Which species have cited Trimethoprim dosing data?

Trimethoprim dosing in the ExoticRx formulary covers 7 species: African Grey Parrot, Ball Python, Cat (Domestic), Dog (Domestic), Domestic Pigeon, Rabbit (Domestic), Zebra Finch.

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 15–30 mg/kg PO q12h in rabbits, per Plumb DC. Plumb’s Veterinary Drug Handbook, 9th — Carpenter's Exotic Animal Formulary 6th ed, Table 10.1 (Antimicrobial Agents Used in Rabbits.a). — EDITION NOTE 2026-08-06: this rule's Plumb's reference names the 9th edition, which is not held and was never consulted. The held copy is the 10th ed (2023). The Plumb's line was never confirmed against the held edition, so rely on it only as background; any other source named in this citation is unaffected. Verify against current literature before clinical use.

Drug Class

Antibiotic

Routes

POIV

Indications

Bacterial infectionsBacteriostatic gram-positive and gram-negative coverRespiratory/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 (7 dose rules)

African Grey Parrot Ball Python Cat (Domestic)Dog (Domestic)Domestic Pigeon Rabbit (Domestic)Zebra Finch

Species references:All African Grey Parrot drugs All Ball Python drugs All Cat (Domestic) drugs All Dog (Domestic) drugs All Domestic Pigeon drugs All Rabbit (Domestic) drugs All Zebra Finch drugs

Evidence levels across 7 dose rules

Weak×1Moderate×4Strong×2

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

Sample dosing (2 of 7 cited rules)

A dog/cat sample is shown here. Cited dosing for all 7 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. — Plumb's Veterinary Drug Handbook, 10th Ed, p.1195Compilation only — we have not located an independent source that prints this figure.
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 — Plumb's Veterinary Drug Handbook, 10th Ed, p.1196

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Backed by 7 published sourcesShow

· 236. Dorrestein GM. Studies on Pharmacokinetics of Some Antibacterial Agents in Homing Pigeons (Columba livia), Thesis: Utrecht University; 1986. | 240. Dorrestein GM. Antimicrobial drug use in companion birds. In: PrescottJF, Baggot JD, Walker RD, eds. Antimicrobial Therapy in Veterinary Medicine, 3rd ed., Iowa State University Press, Ames, IA; 2000:617-636. | 585. Marx KL, Roston MA. The Exotic Animal Drug Compendium: An International Formulary, Veterinary Learning Systems, Trenton, NJ; 1996. — Source: Carpenter's Exotic Animal Formulary, 6th Ed, p.422 — Carpenter's Exotic Animal Formulary 6th ed, Table 5.1 (Antimicrobial Agents Used in Birds.a).
· 236. Dorrestein GM. Studies on Pharmacokinetics of Some Antibacterial Agents in Homing Pigeons (Columba livia), Thesis: Utrecht University; 1986. — Source: Carpenter's Exotic Animal Formulary, 6th Ed, p.422 — Carpenter's Exotic Animal Formulary 6th ed, Table 5.1 (Antimicrobial Agents Used in Birds.a).
· Flammer K. Treatment of bacterial and mycotic diseases of the avian gastrointestinal tract. Proc North Am Vet Conf; 2002:851-852. — Carpenter's Exotic Animal Formulary 6th ed, Table 5.1 (Antimicrobial Agents Used in Birds.a).

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