Classes
DEA Class; Rx
Common Brand Names; PTU
- Antithyroid Agents
Description
Oral thio-urea derivative antithyroid agent
Used for various hyperthyroid conditions including Graves disease
Due to hepatotoxicity risk reserved for patients intolerant of methimazole or in whom radioiodine therapy or surgery are not appropriate, except during the first trimester of pregnancy, when PTU is preferred over methimazole
Indications
Contraindications
Hypersensitivity
Adverse Effects
Agranulocytosis
Aplastic anemia
Dermatologic reactions
Hepatitis
Polyarthritis
Drowsiness
Fever
Headache
Vertigo
Alopecia
Erythema nodosum
Exfoliative dermatitis
Skin rash
Skin ulcers
Goiter
Weight gain
Constipation
Loss of taste
Granulopenia
Leukopenia
Thrombocytopenia
Warnings
Risk of severe rare immunoallergenic 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 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 drug readily crosses placental membranes, propylthiouracil can cause fetal goiter and cretinism when administered to a pregnant woman
Pregnancy and Lactation
Pregnancy Category: D
Lactation: distributed in breast milk, contraindicated by some sources (AAP Committee states compatible w/ nursing ; AAFP states safe for nursing)
Maximum Dosage
PTU has a narrow therapeutic window; individualize dosage. General max. doses for routine treatment of hyperthyroidism are listed. Higher doses in the treatment of thyrotoxicosis are typically necessary.
900 mg/day PO; 1.2 grams/day PO in severe disease.
900 mg/day PO; 1.2 grams/day PO in severe disease.
300 mg/day PO or maximum based on weight: 7 mg/kg/day PO. If growth is complete, doses used may be similar to adult dosing.
11 years and older: 300 mg/day PO. Usual weight based maximum: 7 mg/kg/day PO.
6 to 10 years: 150 mg/day PO. Usual weight based maximum: 7 mg/kg/day PO.
Less than 6 years: Safety and efficacy have not been established.
Safety and efficacy have not been established.
10 mg/kg/day PO has been used off-label for neonatal Graves’ disease.
How supplied
Propylthiouracil
tablet
- 50mg
