Propylthiouracil: Difference between revisions
| Line 26: | Line 26: | ||
==Adverse Reactions== | ==Adverse Reactions== | ||
===Serious=== | ===Serious=== | ||
''Both PTU and methimazole can cause agranulocytosis and hepatotoxicity, but to a lesser extent with methimazole'' | |||
*Agranulocytosis, aplastic anemia | *Agranulocytosis, aplastic anemia | ||
*Hepatotoxicity, liver failure | *Hepatotoxicity, liver failure | ||
*Nephritis | *Nephritis | ||
*Vasculitis | *Vasculitis | ||
===Common=== | ===Common=== | ||
Latest revision as of 06:03, 10 December 2019
Administration
- Type: Antithyroid
- Dosage Forms:
- Routes of Administration:
- Other common names: PTU
Adult Dosing
- Thyroid storm: 500-1000mg PO loading dose, followed by 250mg PO q4h
- Hyperthyroidism
- Initial: 50-300mg PO TID (based on severity)
- Maintenance: 50mg PO TID
- 1st trimester pregnancy: Use lowest dose needed to keep maternal total T3/T4 slightly above normal range for pregnancy, TSH suppressed, and free T4 at or slightly above upper limit of normal for nonpregnant women. Switch to methimazole for 2nd-3rd trimester
Pediatric Dosing
- >6yo: 50 mg PO daily, carefully uptitrated
Special Populations
- Pregnancy Rating: D - see dosing note above
- Lactation risk: Infant risk cannot be ruled out
- Renal dosing: No adjustment
- Hepatic dosing:
Contraindications
- Allergy to class/drug
Adverse Reactions
Serious
Both PTU and methimazole can cause agranulocytosis and hepatotoxicity, but to a lesser extent with methimazole
- Agranulocytosis, aplastic anemia
- Hepatotoxicity, liver failure
- Nephritis
- Vasculitis
Common
- Rash
Pharmacology
- Half-life: 0.9-4.3h
- Metabolism: Hepatic
- Excretion: Renal
Mechanism of Action
- Inhibits thyroperoxidase, blocking thyroid hormone synthesis in the thyroid. In target tissues, blocks 5'-deiodinase, thereby inhibiting conversion of T4 to active T3