Ampicillin for Mice

Pocket Pet · Mus musculus · typical adult weight 0.02–0.04 kg

Ampicillin is dosed at 50–200 mg/kg PO q12h in mice, per 122. Meredith A. BSAVA Small Animal Formulary: Part B: Exotic Pets, British Small Animal Veterinary Association, Quedgeley, Gloucester, UK; 2015. — Mined from Carpenter's Exotic Animal Formulary, 6th Ed, p.770 (2026-08-01, PENDING REVIEW). Ampicillin is used in mice for Bacterial infection. Routes documented in mice: PO, SC, IM. A typical adult mouse weighs 0.02–0.04 kg. ExoticRx lists 2 cited dose rules for Ampicillin in mice, drawn from published veterinary references. Verify against current literature before clinical use.

US trade names: Polyflex

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
PO	50–200 mg/kg	q12h	Bacterial infection	Moderate	122. Meredith A. BSAVA Small Animal Formulary: Part B: Exotic Pets, British Small Animal Veterinary Association, Quedgeley, Gloucester, UK; 2015. — Mined from Carpenter's Exotic Animal Formulary, 6th Ed, p.770 (2026-08-01, PENDING REVIEW)
SC, IM	25 mg/kg	q12h	Bacterial infection	Moderate	122. Meredith A. BSAVA Small Animal Formulary: Part B: Exotic Pets, British Small Animal Veterinary Association, Quedgeley, Gloucester, UK; 2015. — Mined from Carpenter's Exotic Animal Formulary, 6th Ed, p.770 (2026-08-01, PENDING REVIEW)

Report an error in this entry

Need the exact dose for your patient?

These ranges are per kg. Enter your mouse's weight to get the precise dose and draw-up volume — unit and concentration math done for you.

Calculate for this mouse →

Mechanism of action

Inhibits bacterial cell wall synthesis by binding to penicillin-binding proteins. Broader spectrum than penicillin G with gram-negative coverage.

Side effects & warnings

CONTRAINDICATED in rabbits, guinea pigs, and hamsters (fatal dysbiosis). May cause GI upset. Cross-reactivity with other beta-lactams. IM injection may be painful.

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

Frequently asked questions

What is the dose of Ampicillin for Mice?

Ampicillin dose ranges in mice, with cited source references: PO 50–200 mg/kg q12h; SC, IM 25 mg/kg q12h. Reference ranges from cited sources — verify against current literature before clinical use.

How is Ampicillin administered in Mice?

Documented routes for Ampicillin in mice: PO, SC, IM.

What conditions does Ampicillin treat in Mice?

Ampicillin is indicated in mice for: Bacterial infection.

What are the side effects of Ampicillin in Mice?

These are general warnings for Ampicillin across species; consult the mouse dosing table above for species-specific guidance. CONTRAINDICATED in rabbits, guinea pigs, and hamsters (fatal dysbiosis). May cause GI upset. Cross-reactivity with other beta-lactams. IM injection may be painful.

Other Antibiotic drugs with mouse dosing

Amikacin Amoxicillin-Clavulanate Azithromycin Cefazolin Cephalexin Chloramphenicol Ciprofloxacin Clindamycin Doxycycline Enrofloxacin Erythromycin Gentamicin

Ampicillin dosing in other species

Ferrets Pet Rats African Grey Parrots Amazon Parrots Ball Pythons Bearded Dragons Blue-tongue Skinks Cats

See all species for Ampicillin See all drugs for Mice

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