What is Oxacillin used for?

Oxacillin is indicated for: Staphylococcal infections.

Which species have cited Oxacillin dosing data?

Oxacillin dosing in the ExoticRx formulary covers 1 species: Dog (Domestic).

Is Oxacillin a controlled substance?

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

What are the warnings or contraindications for Oxacillin?

Parenteral administration only. Interstitial nephritis possible. Not effective against MRSA. Hepatotoxicity rare.

What are the side effects of Oxacillin?

Reported side effects, adverse reactions, and contraindications for Oxacillin: Parenteral administration only. Interstitial nephritis possible. Not effective against MRSA. Hepatotoxicity rare.

How does Oxacillin work?

Penicillinase-resistant penicillin. Resists staphylococcal beta-lactamase. Narrow spectrum targeting methicillin-susceptible staphylococci.

Oxacillin

US brand names:Bactocill

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.

Oxacillin is dosed at 22–40 mg/kg IV q8h in dogs, per Plumb's Veterinary Drug Handbook, 10th ed (2023), printed p.964, Oxacillin, DOGS/CATS: 'Susceptible infections (extra-label): 22 - 40 mg/kg SC, IM, or IV every 8 hours'. Corroborated by Papich, Saunders Handbook of Veterinary Drugs, 5th ed, printed p.586, Oxacillin, Dogs and Cats: '22-40 mg/kg q8h PO.' — EDITION UNVERIFIABLE 2026-08-07: this citation names Papich 5th ed, which is NOT held. Its page locator does not resolve to a page naming this drug in the 4th ed (2016), so the reference cannot be confirmed against any copy available here. Treat the page number as unchecked and consult the 5th edition directly. Verify against current literature before clinical use.

Sample dosing (1 of 1 cited rule)

A dog/cat sample is shown here. Cited dosing for all 1 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
Dog (Domestic)	IV	22–40 mg/kg	q8h	Weak	Plumb's Veterinary Drug Handbook, 10th ed (2023), printed p.964, Oxacillin, DOGS/CATS: 'Susceptible infections (extra-label): 22 - 40 mg/kg SC, IM, or IV every 8 hours'. Corroborated by Papich, Saunders Handbook of Veterinary Drugs, 5th ed, printed p.586, Oxacillin, Dogs and Cats: '22-40 mg/kg q8h PO.' — EDITION UNVERIFIABLE 2026-08-07: this citation names Papich 5th ed, which is NOT held. Its page locator does not resolve to a page naming this drug in the 4th ed (2016), so the reference cannot be confirmed against any copy available here. Treat the page number as unchecked and consult the 5th edition directly.Compilation only — we have not located an independent source that prints this figure.

Backed by a published sourceShow

· Plumb's Veterinary Drug Handbook, 10th ed (2023), printed p.964, Oxacillin, DOGS/CATS: 'Susceptible infections (extra-label): 22 - 40 mg/kg SC, IM, or IV every 8 hours'. Corroborated by Papich, Saunders Handbook of Veterinary Drugs, 5th ed, printed p.586, Oxacillin, Dogs and Cats: '22-40 mg/kg q8h PO.' — EDITION UNVERIFIABLE 2026-08-07: this citation names Papich 5th ed, which is NOT held. Its page locator does not resolve to a page naming this drug in the 4th ed (2016), so the reference cannot be confirmed against any copy available here. Treat the page number as unchecked and consult the 5th edition directly.

Oxacillin

Drug Class

Routes

Indications

Mechanism of Action

Side effects & warnings

Species with Oxacillin dosing data (1 dose rule)

Evidence levels across 1 dose rule

Sample dosing (1 of 1 cited rule)

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Oxacillin

Drug Class

Routes

Indications

Mechanism of Action

Side effects & warnings

Species with Oxacillin dosing data (1 dose rule)

Evidence levels across 1 dose rule

Sample dosing (1 of 1 cited rule)

Upgrade for Full Details

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