Which species have cited Trimethoprim dosing data?

Trimethoprim dosing in the ExoticRx formulary covers 6 species: African Grey Parrot, Ball Python, Bearded Dragon, Cat (Domestic), Dog (Domestic), Rabbit (Domestic).

Is Trimethoprim a controlled substance?

Trimethoprim is not federally scheduled in the US. Controlled-drug status differs by country — verify your local rules.

Trimethoprim

US brand names:Tribrissen(with sulfadiazine)

Calculate dosage

Sourced from published veterinary references. Awaiting credentialed clinical reviewer — our editorial process.

Trimethoprim is dosed at 15–25 mg/kg PO q24-48h in ball pythons, per Mader's Table 127.1, corpus p.1404 (printed 1194); Plumb's Sulfa-/Trimethoprim REPTILES, corpus p.1223, incl. 'may consider giving dose every other day after the second dose'. Verify against current literature before clinical use.

Drug Class

Antibiotic

Routes

POIV

Indications

Bacterial infections Bacterial infections (TMP-sulfa)Respiratory/urinary infectionsSusceptible infections (TMP-sulfa)Susceptible infections (with sulfonamide)

Mechanism of Action

Inhibits dihydrofolate reductase (DHFR) in folate synthesis pathway. Synergistic bactericidal activity when combined with sulfonamides.

Side effects & warnings

Almost always used in combination with a sulfonamide. Folate supplementation recommended in cats and during pregnancy. KCS risk in dogs.

Species with Trimethoprim dosing data (6 dose rules)

African Grey Parrot Ball Python Bearded Dragon Cat (Domestic)Dog (Domestic)Rabbit (Domestic)

Species references:All African Grey Parrot drugs All Ball Python drugs All Bearded Dragon drugs All Cat (Domestic) drugs All Dog (Domestic) drugs All Rabbit (Domestic) drugs

Evidence levels across 6 dose rules

Strong×2Weak×2Moderate×2

Each ExoticRx dose rule is graded by the strength of its primary evidence — see the editorial process.

Backed by 6 published sources

· Carpenter's Exotic Animal Formulary, 6th Ed
· Flammer K. Treatment of bacterial and mycotic diseases of the avian gastrointestinal tract. Proc North Am Vet Conf; 2002:851-852. — Verified against Carpenter's Exotic Animal Formulary, 6th Ed, p.422 (2026-08-01).
· 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).
· Mader's Table 127.1, corpus p.1404 (printed 1194); Plumb's Sulfa-/Trimethoprim REPTILES, corpus p.1223, incl. 'may consider giving dose every other day after the second dose'
· Plumb DC. Plumb’s Veterinary Drug Handbook, 9th — Verified against Carpenter's Exotic Animal Formulary, 6th Ed, p.845 (2026-08-01).
· Weese JS, Blondeau J, Boothe D, et al. International Society for Companion Animal Infectious Diseases (ISCAID) guidelines for the diagnosis and management of bacterial urinary tract infections in dogs and cats. Vet J. 2019;247:8-25. doi:10.1016/j.tvjl.2019.02.008 — Verified against Plumb's Veterinary Drug Handbook, 10th Ed, p.1223 (2026-08-01).

Sample dosing (2 of 6 cited rules)

A dog/cat sample is shown here. Cited dosing for all 6 species — reptiles, birds, pocket pets, livestock, and equine — is free on the per-species pages above. Pro adds the weight-based calculator for every species.

Species	Route	Dose	Frequency	Evidence	Source
Dog (Domestic)	PO	15–30 mg/kg	q12h	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).
Cat (Domestic)	PO	15–30 mg/kg	q12h	Strong	Weese JS, Blondeau J, Boothe D, et al. International Society for Companion Animal Infectious Diseases (ISCAID) guidelines for the diagnosis and management of bacterial urinary tract infections in dogs and cats. Vet J. 2019;247:8-25. doi:10.1016/j.tvjl.2019.02.008 — Verified against Plumb's Veterinary Drug Handbook, 10th Ed, p.1223 (2026-08-01).

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