METHIMAZOLE vs SYNTHROID

Independent side-by-side comparison.

Rated against independent regulatory sources·Last updated August 21, 2026·How we rate

Possible drug interaction. METHIMAZOLE and SYNTHROID are different prescription medicines. Combining or switching between them can cause interactions — talk to a pharmacist or prescriber before making changes. This page is not medical advice.

Attribute	METHIMAZOLE	SYNTHROID
Rating	New	70/100
Pharmacy pays	~$2.28 /30	~$1.83 /30
Type	RX	RX
Active ingredient	METHIMAZOLE	LEVOTHYROXINE SODIUM
Manufacturer	Aiping Pharm Inc	Abbvie
Dosage forms	Tablet	Tablet
Drug class	Thyroid Hormone Synthesis Inhibitor	L-Thyroxine
Boxed warning	None	Boxed warning
Half-life	—	about 6 to 7 days in adults with normal thyroid function
Treats	Goiter, Thyroid Crisis	Goiter, Myxedema, Thyroid Neoplasms

methimazole synthroid

Rating

New

70/100

Pharmacy pays

~$2.28 /30

~$1.83 /30

Type

Active ingredient

METHIMAZOLE

LEVOTHYROXINE SODIUM

Manufacturer

Aiping Pharm Inc

Abbvie

Dosage forms

Tablet

Drug class

Thyroid Hormone Synthesis Inhibitor

L-Thyroxine

Boxed warning

None

Boxed warning

Half-life

—

about 6 to 7 days in adults with normal thyroid function

Treats

Goiter, Thyroid Crisis

Goiter, Myxedema, Thyroid Neoplasms

Frequently asked questions

Which is cheaper, Methimazole or Synthroid?

Synthroid costs pharmacies less to acquire — about $1.83 vs $2.28 for a 30-count supply, per the CMS NADAC survey. That gap is in the pharmacy's cost of goods, not necessarily in what you pay: your price is set afterwards by your insurer and the pharmacy.

What is the difference between Methimazole and Synthroid?

Methimazole contains Methimazole, while Synthroid contains Levothyroxine Sodium — they have different active ingredients.

Ratings are based on FDA regulatory (recall-safety) data. This comparison is for general reference only — not medical advice. Always consult a licensed professional before choosing or switching a medication.