Question 1

What is Propylthiouracil used for?

Accepted Answer

Propylthiouracil is indicated for: Feline hyperthyroidism (historical use), Hyperthyroidism (pre-surgical).

Question 2

What routes can Propylthiouracil be administered by?

Accepted Answer

Available routes: PO.

Question 3

Which species have cited Propylthiouracil dosing data?

Accepted Answer

Propylthiouracil dosing in the ExoticRx formulary covers 2 species: Cat (Domestic), Dog (Domestic).

Question 4

Is Propylthiouracil a controlled substance?

Accepted Answer

Propylthiouracil is not federally scheduled as a controlled substance, but is veterinary prescription only in most jurisdictions.

Question 5

What are the warnings or contraindications for Propylthiouracil?

Accepted Answer

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

Question 6

What are the side effects of Propylthiouracil?

Accepted Answer

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

Question 7

How does Propylthiouracil work?

Accepted Answer

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

Species	Route	Dose	Frequency	Evidence	Source
Dog (Domestic)	PO	5–10 mg/kg	q12h	Weak	Plumb's Veterinary Drug Handbook, 9th Ed
Cat (Domestic)	PO	50 mg per cat	q12h	Moderate	Plumb's Veterinary Drug Handbook, 9th Ed

Propylthiouracil

Drug Class

Routes

Indications

Mechanism of Action

Side effects & warnings

Species with Propylthiouracil dosing data (2 dose rules)

Evidence levels across 2 dose rules

Backed by a published primary source

Sample dosing (2 of 2 cited rules)

Upgrade for Full Details