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Propylthiouracil

PTU

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

Drug Class

Endocrine

Routes

PO

Indications

Feline hyperthyroidism (historical use)Hyperthyroidism (pre-surgical)

Mechanism of Action

Inhibits thyroid peroxidase-mediated iodination and coupling reactions, and at high doses inhibits peripheral T4 to T3 conversion.

Side effects & warnings

Higher hepatotoxicity and immune-mediated reactions than methimazole. Not recommended in cats — methimazole preferred. Monitor CBC and liver function.

Species with Propylthiouracil dosing data (2 dose rules)

Cat (Domestic)Dog (Domestic)

Species references:All Cat (Domestic) drugsAll Dog (Domestic) drugs

Evidence levels across 2 dose rules

Weak×1Moderate×1

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

Backed by a published source

  • · Plumb's Veterinary Drug Handbook, 9th Ed

Sample dosing (2 of 2 cited rules)

A dog/cat sample is shown here. Cited dosing for all 2 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.

SpeciesRouteDoseFrequencyEvidenceSource
Dog (Domestic)PO5–10 mg/kgq12hWeakPlumb's Veterinary Drug Handbook, 9th Ed
Cat (Domestic)PO50 mg per catq12hModeratePlumb's Veterinary Drug Handbook, 9th Ed

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Calculate Dosage for Propylthiouracil