Levothyroxine
Hypothyroidism, TSH suppression after thyroid cancer
Indications
- Hypothyroidism
- TSH suppression after thyroid cancer
Adult dosing
- standard: dose: 1.6; unit: mcg/kg/day; route: PO; interval: Take on empty stomach, 30-60 min before breakfast; weightBased: true; elderly: dose: 25; unit: mcg; route: PO daily; interval: Start low, increase by 12.5-25mcg q4-6 weeks; fixed: true
Contraindications
- Untreated adrenal insufficiency (treat with cortisol first)
- Acute MI (relative — start low dose)
Clinical pearls
- Full replacement dose is ~1.6 mcg/kg/day for most adults
- Elderly or cardiac patients: start 25mcg and increase slowly
- Take consistently: same time daily, empty stomach, separate from calcium/iron by 4 hours
- Recheck TSH 4-6 weeks after any dose change
- Pregnancy: increase dose by ~30% as soon as pregnancy confirmed
Source and review
- ATA Guidelines for Hypothyroidism 2014. Last reviewed: 2024-11-01