Propylthiouracil Warnings and Precautions
Liver problems are a serious concern with propylthiouracil -- even life-threatening -- and people with cirrhosis, hepatitis, or other liver conditions may not be able to take it. Precautions and warnings with propylthiouracil also extend to women who are pregnant or breastfeeding. To ensure a safe treatment process, tell your healthcare provider about all drugs you are taking (including supplements) and all medical conditions you have.
- Liver disease, such as hepatitis, cirrhosis, or liver failure
- A bleeding disorder
- Any allergies, including to food, dyes, or preservatives.
Also, let your healthcare provider know if you are:
- Pregnant or thinking of becoming pregnant
Make sure to tell your healthcare provider about all of the medicines you take, including prescription and nonprescription medications, vitamins, and herbal supplements.
Some warnings and precautions to be aware of prior to taking propylthiouracil include the following:
- This medicine can cause serious liver reactions, which may result in death. Let your healthcare provider know right away if you develop signs of liver problems, such as:
- Yellow eyes or skin (jaundice)
- Upper-right abdominal pain (stomach pain)
- Loss of appetite
- Elevated liver enzymes (found using a blood test).
- Because propylthiouracil is more likely to cause liver failure compared to methimazole, another antithyroid medication, it should be used only for people allergic to or unable to tolerate methimazole, if no other treatments are available, or for women in the first trimester of pregnancy.
- Propylthiouracil can cause low blood cells, such as low white blood cells and low blood platelets. These conditions can be quite serious. Your healthcare provider should monitor your blood counts during treatment (using a simple blood test) to check for such problems. Let your healthcare provider know if you develop any signs of such problems, such as infections, sore throat, fever, or easy bruising or bleeding.
- You should avoid alcohol while taking this medication, as additive effects (such as increased drowsiness, confusion, or memory loss) could occur.
- Propylthiouracil could react with other medications (see Propylthiouracil Drug Interactions).
- This is a pregnancy Category D medication, which means it presents a definite risk to a woman's pregnancy. Check with your healthcare provider before taking this drug when pregnant (see Propylthiouracil and Pregnancy).