Feline hyperthyroidism is one of the most common hormonal conditions in older cats — and methimazole is the most commonly prescribed treatment. If your vet has prescribed the transdermal gel version (applied to the inner ear flap), you've probably noticed that prices vary wildly between pharmacies. According to the Cornell Feline Health Center, hyperthyroidism affects roughly 10% of cats over age 10.

Compounded Methimazole vs. Tapazole (Pills)

Your vet has two main options for treating feline hyperthyroidism medically:

• Tapazole (methimazole tablets) — commercially available but requires pilling your cat twice daily. Many cats (and their owners) find this a daily battle.
• Compounded methimazole transdermal gel — rubbed onto the hairless inner skin of the ear flap. Same active ingredient, much easier administration. Only available through compounding pharmacies.

The compounded transdermal gel has become the preferred form for most cat owners for obvious reasons. But because it's compounded, prices are set by each pharmacy individually — and the range is substantial.

What Does Compounded Methimazole Actually Cost?

• Transdermal gel (2.5mg/0.1ml, 30-day supply): $20–$60/month — most common prescribed form
• Transdermal gel (5mg/0.1ml): $25–$75/month — higher concentration, same volume
• Oral liquid suspension: $20–$55/month
• Oral capsules (custom dose): $18–$50/month

The same methimazole transdermal gel can cost $22 at one pharmacy or $65 at another. The active ingredient and formulation are identical — the price reflects overhead, markup, and business model differences between pharmacies. See the full breakdown on our methimazole page.

What's Actually in the Gel? (Excipients Matter)

Compounded transdermal gels use a carrier base to help the medication absorb through skin. Commonly used bases include Pluronic lecithin organogel (PLO) and PCCA's Lipoderm.

Important: For cats specifically, xylitol-free formulations are critical — xylitol is toxic to cats and some commercial bases contain it. Always confirm with the pharmacy that their methimazole transdermal gel is xylitol-free.

How Often Does My Cat Need This Medication?

Methimazole for feline hyperthyroidism is typically a lifelong medication, dosed twice daily. On the expensive end ($60/month), that's $720/year; at the lower end ($25/month), it's $300/year — a difference of $420 annually for the exact same treatment. If you're also managing other feline conditions, check our compounded cyclosporine page and prednisolone page for other common cat medications.

How to Get the Best Price

The fastest way is to use CompoundingFinder.com — submit a free quote request specifying your cat's prescription details, and receive prices from multiple licensed compounding pharmacies within 1–2 business days. Make sure to note the concentration needed, quantity, and xylitol-free requirement. Not sure how compounding pharmacies work? Read our beginner's guide to compounding pharmacies.