Felimazole vs Thyronorm
A detailed comparison of Felimazole and Thyronorm for cats. Which is the better choice? We compare ingredients, dosing, price, and side effects.
Felimazole
Methimazole (thiamazole) sugar-coated tablets for feline hyperthyroidism. The original branded anti-thyroid medication for cats.
Thyronorm
Methimazole (thiamazole) flavoured tablets for feline hyperthyroidism. A newer-generation formulation designed to be more palatable for cats.
Save on Felimazole or Thyronorm at a UK pharmacy
UK registered pharmacies dispense the same prescription medications as your vet, often for less. Ask your vet for a written prescription, then fill it online.
Affiliate links to The Pharm Pet Co., a UK registered veterinary pharmacy. We may earn a small commission, at no extra cost to you. Always follow your vet's guidance on medication choice and dosing.
Side-by-Side Comparison
| Feature | Felimazole | Thyronorm |
|---|---|---|
| Active Ingredient | Thiamazole (Methimazole) | Thiamazole (Methimazole) |
| Form | Sugar-coated tablet | Flavoured tablet |
| Frequency | Once or twice daily | Once daily |
| Species | Cats | Cats |
| Price Range | £15–£35/box (100 tablets) | £15–£30/box (30 tablets) |
Key Differences
Active ingredient
Identical — both are thiamazole (methimazole). Same drug, different formulations.
Dosing
Thyronorm is designed for once-daily dosing; Felimazole often starts twice daily.
Strengths available
Thyronorm comes in 2.5, 5, and 10 mg; Felimazole in 1.25 and 2.5 mg.
Palatability
Thyronorm is specifically flavoured for cats; Felimazole is sugar-coated.
Cost
Similar overall cost — compare per-tablet prices at online online retailers for best value.
Pros & Cons
Felimazole
Pros
- The original — decades of clinical use
- Available in 1.25 mg and 2.5 mg strengths
- Sugar-coated — some cats accept it well
- Extensive safety data and vet familiarity
Cons
- Twice daily dosing often needed initially
- Sugar coating can be off-putting to some cats
- Difficult to split accurately for dose adjustments
- Side effects: vomiting, lethargy, facial itching
Thyronorm
Pros
- Designed for once-daily dosing
- Flavoured tablet — better acceptance by many cats
- Available in 2.5 mg, 5 mg, and 10 mg strengths
- Easier dose titration with more strength options
Cons
- Newer product — less long-term data
- Same side effects as Felimazole (same drug)
- May still need twice daily in some cats
- Prescription only
Compare Prices & Save
Both Felimazole and Thyronorm may be cheaper from a licensed online retailer than from your vet. Ask for a written prescription and compare prices.
Important: This comparison is for informational purposes only and is not veterinary advice. Always consult your vet before starting, stopping, or switching your pet's medication. Prices shown are typical UK ranges and may vary by product size, weight band, and retailer.
Alternative options to consider
Retailers we earn a commission from. It costs you nothing and never changes what we show.
The Pharm Pet Co. — Pet Pharmacy
UK online pet pharmacy. Flea, worm, prescription medications, supplements and pet food. Save vs vet prices.
Pet Care at Pharmacy2U
The UK's largest online pharmacy. Pet wormers, flea treatments, dental and joint care. Free delivery on orders over £30.
KatKin Fresh Cat Food
The UK's top-rated cat food. 100% fresh, human-quality meat, gently cooked and delivered frozen. Vet-formulated for every life stage.
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