get the precise dose and draw-up volume — unit and concentration math done for you.
Inhibits dihydrofolate reductase (DHFR) in folate synthesis pathway. Synergistic bactericidal activity when combined with sulfonamides.
Almost always used in combination with a sulfonamide. Folate supplementation recommended in cats and during pregnancy. KCS risk in dogs.
Species-specific contraindications and adverse-reaction reports for dogs may differ from canine / feline reference data — consult the primary citations listed with each rule.
Trimethoprim dose range in dogs, with cited source references: PO 15–30 mg/kg q12h. Reference ranges from cited sources — verify against current literature before clinical use.
Documented routes for Trimethoprim in dogs: PO.
Cited course lengths for Trimethoprim in dogs include: 7-14 days. Duration depends on the indication — match it to the specific dose rule in the table above.
Trimethoprim is indicated in dogs for: Susceptible infections (with sulfonamide).
These are general warnings for Trimethoprim across species; consult the dog dosing table above for species-specific guidance. Almost always used in combination with a sulfonamide. Folate supplementation recommended in cats and during pregnancy. KCS risk in dogs.
Why a species-specific page? Trimethoprim pharmacokinetics differ across species: dose ranges, intervals, and route preferences are not interchangeable. Cross-extrapolation from canine doses is unsafe in dogs — the rules above are the citations specific to this species, not generic recommendations.
Sourced from published veterinary references; awaiting credentialed clinical reviewer. See our editorial process. Reference only — not veterinary advice.
| 30 |
| IV |
| Papich Saunders Handbook of Veterinary Drugs, 4th edp.850 |
| • 30 mg/kg q12h IV (see “Instructions for Use” section for preparation of IV |
Figures are transcribed from the cited page or table of each held edition and are shown for reference only. They are not dose recommendations, they do not feed the calculator, and none has been reviewed by a veterinarian.