What is Cloxacillin used for?

Cloxacillin is indicated for: Bacterial infection (general), Beta-lactamase-resistant penicillin, See source, staphylococcal infection, Staphylococcal skin and soft tissue infections.

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.

What are the warnings or contraindications for Cloxacillin?

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

What are the side effects of Cloxacillin?

Reported side effects, adverse reactions, and contraindications for Cloxacillin: Cross-allergenicity with other beta-lactams. GI upset common with oral administration. Primarily used for staphylococcal mastitis in cattle.

How does Cloxacillin work?

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

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.

Cloxacillin is dosed at 100–250 mg/kg PO, IM q24h in african grey parrots, per 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 — SOURCE EDITION: Carpenter's Exotic Animal Formulary — ISBN 9780323833929, https://openlibrary.org/isbn/9780323833929; Current Therapy in Avian Medicine and Surgery — ISBN 9781455746712, https://openlibrary.org/isbn/9781455746712 — 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), corpus p.411. DOSE/ROUTE/INTERVAL CONFIRMED. Indication is the defect.. Verify against current literature before clinical use.

Backed by 5 published sources

· 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 — SOURCE EDITION: Carpenter's Exotic Animal Formulary — ISBN 9780323833929, https://openlibrary.org/isbn/9780323833929; Current Therapy in Avian Medicine and Surgery — ISBN 9781455746712, https://openlibrary.org/isbn/9781455746712 — 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), corpus p.411. 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". Located by line-level extraction and then read on the page; the species binding is the row's own species column, not text proximity.

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	Verified against Papich/Saunders Handbook of Veterinary Drugs, 4th Ed, p.210 (2026-08-01). — LOCATOR CONVENTION 2026-08-07: the bare 'p.210' in this citation is the PDF index of the held scan, not the printed page. The PRINTED page is p.182; verified by finding the drug named there. If you are holding the book, turn to p.182. — SOURCE EDITION: Saunders Handbook of Veterinary Drugs — ISBN 9780323244855, https://openlibrary.org/isbn/9780323244855
Dog (Domestic)	PO	20–40 mg/kg	q8h	Extrapolated	Verified against Papich/Saunders Handbook of Veterinary Drugs, 4th Ed, p.210 (2026-08-01). — LOCATOR CONVENTION 2026-08-07: the bare 'p.210' in this citation is the PDF index of the held scan, not the printed page. The PRINTED page is p.182; verified by finding the drug named there. If you are holding the book, turn to p.182. — SOURCE EDITION: Saunders Handbook of Veterinary Drugs — ISBN 9780323244855,

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). 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

· 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". Located by line-level extraction and then read on the page; the species binding is the row's own species column, not text proximity.

· Verified against Papich/Saunders Handbook of Veterinary Drugs, 4th Ed, p.210 (2026-08-01). — LOCATOR CONVENTION 2026-08-07: the bare 'p.210' in this citation is the PDF index of the held scan, not the printed page. The PRINTED page is p.182; verified by finding the drug named there. If you are holding the book, turn to p.182. — SOURCE EDITION: Saunders Handbook of Veterinary Drugs — ISBN 9780323244855, https://openlibrary.org/isbn/9780323244855

Cloxacillin

Drug Class

Routes

Indications

Mechanism of Action

Side effects & warnings

Species with Cloxacillin dosing data (12 dose rules)

Evidence levels across 12 dose rules

Backed by 5 published sources

Sample dosing (2 of 12 cited rules)

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Cloxacillin

Drug Class

Routes

Indications

Mechanism of Action

Side effects & warnings

Species with Cloxacillin dosing data (12 dose rules)

Evidence levels across 12 dose rules

Backed by 5 published sources

Sample dosing (2 of 12 cited rules)

Upgrade for Full Details

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