Contraindicated in Rabbit, Guinea Pig, Chinchilla, Hamster, Degu
Rabbit: Oral beta-lactams cause fatal dysbiosis in rabbitsOral amoxicillin (and other oral beta-lactams) selectively destroy gram-positive hindgut flora in rabbits, allowing Clostridium spiroforme overgrowth and fatal enterotoxemia. Never administer oral beta-lactams to rabbits. Parenteral administration carries a lower risk than the oral route, but is not established as safe in rabbits.
Guinea Pig: Oral beta-lactams cause fatal dysbiosis in guinea pigsOral amoxicillin reliably causes Clostridium difficile-mediated fatal enterotoxemia in guinea pigs. Same mechanism as in rabbits. Parenteral administration carries a lower risk than the oral route; parenteral ceftiofur specifically has been given to guinea pigs and chinchillas without adverse effect.
Chinchilla: Oral beta-lactams cause fatal dysbiosis in chinchillasChinchillas are hindgut fermenters with the same flora dependence as rabbits and guinea pigs. Oral penicillins and oral cephalosporins trigger Clostridium overgrowth and fatal enterotoxemia. Never give oral beta-lactams; parenteral routes and trimethoprim-sulfa, fluoroquinolones, or chloramphenicol are the safer choices.
Hamster: Oral beta-lactams cause fatal enterocolitis in hamstersHamsters are exquisitely susceptible to antibiotic-associated Clostridium difficile enterocolitis — the hamster is the classic laboratory model for it. Oral penicillins and cephalosporins are reliably fatal. Never administer oral beta-lactams.
Degu: Oral beta-lactams risk fatal dysbiosis in degusDegus are caviomorph hindgut fermenters closely related to chinchillas and guinea pigs. Degu-specific data is limited, so this warning is extrapolated from those related hystricomorphs — but the shared physiology makes oral beta-lactam enterotoxemia the expected outcome. Treat as contraindicated; use the safer alternatives.
Sourced from published veterinary references. Awaiting credentialed clinical reviewer — our editorial process.
Penicillin G procaine is dosed at 40000 IU/kg SC, IM q24h in african pygmy hedgehogs, per 29. Isenbügel E, Baumgartner R. Diseases of the hedgehog. In: Fowler M, eds. Zoo and Wild Animal Medicine: Current Therapy, 3rd ed., WB Saunders, Philadelphia, PA; 1993:294-302. | 52. Morrisey JK, Carpenter JW, et al. Formulary. In: Quesenberry Q, Orcutt C, Mans C, et al. Ferrets, Rabbits and Rodents: Clinical Medicine and Surgery, 4th ed., Elsevier, St. Louis, MO; 2021:620-630. — Mined from Carpenter's Exotic Animal Formulary, 6th Ed, p.734 (2026-08-01, PENDING REVIEW). Verify against current literature before clinical use.
Added 2026-08-04 by the book-verification programme. Drug identity independently confirmed as distinct from every existing formulary entry. Source opened: Carpenter's Exotic Animal Formulary 6e — corpus book 'carpenter' p.734 (hedgehog antimicrobial table), refs 29 = Isenbügel & Baumgartner (carpenter refs p.761) and 52 = Morrisey & Carpenter Formulary (carpenter refs p.764) — exactly the draft's two citations. . Class as printed in source: Natural (benzyl) penicillin — poorly-soluble procaine salt, depot/repository IM formulation
Species with Penicillin G procaine dosing data (1 dose rule)
Each ExoticRx dose rule is graded by the strength of its primary evidence — see the editorial process.
Backed by a published source
· 29. Isenbügel E, Baumgartner R. Diseases of the hedgehog. In: Fowler M, eds. Zoo and Wild Animal Medicine: Current Therapy, 3rd ed., WB Saunders, Philadelphia, PA; 1993:294-302. | 52. Morrisey JK, Carpenter JW, et al. Formulary. In: Quesenberry Q, Orcutt C, Mans C, et al. Ferrets, Rabbits and Rodents: Clinical Medicine and Surgery, 4th ed., Elsevier, St. Louis, MO; 2021:620-630. — Mined from Carpenter's Exotic Animal Formulary, 6th Ed, p.734 (2026-08-01, PENDING REVIEW)
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