Propylthiouracil vs. Methimazole for Hyperthyroidism and Graves' Disease: Important Differences and Potential Risks.

Propylthiouracil

Methimazole

Summary for Propylthiouracil

Prescription only

Propylthiouracil is used to treat an overactive thyroid (also known as hyperthyroidism). The medication is typically used if you can't tolerate methimazole or are preparing to undergo surgery. It can cause serious, life-threatening liver damage with symptoms that you need to look out for (e.g., itchiness and upper right abdominal pain). Other possible side effects include nausea, rash, joint pain, and loss of taste. Propylthiouracil is a first-choice treatment option during pregnancy, but shouldn't be used after the first trimester due to the risk of harm to mothers and unborn babies.

Indications for Propylthiouracil

High thyroid hormone levels (hyperthyroidism) in people:
- With Graves’ disease or other medical conditions who can’t take methimazole, receive thyroid surgery, or radioactive iodine treatment
- Who are preparing to undergo thyroid surgery or radioactive iodine treatment

Pros and Cons for Propylthiouracil

Pros

Can be used during the first three months of pregnancy
First-choice medication for treating thyroid storm (life-threatening thyroid problem)
Available as a lower-cost generic

Cons

Must be taken three times a day
More serious side effects than methimazole, like potential liver damage
Can raise your chance of infections

Common Side Effects for Propylthiouracil

Nausea
Vomiting
Upper stomach pain or tenderness
Joint pain
Itching
Tingling sensation
Loss or change in taste
Loss of hair
Muscle pain
Headache
Nerve pain
Swelling (edema)
Dizziness

Warnings for Propylthiouracil

Liver damage
Harm to unborn babies
Weakened immune system
Low thyroid levels (hypothyroidism)
Blood vessel problems

Summary for Methimazole

Prescription only

Methimazole is an antithyroid medication. It's used to treat adults and children with hyperthyroidism (high thyroid hormone levels). This medication comes as a tablet. At the start, you usually take your dose by mouth 3 times a day. Then, your prescriber can work with you to find a dosing plan that works for you. Side effects can include rash, nausea, drowsiness, and headache. Although the brand name Tapazole is no longer sold, generic methimazole tablets are still available.

Indications for Methimazole

Hyperthyroidism related to:
- Graves’ disease
- Overactive thyroid nodules that can't be treated with thyroid surgery or radioactive iodine
- Preparation for thyroid surgery or radioactive iodine treatment

Pros and Cons for Methimazole

Pros

Maintenance dose usually taken once a day
Might work better at improving thyroid hormone levels than propylthiouracil (PTU)
Less risk of serious liver damage than other antithyroid medications

Cons

Need to get blood tests often to check thyroid hormone levels for dose adjustments
Might raise your risk of infection and easy bleeding
Not safe to take during the first trimester of pregnancy

Common Side Effects for Methimazole

Nausea (5-10%)
Vomiting (5-10%)
Stomach upset (5-10%)
Rash or hives (5-10%)
Itchiness (5-10%)

Warnings for Methimazole

Harm to an unborn baby during the first trimester of pregnancy
Very low white blood cell count
Liver damage
Hypothyroidism (low thyroid hormone levels)
Thickening of blood vessels (vasculitis)

Prices with our coupons for Propylthiouracil vs. Methimazole

Propylthiouracil90 tablets / 50mg

$26.76$57.18

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Methimazole30 tablets / 5mg

$11.17$22.38

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Propylthiouracil vs. Methimazole