Cephalexin for Cats

Cat · Felis catus · typical adult weight 2.50–7.00 kg

Cephalexin is dosed at 15–22 mg/kg PO q12h in cats, per Therios Chewable Tablets for Cats [Product Label; UK). Ceva Animal Health; 2018. — Verified against Plumb's Veterinary Drug Handbook, 10th Ed, p.263 (2026-08-01). — Plumb's 10th ed (held) printed p.234, Cephalexin monograph spanning p.234-236; page located 2026-08-05 from the book's own running heads, verified to name the drug in its body text. — SOURCE EDITION: Plumb's Veterinary Drug Handbook — ISBN 9781394172207, https://openlibrary.org/isbn/9781394172207. Cephalexin is used in cats for Feline acne, Dental abscess, Skin infections, UTI, Wound infections. Routes documented in cats: PO. A typical adult cat weighs 2.50–7.00 kg. ExoticRx lists 4 cited dose rules for Cephalexin in cats, drawn from published veterinary references. Verify against current literature before clinical use.

US trade names: Keflex

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	Duration	Indication	Evidence	Source
PO	15–22 mg/kg	q12h	14-21 days	Feline acne	Moderate	Therios Chewable Tablets for Cats [Product Label; UK). Ceva Animal Health; 2018. — Verified against Plumb's Veterinary Drug Handbook, 10th Ed, p.263 (2026-08-01). — Plumb's 10th ed (held) printed p.234, Cephalexin monograph spanning p.234-236; page located 2026-08-05 from the book's own running heads, verified to name the drug in its body text. — SOURCE EDITION: Plumb's Veterinary Drug Handbook — ISBN 9781394172207, https://openlibrary.org/isbn/9781394172207
PO	22–30 mg/kg	q8h	7-14 days	Dental abscess	Weak	BSAVA Small Animal Formulary, 10th ed, Part A (Canine and Feline) — Cefalexin (Cephalexin), DOSES, printed p.68 (corpus PDF p.84): "Cats: 15 mg/kg p.o. q8-12h ... Increased doses (20-30mg/kg p.o. q8-12h) should be used for […]" — SOURCE EDITION: BSAVA Small Animal Formulary, Part A — Canine and Feline — ISBN 9781910443705, https://openlibrary.org/isbn/9781910443705

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
15–20	PO	Papich Saunders Handbook of Veterinary Drugs, 4th edp.172	• 15-20 mg/kg q12h PO.

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 to PBPs. First-generation cephalosporin with good gram-positive coverage.

Side effects & warnings

May cause GI upset. Use with caution in penicillin-allergic animals (cross-reactivity). Not effective against Pseudomonas.

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

Frequently asked questions

What is the dose of Cephalexin for Cats?

Cephalexin dose ranges in cats, with cited source references: PO 15–22 mg/kg q12h; PO 22–30 mg/kg q8h; PO 15–30 mg/kg q8-12h; PO 15–25 mg/kg q12h. Reference ranges from cited sources — verify against current literature before clinical use.

How is Cephalexin administered in Cats?

Documented routes for Cephalexin in cats: PO.

How long is Cephalexin given in Cats?

Cited course lengths for Cephalexin in cats include: 14-21 days; 7-14 days. Duration depends on the indication — match it to the specific dose rule in the table above.

What conditions does Cephalexin treat in Cats?

Cephalexin is indicated in cats for: Feline acne, Dental abscess, Skin infections, UTI, Wound infections.

What are the side effects of Cephalexin in Cats?

These are general warnings for Cephalexin across species; consult the cat dosing table above for species-specific guidance. May cause GI upset. Use with caution in penicillin-allergic animals (cross-reactivity). Not effective against Pseudomonas.

Other Antibiotic drugs with cat dosing

Amikacin Amoxicillin Amoxicillin Injectable Amoxicillin-Clavulanate Ampicillin Azithromycin Bacitracin Carbenicillin Cefaclor Cefadroxil Cefazolin Cefdinir

Cephalexin dosing in other species

African Grey Parrots Dogs Domestic Pigeons Dwarf Hamsters Ferrets Gerbils Green-cheeked Conures Lovebirds

See all species for Cephalexin See all drugs for Cats

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