Propylthiouracil

Propylthiouracil is a prescription medication used to treat Hyperthyroidism, and Graves Disease.

• Propylthiouracil is available under the following different brand names: PTU

Adult and pediatric dosage

Tablet

• 50mg

Hyperthyroidism

Adult dosage

• 300-450 mg/day orally divided every 8 hours initially (may require up to 600-900 mg/day)
• Maintenance: 100-150 mg/day divided every 8 hours

Pediatric dosage

• Neonates (younger than 28 days old): 5-10 mg/kg/day orally divided every 8 hours initially
• Children younger than 6 years of age: 5-7 mg/kg/day orally divided every 8 hours initially or
• Children 6-10 years of age: 50-150 mg/day orally divided every 8 hours
• Children 10 years of age: 150-300 mg/day
• Maintenance: Usually 1/3-2/3 of initial dose based on response divided every 8-12 hours

Graves Disease

Adult dosage

• 50-150 mg orally every 8 hours initially
• Maintenance: 50 mg orally every 8-12 hours for up to 12-18 months; then taper and discontinue if euthyroidism restored (TSH) is normal.

Dosage Considerations – Should be Given as Follows: 

• See “Dosages”.

Common side effects of Propylthiouracil include:

• nausea, 
• vomiting, 
• stomach pain, 
• itching or tingling, 
• nerve pain, 
• joint or muscle pain, 
• swollen glands, 
• headache, 
• drowsiness, 
• dizziness, 
• swelling in hands or feet, 
• decreased sense of taste, and 
• hair loss

Serious side effects of Propylthiouracil include:

• hives, 
• difficult breathing, 
• swelling in the face or throat, 
• fever, 
• sore throat, 
• burning in the eyes, 
• skin pain, 
• red or purple skin rash that spreads and causes blistering and peeling, 
• nausea, 
• vomiting, 
• upper stomach pain, 
• itching, 
• fever, 
• tiredness, 
• loss of appetite, 
• dark urine, 
• clay-colored stools, 
• yellowing of the skin or eyes (jaundice), 
• fever, 
• chills, 
• mouth sores, 
• lightheadedness, 
• unusual bleeding, 
• purple or red discoloration of the skin, 
• skin rash, 
• skin pain or swelling, 
• pink or dark urine, 
• foamy urine, 
• little or no urination, 
• shortness of breath, 
• coughing up blood, 
• joint pain, and
• skin rash or cheeks or arms that worsens in sunlight

Rare side effects of Propylthiouracil include:

• none 

If your medical doctor is using this medicine to treat your pain, your doctor or pharmacist may already be aware of any possible drug interactions and may be monitoring you for them.  Do not start, stop, or change the dosage of any medicine before checking with your doctor, health care provider, or pharmacist first

• Propylthiouracil has severe interactions with the following drug:
  • sodium iodide I-131
• Propylthiouracil has serious interactions with the following drugs:
  • carbamazepine
  • clozapine
  • macimorelin
  • methimazole
  • pexidartinib
  • pretomanid
• Propylthiouracil has moderate interactions with at least 15 other drugs:
• Propylthiouracil has minor interactions with the following drugs:
  • cadexomer iodine
  • iodinated glycerol
  • iodine

This information does not contain all possible interactions or adverse effects. Visit the RxList Drug Interaction Checker for any drug interactions. Therefore, before using this product, tell your doctor or pharmacist of all the products you use. Keep a list of all your medications with you, and share this information with your doctor and pharmacist. Check with your health care professional or doctor for additional medical advice, or if you have health questions, concerns.

Contraindications

• Hypersensitivity 

Effects of drug abuse

• None

Short-Term Effects

• See “What Are Side Effects Associated with Using Propylthiouracil?”

Long-Term Effects

• See “What Are Side Effects Associated with Using Propylthiouracil?”

Cautions

• Risk of severe rare immune allergic hepatitis
• Severe dermatologic reactions reported
• Discontinue in presence of unexplained fever
• Lupus-like syndrome reported (may need to discontinue)
• Glomerulonephritis and interstitial nephritis with acute renal failure reported
• Interstitial pneumonitis may occur
• High relapse rate (more likely in smokers)
• Agranulocytosis within first 3 months of therapy reported; instruct patients to immediately report any symptoms suggestive of agranulocytoses, such as fever or sore throat; leukopenia, thrombocytopenia, and aplastic anemia (pancytopenia) may also occur; discontinue treatment if agranulocytosis, aplastic anemia (pancytopenia) suspected, and patient's bone marrow indices obtained
• Patients who receive therapy should be under close surveillance and counseled regarding the necessity of immediately reporting any evidence of illness, particularly sore throat, skin eruptions, fever, headache, or general malaise; in such cases, white blood cell and differential counts should be obtained to determine whether agranulocytosis has developed; particular care should be exercised with patients who are receiving concomitant drugs known to be associated with agranulocytosis
• Cases of vasculitis resulting in severe complications and death reported; cases of vasculitis include glomerulonephritis, leukocytoclastic cutaneous vasculitis, alveolar/pulmonary hemorrhage, cerebral angiitis, and ischemic colitis; severe cases require treatment with corticosteroids, immunosuppressant therapy, and plasmapheresis; if vasculitis is suspected, discontinue therapy and initiate appropriate intervention
• Propylthiouracil can cause hypothyroidism necessitating routine monitoring of TSH and free T4 levels with adjustments in dosing to maintain a euthyroid state; because the drug readily crosses placental membranes, propylthiouracil can cause fetal goiter and cretinism when administered to a pregnant woman

Liver toxicity

• Patients should be instructed to report any symptoms of hepatic dysfunction (anorexia, pruritus, jaundice, light-colored stools, dark urine, right upper quadrant pain, etc.), particularly in the first six months of therapy; when these symptoms occur, measurement should be made of liver function (bilirubin, alkaline phosphatase) and hepatocellular integrity (ALT/AST levels)
• Biochemical monitoring of liver function (bilirubin, alkaline phosphatase) and hepatocellular integrity (ALT, AST) is not expected to attenuate the risk of severe liver injury due to the rapid and unpredictable onset
• Liver injury resulting in liver failure, liver transplantation, or death, reported with therapy in adult and pediatric patients
• No cases of liver failure were reported with the use of methimazole in pediatric patients; therapy is not recommended for pediatric patients except when methimazole is not well-tolerated and surgery or radioactive iodine therapy are not appropriate therapies
• Patients should be informed of the risk of liver failure; patients should be instructed to report symptoms of hepatic dysfunction (anorexia, pruritus, right upper quadrant pain, etc.), particularly in the first six months of therapy
• When symptoms occur, therapy should be discontinued immediately and liver function tests and ALT and AST levels obtained; discontinue immediately if abnormal LFTs (transaminase is greater than 3 times ULN)

Pregnancy and Lactation

• Use in LIFE-THREATENING emergencies when no safer drug is available. Positive evidence of human fetal risk. 
• Distributed in breast milk, contraindicated by some sources (AAP Committee states compatible with nursing; AAFP states safe for nursing).