Sourced from published veterinary references. Awaiting credentialed clinical reviewer — our editorial process.
Trimethoprim-Sulfamethoxazole is dosed at 15–30 mg/kg PO q12h in rabbits, per Plumb DC. Plumb's Veterinary Drug Handbook, 9th ed., Wiley Blackwell, Ames, IA; 2018. — 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.
May cause keratoconjunctivitis sicca (KCS) in dogs with prolonged use. Can cause bone marrow suppression. Avoid in animals with hepatic disease. Adequate hydration required.
Species with Trimethoprim-Sulfamethoxazole dosing data (33 dose rules)
Each ExoticRx dose rule is graded by the strength of its primary evidence — see the editorial process.
Sample dosing (2 of 33 cited rules)
A dog/cat sample is shown here. Cited dosing for all 21 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.
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.
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
· 802. Samour J. Pharmaceutics commonly used in avian medicine. In: Samour J, eds. Avian Medicine; Mosby, Philadelphia, PA; 2000:388-418. — 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).
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· Bodley K. Appendix 4. Drug Formulary. In: Vogelnest L, Portas T, eds. Current Therapy in Medicine of Australian Mammals; CSIRO Publishing, Clayton South, Vic; 2019:702-727.; Morrisey JK, Carpenter JW, et al. Formulary. In: Quesenberry KE, Orcutt CJ, Mans C, et al. Ferrets, Rabbits, and Rodents: Clinical Medicine and Surgery, 4th ed., Elsevier, St. Louis, MO; 2021:620-630. — Carpenter's 6th ed, Table 15.3 (Antimicrobial Therapy Used in Exotic Animals According to Site of Infection.a,b).
· Carpenter's Exotic Animal Formulary, 6th Ed — Carpenter's Exotic Animal Formulary 6th ed, Table 10.1 (Antimicrobial Agents Used in Rabbits.a).
· Carpenter's Exotic Animal Formulary, 6th Ed — Carpenter's Exotic Animal Formulary 6th ed, Table 5.4 (Antiparasitic Agents Used in Birds). — Carpenter's Exotic Animal Formulary 6th ed, Table 5.4 (Antiparasitic Agents Used in Birds).
· Dorrestein GM. Passerine and softbill therapeutics. Vet Clin North Am Exot Anim Pract. 2000;3:35-57. — Source: Carpenter's Exotic Animal Formulary, 6th Ed, p.422 doi:10.1016/s1094-9194(17)30094-4 — Carpenter's Exotic Animal Formulary 6th ed, Table 5.1 (Antimicrobial Agents Used in Birds.a).
· Gibbons PM, Klaphake E, Carpenter JW. Reptiles. In: Carpenter JW, ed. Exotic Animal Formulary. 4th ed. St. Louis: Elsevier; 2013:83-182. — Carpenter's Exotic Animal Formulary 6th ed, Table 4.1 (Antimicrobial Agents Used in Reptiles.a,b). | 2026-08-13 RE-ANCHOR: the supporting row is carpenter Table 4.4 (Antiparasitic Agents Used in Reptiles), "Trimethoprim-sulfonamides | 30 mg/kg PO q24 x2-14 days87,243 | Most species/coccidia, although this […]", with the block header "avoid potentiated sulfa drugs in cases of dehydration or renal dysfunction331". The previously cited Table 4.1 does NOT support this rule: its only 30 mg/kg PO trimethoprim-sulphonamide row is scoped "Bearded dragon" at q12h x14 days, and its trimethoprim/sulfamethoxazole row is "30 mg/kg IM q24h264 | Reticulated python". CORRECTION to this rule's own notes: mader printed p.1194 does NOT print "30 mg/kg, PO, IM, IV, q 24 h" - it prints "10-30 mg/kg PO q24h99 | Most species/maintain hydration" and, chelonian-specific, "30 mg/kg IM q24h x 2 days, then q48h311 | Tortoises/PD". No IV route, and the PO figure is a RANGE.
