Drugs A - Z

Propylthiouracil Oral tablet

It treats hyperthyroidism (where the thyroid gland makes too much hormone)

Generic Name: propylthiouracil

There is an FDA Alert for this drug. Click here to view it.

  • Severe liver injury and acute liver failure, in some cases requiring liver transplantation or resulting in death, reported in adult and pediatric patients.(See Hepatotoxicity under Cautions.)
  • Reserve propylthiouracil for patients who cannot tolerate methimazole and for whom radioactive iodine therapy or surgery are not appropriate for the management of hyperthyroidism. (See Hyperthyroidism under Uses.)
  • Propylthiouracil may be the treatment of choice when an antithyroid drug is indicated during or just prior to the first trimester of pregnancy because of the risk of fetal abnormalities associated with methimazole. (See Fetal/Neonatal Morbidity and also see Pregnancy under Cautions.)


FDA approved a REMS for propylthiouracil (ptu) to ensure that the benefits of a drug outweigh the risks. However, FDA later rescinded REMS requirements. See the FDA REMS page ([Web]) or the ASHP REMS Resource Center ([Web]).

What is this medicine?

PROPYLTHIOURACIL (PTU) (proe pill thye oh YOOR a sill) lowers the amount of thyroid hormone made by the thyroid gland. It treats hyperthyroidism (where the thyroid gland makes too much hormone). It also is used before thyroid surgery or radioactive iodine treatment.

What should I tell my health care provider before I take this medicine?

They need to know if you have any of these conditions:
  • blood disease
  • liver disease
  • an unusual or allergic reaction to propylthiouracil, other medicines, foods, dyes, or preservatives
  • pregnant or trying to get pregnant
  • breast-feeding

How should I use this medicine?

Take this medicine by mouth. Follow the directions on the prescription label. Take your doses at regular intervals. Do not take your medicine more often than directed. Do not stop taking except on your doctor's advice.

Talk to your pediatrician regarding the use of this medicine in children. While this drug may be prescribed for children as young as 6 years of age for selected conditions, precautions do apply.

What if I miss a dose?

If you miss a dose, take it as soon as you can. If it is almost time for your next dose, take only that dose. Do not take double or extra doses.

What may interact with this medicine?

  • amiodarone
  • digoxin
  • potassium iodide
  • propranolol
  • sodium iodide
  • theophylline
  • thyroid hormones, such as levothyroxine
  • warfarin

What should I watch for while using this medicine?

Visit your doctor or health care professional for regular checks on your progress. It may take time for your condition to improve. You will need tests to check your blood counts and to make sure your body is making the right amount of thyroid hormone.

If you are going to have surgery or dental surgery, tell your doctor, dentist, or health care professional that you are taking this medicine.

This medicine may lower your blood counts and lower your resistance to infection. Contact your doctor or health care professional if you have symptoms of an infection. Do not treat yourself for fever or sore throat. Check before receiving any vaccines.

While this medicine is sometimes used during pregnancy, side effects are possible in the unborn infant. Careful monitoring is needed. This medicine does pass to breast milk. Side effects in a breast-feeding infant are possible. Talk to your doctor or pharmacist for more information.

This medicine may cause serious liver problems. Contact your doctor or health care professional if you have flu-like symptoms, dark urine, light-colored stools, right upper belly pain, or yellowing of the eyes or skin.

What side effects may I notice from receiving this medicine?

Side effects that you should report to your doctor or health care professional as soon as possible:
  • dark urine
  • fever
  • general ill feeling or flu-like symptoms
  • goiter (enlarged thyroid gland causing swelling in the throat)
  • light-colored stools
  • loss of appetite
  • mouth sores
  • right upper belly pain
  • skin rash or itching (hives)
  • sore throat
  • swelling of the ankles or legs
  • unusual bleeding or bruising
  • unusual or sudden weight gain
  • unusually weak or tired
  • yellowing of skin or eyes

Side effects that usually do not require medical attention (report to your doctor or health care professional if they continue or are bothersome):

  • drowsiness
  • change or loss of taste
  • headache
  • joint or muscle aches
  • nausea
  • numbness or tingling in the hands or feet
  • upset stomach

Last Updated: April 08, 2010
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