Propylthiouracil

Nursing pharmacology study reference (NCLEX-style monograph). Numeric values are standard teaching ranges for study and must be verified against current manufacturer labeling before clinical use. This is educational content, not prescribing guidance.

Propylthiouracil (brand name PTU) — Antithyroid; Thioamide.

Identification

• Therapeutic class: Antithyroid.
• Pharmacologic class: Thioamide.

Pharmacology

• Mechanism of action: Blocks thyroid hormone synthesis and peripheral T4-to-T3 conversion.
• Onset / peak / duration: Effect over weeks.
• Half-life / therapeutic level: Half-life 1 to 2 hours; monitor thyroid labs.

Clinical use

• Indications: Hyperthyroidism, especially first-trimester pregnancy and thyroid storm.
• Usual dose, route, frequency: 100 to 150 mg PO every 8 hours.
• Maximum dose / adjustments: Titrate to labs; reserved due to liver risk.

Safety

• Contraindications: Severe hepatic disease.
• Black box warning: Risk of severe, sometimes fatal, hepatotoxicity; reserve for situations where methimazole is unsuitable (such as the first trimester).
• Interactions: Same as methimazole.
• Pregnancy / lactation: Preferred antithyroid in the first trimester.
• High-alert: No.

Adverse effects

• Common side effects: Rash, GI upset, arthralgia.
• Serious effects to report: Hepatotoxicity, agranulocytosis (fever, sore throat).
• Antidote / reversal: None; discontinue.

Nursing process

• Assessment before administration: Thyroid labs, LFTs, CBC.
• Interventions during therapy: Multiple daily doses; monitor liver function.
• Monitor: Thyroid labs, LFTs, CBC.
• Evaluation / expected outcome: Controlled hyperthyroidism.

Patient teaching

• Patient teaching: Report fever, sore throat, or jaundice.
• Notify provider if: Yellow skin or eyes, dark urine, fever, sore throat.
• Administration tips: Every 8 hours, consistent timing.