Yes

Antithyroid Agent

Palliative treatment of hyperthyroidism as an adjunct to ameliorate hyperthyroidism in preparation for surgical treatment or radioactive iodine therapy and in the management of thyrotoxic crisis. The use of antithyroid thioamides is as effective in elderly as they are in younger adults; however, the expense, potential adverse effects, and inconvenience (compliance, monitoring) make them undesirable. The use of radioiodine, due to ease of administration and less concern for long-term side effects and reproduction problems, makes it a more appropriate therapy.

D

Hypersensitivity to propylthiouracil or any component

Use with caution in patients >40 years of age because PTU may cause hypoprothrombinemia and bleeding, use with extreme caution in patients receiving other drugs known to cause agranulocytosis; may cause agranulocytosis, thyroid hyperplasia, thyroid carcinoma (usage >1 year); breast-feeding (enters breast milk)

>10%:

Central nervous system: Fever

Dermatologic: Skin rash

Hematologic: Leukopenia

1% to 10%:

Central nervous system: Dizziness

Gastrointestinal: Nausea, vomiting, loss of taste perception, stomach pain

Hematologic: Agranulocytosis

Miscellaneous: SLE-like syndrome

<1%: Edema, cutaneous vasculitis, drowsiness, vertigo, headache, drug fever, urticaria, pruritus, exfoliative dermatitis, alopecia, goiter, constipation, weight gain, swollen salivary glands, thrombocytopenia, bleeding, aplastic anemia, cholestatic jaundice, hepatitis, arthralgia, paresthesia, neuritis, nephritis

Symptoms of overdose include nausea, vomiting, epigastric pain, headache, fever, arthralgia, pruritus, edema, pancytopenia, epigastric distress, headache, fever, CNS stimulation or depression

Treatment is supportive; monitor bone marrow response, forced diuresis, peritoneal and hemodialysis, as well as charcoal hemoperfusion

Increased effect: Increases anticoagulant activity

Inhibits the synthesis of thyroid hormones by blocking the oxidation of iodine in the thyroid gland; blocks synthesis of thyroxine and triiodothyronine

Onset of action: For significant therapeutic effects 24-36 hours are required

Peak effect: Remissions of hyperthyroidism do not usually occur before 4 months of continued therapy

Distribution: Concentrated in the thyroid gland

Protein binding: 75% to 80%

Metabolism: Hepatic

Bioavailability: 80% to 95%

Half-life: 1.5-5 hours; End-stage renal disease: 8.5 hours

Time to peak serum concentration: Oral: Within 1 hour; persists for 2-3 hours

Elimination: 35% excreted in urine

Oral: Administer in 3 equally divided doses at approximately 8-hour intervals. Adjust dosage to maintain T₃, T₄, and TSH levels in normal range; elevated T₃ may be sole indicator of inadequate treatment. Elevated TSH indicates excessive antithyroid treatment.

or

6-10 years: 50-150 mg/day

>10 years: 150-300 mg/day

Maintenance: Determined by patient response or1/3 to 2/3 of the initial dose in divided doses every 8-12 hours. This usually begins after 2 months on an effective initial dose.

Adults: Initial: 300 mg/day in divided doses every 8 hours. In patients with severe hyperthyroidism, very large goiters, or both, the initial dosage is usually 450 mg/day; an occasional patient will require 600-900 mg/day; maintenance: 100-150 mg/day in divided doses every 8-12 hours

Elderly: Use lower dose recommendations; Initial: 150-300 mg/day

Withdrawal of therapy: Therapy should be withdrawn gradually with evaluation of the patient every 4-6 weeks for the first 3 months then every 3 months for the first year after discontinuation of therapy to detect any reoccurrence of a hyperthyroid state.

Dosing adjustment in renal impairment: Adjustment is not necessary

Administer at the same time in relation to meals each day, either always with meals or always between meals

CBC with differential, prothrombin time, liver function tests, thyroid function tests (TSH, T₃, T₄); periodic blood counts are recommended chronic therapy

Normal laboratory values:

Serum T₃: 90-185 ng/dL

Free thyroxine index (FT₄ I): 6-10.5

TSH: 0.5-4.0 microU/mL

May cause dizziness or drowsiness

Leukopenia is common; avoid clozapine and carbamazepine

No information available to require special precautions

No effects or complications reported

Take as directed, at the same time each day around-the-clock; do not miss doses or make up missed doses. This drug will need to be taken for an extended period of time to achieve appropriate results. You may experience nausea or vomiting (small frequent meals may help), dizziness or drowsiness (use caution when driving or engaging in tasks that require alertness until response to drug is known). Report rash, fever, unusual bleeding or bruising, unresolved headache, yellowing of eyes or skin, or changes in color of urine or feces, unresolved malaise. Pregnancy precautions: Do not get pregnant; use appropriate contraceptive measures to prevent possible harm to the fetus.

Monitor CBC with differential, prothrombin time, liver function tests, thyroid function tests (T₄, T₃, TSH); periodic blood counts are recommended chronic therapy

Tablet: 50 mg

A 5 mg/mL oral suspension was stable for 10 days when refrigerated when compounded as follows:

Shake well before using and keep in refrigerator; protect from light

Nahata MC and Hipple TF, Pediatric Drug Formulations, 3rd ed, Cincinnati, OH: Harvey Whitney Books Co, 1997.

Jackson GL, Flickinger FW, and Wells LW, "Massive Overdosage of Propylthiouracil," Ann Intern Med, 1979, 91(3):418-9.

Limaye A and Ruffolo R, "Propylthiouracil-Induced Fatal Hepatic Necrosis," Am J Gastroenterol, 1987, 82(2):152-4.

Raby C, Lagorce JF, Jambut-Absil AC, et al, "The Mechanism of Action of Synthetic Antithyroid Drugs: Iodine Complexation During Oxidation of Iodide," Endocrinology, 1990, 126(3):1683-91.

Romas E, Henderson DR, and Kirkham BW, "Propylthiouracil Therapy: An Unusual Cause of Antineutrophil Cytoplasmic Antibody Associated Alveolar Hemorrhage," J Rheumatol, 1995, 22(4):803.