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propylthiouracil (PTU)

Propyl-Thyracil (CA)

Pharmacologic class: Thioamide derivative

Therapeutic class: Antithyroid agent

Pregnancy risk category D

FDA Box Warning

• Drug has caused severe liver injury and acute liver failure, in some cases fatal. These reports of hepatic reactions include cases requiring liver transplant.

• Reserve drug for patients intolerant of methimazole and in whom radioactive iodine therapy or surgery isn't appropriate for management of hyper-thyroidism.

• Because of risk of fetal abnormalities associated with methimazole, propylthiouracil may be treatment of choice when an antithyroid drug is indicated during or just before first trimester.


Directly interferes with thyroid synthesis by preventing iodine from combining with thyroglobulin, leading to decreased thyroid hormone levels


Tablets: 50 mg

Indications and dosages


Adults: Initially, 300 to 450 mg P.O. daily in equally divided doses q 8 hours; for maintenance, 100 to 150 mg P.O. daily.

Thyrotoxic crisis

Adults: 200 mg P.O. q 4 to 6 hours during first 24 hours, then a maintenance dosage of 100 to 150 mg P.O. daily


• Hypersensitivity to drug


Use cautiously in:

• decreased bone marrow reserve

• pregnancy and breastfeeding patients

• children.


• Give with meals to reduce GI upset.

• Be aware that drug shouldn't be used in children unless patient is allergic to or intolerant of methimazole, and there are no other treatment options available.

Adverse reactions

CNS: drowsiness, headache, vertigo, neuritis, paresthesia

GI: nausea, vomiting, diarrhea, epigastric distress

Hematologic: agranulocytosis, leukopenia, thrombocytopenia

Hepatic: jaundice, hepatic necrosis, liver failure

Metabolic: hypothyroidism

Musculoskeletal: joint pain, myalgia

Skin: rash, urticaria, pruritus, skin discoloration, alopecia, cutaneous vasculitis

Other: taste loss, fever, lymphadenopathy, parotitis, edema


Drug-drug. Anticoagulants: potentiation of anticoagulant effect

Drug-diagnostic tests. Alanine aminotransferase, alkaline phosphatase, aspartate aminotransferase, bilirubin, lactate dehydrogenase: increased levels

Granulocytes, platelets: decreased levels Prothrombin time: prolonged

Patient monitoring

• Monitor CBC and liver and thyroid function tests.

• Assess for signs and symptoms of hypothyroidism (cold intolerance, nonpitting edema, fatigue, weight gain, and depression).

Monitor for severe rash, fever, jaundice, or enlarged cervical lymph nodes. If present, stop therapy and notify prescriber.

Patient teaching

• Instruct patient to take with meals to reduce GI upset.

• Teach patient to recognize and report signs and symptoms of hypothyroidism and jaundice.

• Advise patient to discuss iodine intake (as in iodized salt and shellfish) with prescriber.

• Tell patient to avoid over-the-counter cold remedies that contain iodine.

• Caution patient to avoid driving and other hazardous activities until he knows how drug affects concentration and alertness.

• Advise female patient of childbearing age to discuss pregnancy or breastfeeding with prescriber before taking.

• As appropriate, review all other significant and life-threatening adverse reactions and interactions, especially those related to the drugs and tests mentioned above.


Abbreviation for propylthiouracil.




References in periodicals archive ?
Common adverse effects found in use of antithyroid medications were dermatologic complications with methimazole and hepatotoxic effects with PTU.
Cell-culture studies have shown that PTU leads to an increase in the secretion of transforming growth factor-b1 (TGFb1) and a decrease in concentrations of IL-6 and tumour necrosis factor-[alpha] (TNF[alpha]) (LI et al.
Moreover, lesser PTU recorded in early planting was also related with least GDDs accumulation to start emergence but after that early planted crop experienced higher PTU to switch into next phenophases chiefly due to higher GDDs accretion on respective stages than delay planted crop (Table 3); as PTU is a product of GDDs and possible sunshine hours.
Replying to another question, he said that he is ready to set up the campuses of PTU in other provinces as well so that the project could benefit the whole country.
PTU, a phenoloxidase inhibitor, exhibited a concentration-dependent inhibition of [C.
The two doctors published a letter in the April 9 New England Journal of Medicine urging doctors not to give PTU as an initial treatment to children for an overactive thyroid.
When PTU was administered to euthyroid or hyperthyroid animals, thyroid hormone concentrations, hepatic 5'DI and G-6-Pase activities also decreased as compared to the values of control or hyperthyroid groups.
The amount of PTU ingested daily was estimated for each animal; the daily amount of water consumed was inferred from the amount of water provided, minus the value found divided by the number of animals in the cage.
These include Tapazole (methimazole) and PTU (propylthiouracil).
PB induced hepatic uridine diphosphate-glucuronyltransferase (UDPGT) activity almost 2-fold, whereas PTU reduced hepatic 5'-deiodinase I (5'-DI) activity to < 10% of control in support of previous reports regarding the mechanism of action of each chemical.
Los PTU son considerados por las Naciones Unidas como territorios no autonomos que deben obtener su independencia en los proximos anos, aunque algunos paises optan por la libre asociacion con un Estado independiente (este es el caso de Aruba).