· Greenacre, C.B., Luna, G.L., and Morishita, T.M. (2018). Backyard poultry and waterfowl. In: Exotic Animal Formulary, 5e (ed. J.W. Carpenter), 377-432. St. Louis, Missouri: Elsevier. — Source: Greenacre & Morishita, Backyard Poultry Medicine and Surgery, 2nd Ed, p.589
· Hayes P. Diseases of chinchillas. In: Kirk's Current Veterinary Therapy: XIII Small Animal Practice. WB Saunders; 2000:1152-1157. — Plumb's Veterinary Drug Handbook, 10th Ed, p.1196
· 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.1195
· Hillyer EV, Brown SA. Ferrets. In: Birchard SJ, Sherding RG, eds. Saunders Manual of Small Animal Practice; WB Saunders, Philadelphia, PA; 1994:1317-1344. — Carpenter's Exotic Animal Formulary, 6th Ed, p.934
· Hoefer HL. Hedgehogs. Vet Clin North Am Small Anim Pract. — Carpenter's Exotic Animal Formulary 6th ed, Table 8.1 (Antimicrobial Agents Used in Hedgehogs).
· Meredith A. BSAVA Small Animal Formulary: Part B: Exotic Pets, British Small Animal Veterinary Association, Quedgeley, Gloucester, UK; 2015. / 130. Morrisey JK, Carpenter JW. Formulary. In: Quesenberry KE, Carpenter JW, eds. Ferrets, Rabbits, and Rodents: Clinical Medicine and Surgery, 4th ed., Elsevier, St. Louis, MO; 2021:620-630.
· Meredith A. BSAVA Small Animal Formulary: Part B: Exotic Pets, British Small Animal Veterinary Association, Quedgeley, Gloucester, UK; 2015.; Morrisey JK, Carpenter JW. Formulary. In: Quesenberry KE, Carpenter JW, eds. Ferrets, Rabbits, and Rodents: Clinical Medicine and Surgery, 4th ed., Elsevier, St. Louis, MO; 2021:620-630.
· Plumb DC. Plumb's Veterinary Drug Handbook, 9th ed., Wiley Blackwell, Ames, IA; 2018. — 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.
· Plumb's Veterinary Drug Handbook, 10th Ed, p.1196
· Plumb's Veterinary Drug Handbook, 10th ed (2023), Sulfa-/Trimethoprim, printed p.1195, DOGS — 'Superficial bacterial folliculitis (extra-label): 15 - 30 mg/kg PO twice daily.31' and 'Complicated UTI: 15 - 30 mg/kg PO every 12 hours32'. Superscript 31 = Hillier A, Lloyd DH, Weese JS, et al. Guidelines for the diagnosis and antimicrobial therapy of canine superficial bacterial folliculitis (ISCAID Antimicrobial Guidelines Working Group). Vet Dermatol. 2014;25(3):163-e43. Superscript 32 = Weese JS, Blondeau J, Boothe D, et al. ISCAID guidelines for the diagnosis and management of bacterial urinary tract infections in dogs and cats. Vet J. 2019;247:8-25.
· Plumb's Veterinary Drug Handbook, 10th ed (2023), p.1223 (Sulfa-/Trimethoprim, Dosages, CATS); corroborated by BSAVA Small Animal Formulary 10th Ed Part A p.419 'Dogs, Cats: 15-30 mg/kg p.o. q12h' — Plumb's Veterinary Drug Handbook, 10th ed, Sulfa-/Trimethoprim monograph, printed p.1196, CATS: "Bacterial cystitis (extra-label):. b) Complicated UTI: 15 - 30 mg/kg PO every 12 hours."; same monograph, printed p.1195: "Unless otherwise noted, doses are for combined sulfa-/trimethoprim."
· Plumb's Veterinary Drug Handbook, 9th Ed, p.1196 (Sulfa-/Trimethoprim, Dosages, HORSES) — 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.
· 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.1195