Propylthiouracil is used to treat hyperthyroidism (overactive thyroid), Graves' disease, or toxic goiter (enlarged thyroid). propylthiouracil is sometimes given to control symptoms just before you undergo thyroid surgery or treatment with radioactive iodine.

Propylthiouracil may also be used for purposes not listed in this medication guide.

Propylthiouracil can cause serious or fatal liver problems. Stop taking propylthiouracil and call your doctor right away if you have upper stomach pain, nausea, vomiting, loss of appetite, fever, itching, tiredness, dark urine, clay-colored stools, or yellowing of your skin or eyes.

Propylthiouracil comes as a tablet to take by mouth. It is usually taken three times a day, once every 8 hours. Follow the directions on your prescription label carefully, and ask your doctor or pharmacist to explain any part you do not understand. Take propylthiouracil exactly as directed. Do not take more or less of it or take it more often than prescribed by your doctor.

Your doctor may decrease your dose of propylthiouracil once your condition is controlled.

Continue to take propylthiouracil even if you feel well. Do not stop taking propylthiouracil without talking to your doctor.

Follow all directions on your prescription label and read all medication guides or instruction sheets. Your doctor may occasionally change your dose. Use the medicine exactly as directed.

Propylthiouracil is usually taken 3 times per day.

You will need frequent blood tests to check your thyroid.

Call your doctor if you have unusual bruising or bleeding, or signs of infection (fever, chills, sore throat).

Tell your doctor if you have a planned surgery.

Store at room temperature away from moisture and heat.

You should not use propylthiouracil if you are allergic to it.

Tell your doctor if you have ever had liver problems.

In very rare cases, propylthiouracil has caused liver failure and death in pregnant women during the second or third trimester of pregnancy. Tell your doctor if you are pregnant or plan to become pregnant.

Tell your doctor if you are breastfeeding.

Propylthiouracil may cause liver failure in children, but is sometimes used in children who cannot be treated with other medications. Do not give this medicine to a child without your doctor's advice.

Take the medicine as soon as you can, but skip the missed dose if it is almost time for your next dose. Do not take two doses at one time.

Get your prescription refilled before you run out of medicine completely.

Seek emergency medical attention or call the Poison Help line at 1-800-222-1222.

Overdose symptoms may include fever, chills, itching, upset stomach, nausea, vomiting, swelling, headache, or joint pain.

Keep this medication in the container it came in, tightly closed, and out of reach of children. Store it at room temperature and away from excess heat and moisture (not in the bathroom).

Unneeded medications should be disposed of in special ways to ensure that pets, children, and other people cannot consume them. However, you should not flush this medication down the toilet. Instead, the best way to dispose of your medication is through a medicine take-back program. Talk to your pharmacist or contact your local garbage/recycling department to learn about take-back programs in your community. See the FDA's Safe Disposal of Medicines website (http://goo.gl/c4Rm4p) for more information if you do not have access to a take-back program.

It is important to keep all medication out of sight and reach of children as many containers (such as weekly pill minders and those for eye drops, creams, patches, and inhalers) are not child-resistant and young children can open them easily. To protect young children from poisoning, always lock safety caps and immediately place the medication in a safe location – one that is up and away and out of their sight and reach. http://www.upandaway.org

Unless your doctor tells you otherwise, continue your normal diet.

Avoid driving or hazardous activity until you know how propylthiouracil will affect you. Your reactions could be impaired.

Get emergency medical help if you have signs of an allergic reaction (hives, difficult breathing, swelling in your face or throat) or a severe skin reaction (fever, sore throat, burning eyes, skin pain, red or purple skin rash with blistering and peeling).

Propylthiouracil can cause liver damage (especially during the first 6 months of treatment). Liver failure can be fatal or may require a liver transplant. Stop taking propylthiouracil and call your doctor right away if you have signs of liver damage:

• nausea, vomiting, upper stomach pain;

• itching;

• fever, tiredness;

• loss of appetite;

• dark urine, clay-colored stools; or

• jaundice (yellowing of the skin or eyes).

Also call your doctor at once if you have:

• fever, chills, sore throat, mouth sores, feeling light-headed;

• unusual bleeding;

• purple or red discoloration of your skin;

• skin rash, skin pain or swelling;

• pink or dark urine, foamy urine, little or no urination;

• shortness of breath, or if you cough up blood; or

• new or worsening symptoms of lupus--joint pain, and a skin rash on your cheeks or arms that worsens in sunlight.

Common side effects of propylthiouracil may include:

• nausea, vomiting, stomach pain;

• itching or tingling, nerve pain;

• joint or muscle pain;

• swollen glands;

• headache, drowsiness, dizziness;

• swelling in your hands or feet;

• decreased sense of taste; or

• hair loss.

This is not a complete list of side effects and others may occur. Call your doctor for medical advice about side effects. You may report side effects to FDA at 1-800-FDA-1088.

Tell your doctor about all your other medicines, especially:

• digoxin (digitalis);

• theophylline;

• heart or blood pressure medication; or

• a blood thinner--warfarin, Coumadin, Jantoven.

This list is not complete. Other drugs may affect propylthiouracil, including prescription and over-the-counter medicines, vitamins, and herbal products. Not all possible drug interactions are listed here.

Keep all appointments with your doctor and the laboratory. Your doctor will order certain lab tests to check your body's response to propylthiouracil.

Do not let anyone else take your medication. Ask your pharmacist any questions you have about refilling your prescription.

It is important for you to keep a written list of all of the prescription and nonprescription (over-the-counter) medicines you are taking, as well as any products such as vitamins, minerals, or other dietary supplements. You should bring this list with you each time you visit a doctor or if you are admitted to a hospital. It is also important information to carry with you in case of emergencies.