Thionamides
- Inhibit thyroid-hormone synthesis
- Methimazole preferred for most hyperthyroid pts
- PTU favored in thyroid storm/early pregnancy
- Agranulocytosis is rare but dangerous
- Fever/sore throat → stop + check CBC urgently
- PTU has greater severe liver-toxicity risk
- They do not destroy preformed hormone
Class at a glance
- Inhibit thyroid-hormone synthesis
Practical pearls
- Methimazole preferred for most hyperthyroid pts
Members / distinctions
- Fever/sore throat → stop + check CBC urgently
- They do not destroy preformed hormone
Safety / monitoring
- PTU favored in thyroid storm/early pregnancy
- Agranulocytosis is rare but dangerous
- PTU has greater severe liver-toxicity risk
Self-check
- How does Thionamides work?
Inhibit thyroid-hormone synthesis. - What distinguishes PTU?
Greater severe liver-toxicity risk.
Drugs in this class (2)
Thionamides prescription history
Animated chart of estimated U.S. prescriptions per year, Thyroid meds (1893–2026). Antithyroid highlighted from 1947.
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