What routes can Cloxacillin be administered by?

Available routes: PO, IM, Intramammary.

Which species have cited Cloxacillin dosing data?

Cloxacillin dosing in the ExoticRx formulary covers 8 species: African Grey Parrot, Cat (Domestic), Dog (Domestic), Ferret, Great Horned Owl, Harris Hawk, Peregrine Falcon, Red-tailed Hawk.

Is Cloxacillin a controlled substance?

Cloxacillin is not federally scheduled in the US. Controlled-drug status differs by country — verify your local rules.

Cloxacillin

US brand names:Orbenin, Dry-Clox

Calculate dosage

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.

Cloxacillin is dosed at 10 mg/kg PO, IM, IV q6h in ferrets, per Besch-Williford CL. Biology and medicine of the ferret. Vet Clin North Am Small Anim Pract. 1987;17:1155-1183. — Source: Carpenter's Exotic Animal Formulary, 6th Ed, p.932 — Carpenter's Exotic Animal Formulary 6th ed, Table 11.1 (Antimicrobial Agents Used in Ferrets). Verify against current literature before clinical use.

Drug Class

Antibiotic

Routes

POIMIntramammary

Indications

Bacterial infection (general)Beta-lactamase-resistant penicillinstaphylococcal infectionStaphylococcal skin and soft tissue infections

Mechanism of Action

Inhibits bacterial cell wall synthesis by binding to PBPs. Resistant to staphylococcal penicillinase, providing targeted activity against penicillinase-producing Staphylococcus spp.

Side effects & warnings

Cross-allergenicity with other beta-lactams. GI upset common with oral administration. Primarily used for staphylococcal mastitis in cattle.

Evidence levels across 12 dose rules

Moderate×9Extrapolated×2Weak×1

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

Sample dosing (2 of 12 cited rules)

A dog/cat sample is shown here. Cited dosing for all 8 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
Cat (Domestic)	PO	20–40 mg/kg	q8h	Extrapolated	Papich/Saunders Handbook of Veterinary Drugs, 4th Ed, p.182Compilation only — we have not located an independent source that prints this figure.
Dog (Domestic)	PO	20–40 mg/kg	q8h	Extrapolated	Papich/Saunders Handbook of Veterinary Drugs, 4th Ed, p.182Compilation only — we have not located an independent source that prints this figure.

Backed by 5 published sourcesShow

· 391. Hawkins MG, Barron H, Speer BL, et al. Birds. In: Carpenter JW, eds. Exotic Animal Formulary, 4th ed., Elsevier Saunders, St. Louis, MO; 2013:183-437. — Source: Carpenter's Exotic Animal Formulary, 6th Ed, p.411 — RETRIEVED FINDING - CHANGE REQUIRED (retrieved 2026-08-19): Cloxacillin — | Narrow-spectrum β-lactamase-resistant penicillin; inactive against many gram-positive organisms¹⁰⁶ | 100-250 mg/kg PO, IM q24h³⁹¹ | Most species — Carpenter's Exotic Animal Formulary 6th ed, Table 5.1 (Antimicrobial Agents Used in Birds). DOSE/ROUTE/INTERVAL CONFIRMED. Indication is the defect.
· Avian Medicine: Principles and Application (Ritchie, Harrison & Harrison), p.811. Row as printed binds this dose to raptors on its own line: "Cloxacillin 100-250 mg/kg PO, IM q12-24h Most species, including raptors; recommended for treating".
· Besch-Williford CL. Biology and medicine of the ferret. Vet Clin North Am Small Anim Pract. 1987;17:1155-1183. — Source: Carpenter's Exotic Animal Formulary, 6th Ed, p.932 — Carpenter's Exotic Animal Formulary 6th ed, Table 11.1 (Antimicrobial Agents Used in Ferrets).
· Papich/Saunders Handbook of Veterinary Drugs, 4th Ed, p.182

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· Samour, Avian Medicine, 3rd Ed. (raptor formulary appendix), p.652. Row as printed binds this dose to raptors on its own line: "Cloxacillin Ampicox Syrup/ Raptors PO 250 mg/kg bid for 7-10 d Recommended in the treatment of infected".