What is Carbimazole used for?

Carbimazole is indicated for: Feline hyperthyroidism, Hyperthyroidism, Hyperthyroidism (rare in dogs).

Which species have cited Carbimazole dosing data?

Carbimazole dosing in the ExoticRx formulary covers 3 species: Cat (Domestic), Dog (Domestic), Guinea Pig.

Is Carbimazole a controlled substance?

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

Carbimazole

US brand names:Neo-Mercazole, Vidalta

Calculate dosage

Sourced from published veterinary references. Awaiting credentialed clinical reviewer — our editorial process.

Carbimazole is dosed at 1–2 mg/kg PO q24h in guinea pigs, per Ewringmann A, Gloeckner B. Leitsymptome bei Meerschweinchen, Chinchilla und Degu, Enke, Stuttgart, Germany; 2012. / Mayer J, Wagner R, Taeymans O. Advanced diagnostic approaches and current management of thyroid pathologies in guinea pigs. Vet Clin North Am Exot Anim Pract. 2010;13:509-523. — Source: Carpenter's Exotic Animal Formulary, 6th Ed, p.799 — Carpenter's Exotic Animal Formulary 6th ed, Table 9.7 (Miscellaneous Agents Used in Rodents). Verify against current literature before clinical use.

Drug Class

Endocrine

Routes

Indications

Feline hyperthyroidism Hyperthyroidism Hyperthyroidism (rare in dogs)

Mechanism of Action

Prodrug rapidly converted to methimazole, which inhibits thyroid peroxidase enzyme, blocking thyroid hormone synthesis.

Side effects & warnings

Similar side effects as methimazole. Monitor CBC (agranulocytosis risk), liver enzymes, renal function. Better GI tolerance than methimazole in some cats.

Species with Carbimazole dosing data (3 dose rules)

Cat (Domestic)Dog (Domestic)Guinea Pig

Species references:All Cat (Domestic) drugs All Dog (Domestic) drugs All Guinea Pig drugs

Evidence levels across 3 dose rules

Strong×1Weak×1Moderate×1

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

Sample dosing (2 of 3 cited rules)

A dog/cat sample is shown here. Cited dosing for all 3 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	2.5–5 mg per cat	q8-12h then q12h maintenance (immediate-release)	Strong	JFMS 2016; Plumb's Veterinary Drug Handbook — printed p.185.Compilation only — we have not located an independent source that prints this figure.
Dog (Domestic)	PO	10–15 mg per ANIMAL (NOT mg/kg)	q24h; adjust in 5 mg steps, do not split	Weak	Plumb's Veterinary Drug Handbook, 10th ed (2023) — Plumb's 10th ed printed p.184, Carbimazole monograph spanning p.184-185. — Plumb's 10th ed, Carbimazole monograph, printed p.184-185.Compilation only — we have not located an independent source that prints this figure.

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Backed by 3 published sourcesShow

· Ewringmann A, Gloeckner B. Leitsymptome bei Meerschweinchen, Chinchilla und Degu, Enke, Stuttgart, Germany; 2012. / Mayer J, Wagner R, Taeymans O. Advanced diagnostic approaches and current management of thyroid pathologies in guinea pigs. Vet Clin North Am Exot Anim Pract. 2010;13:509-523. — Source: Carpenter's Exotic Animal Formulary, 6th Ed, p.799 doi:10.1055/b-004-129947 — Carpenter's Exotic Animal Formulary 6th ed, Table 9.7 (Miscellaneous Agents Used in Rodents).
· JFMS 2016; Plumb's Veterinary Drug Handbook — printed p.185.
· Plumb's Veterinary Drug Handbook, 10th ed (2023) — Plumb's 10th ed printed p.184, Carbimazole monograph spanning p.184-185. — Plumb's 10th ed, Carbimazole monograph, printed p.184-185.

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