Penicillin G for Rabbits

Pocket Pet · Oryctolagus cuniculus · typical adult weight 1.00–5.00 kg

Penicillin G is dosed at 40000 U/kg SC q7d x 3 treatments in rabbits, per GelattKN. Exotic animal ophthalmology. In: GelattKN, eds. Essentials of Veterinary Ophthalmology; Blackwell, Oxford, UK; 2005:413-438. — Source: Carpenter's Exotic Animal Formulary, 6th Ed, p.874 — Carpenter's Exotic Animal Formulary 6th ed, Table 10.9 (Ophthalmologic Agents Used in Rabbits). The copy held is an ebook conversion with no printed page numbers, so the table — not the page — is the citable location. — SOURCE EDITION: Carpenter's Exotic Animal Formulary — ISBN 9780323833929, https://openlibrary.org/isbn/9780323833929; Veterinary Ophthalmology — ISBN 9781119441830, https://openlibrary.org/isbn/9781119441830. Penicillin G is used in rabbits for Treponema cuniculi-induced blepharitis (rabbit syphilis). Routes documented in rabbits: SC. A typical adult rabbit weighs 1.00–5.00 kg. ExoticRx lists 1 cited dose rule for Penicillin G in rabbits, drawn from published veterinary references. Verify against current literature before clinical use.

US trade names: Pen-G, Crysticillin

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.

Dose ranges

Route	Dose	Frequency	Indication	Evidence	Source
SC	40000 U/kg	q7d x 3 treatments	Treponema cuniculi-induced blepharitis (rabbit syphilis)	Moderate	GelattKN. Exotic animal ophthalmology. In: GelattKN, eds. Essentials of Veterinary Ophthalmology; Blackwell, Oxford, UK; 2005:413-438. — Source: Carpenter's Exotic Animal Formulary, 6th Ed, p.874 — Carpenter's Exotic Animal Formulary 6th ed, Table 10.9 (Ophthalmologic Agents Used in Rabbits). The copy held is an ebook conversion with no printed page numbers, so the table — not the page — is the citable location. — SOURCE EDITION: Carpenter's Exotic Animal Formulary — ISBN 9780323833929, https://openlibrary.org/isbn/9780323833929; Veterinary Ophthalmology — ISBN 9781119441830, https://openlibrary.org/isbn/9781119441830

What each reference text prints

Every held source for this drug and species, as printed. Where they differ, both are shown — the choice is yours, not ours.

Printed doses in mg/kg for this drug and species, by source
Dose (mg/kg)	Route	Source	As printed
40	SC	BSAVA Small Animal Formulary, 10th ed — Part B (Exotic Pets)p.243	7 days for 3 doses for Treponema cuniculi; other infections 40 mg/kg s.c. q12-24h a; Rats (not procaine): 22 mg/kg s.c., i.m. q24h
22	SC	BSAVA Small Animal Formulary, 10th ed — Part B (Exotic Pets)p.243	er infections 40 mg/kg s.c. q12-24h a; Rats (not procaine): 22 mg/kg s.c., i.m. q24h

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.

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Mechanism of action

Inhibits bacterial cell wall synthesis by binding PBPs. Bactericidal. Narrow spectrum: primarily gram-positive and some anaerobes.

Side effects & warnings

CONTRAINDICATED in rabbits, guinea pigs, hamsters. Hypersensitivity reactions. Procaine form: IM/SC only (never IV). Potassium form: slow IV only. Pain at injection site.

Species-specific contraindications and adverse-reaction reports for rabbits may differ from canine / feline reference data — consult the primary citations listed with each rule.

Frequently asked questions

What is the dose of Penicillin G for Rabbits?

Penicillin G dose range in rabbits, with cited source references: SC 40000 U/kg q7d x 3 treatments. Reference ranges from cited sources — verify against current literature before clinical use.

How is Penicillin G administered in Rabbits?

Documented routes for Penicillin G in rabbits: SC.

What conditions does Penicillin G treat in Rabbits?

Penicillin G is indicated in rabbits for: Treponema cuniculi-induced blepharitis (rabbit syphilis).

What are the side effects of Penicillin G in Rabbits?

These are general warnings for Penicillin G across species; consult the rabbit dosing table above for species-specific guidance. CONTRAINDICATED in rabbits, guinea pigs, hamsters. Hypersensitivity reactions. Procaine form: IM/SC only (never IV). Potassium form: slow IV only. Pain at injection site.

Other Antibiotic drugs with rabbit dosing

Amikacin Azithromycin Cefazolin Cefotaxime Ceftazidime Ceftiofur Cephalexin Chloramphenicol Chlortetracycline Ciprofloxacin Difloxacin Doxycycline

Penicillin G dosing in other species

Ferrets Pet Rats Sugar Gliders Goats

See all species for Penicillin G See all drugs for Rabbits

Why a species-specific page? Penicillin G pharmacokinetics differ across species: dose ranges, intervals, and route preferences are not interchangeable. Cross-extrapolation from canine doses is unsafe in rabbits — 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.