Thyroid Hormone Therapy

Thyroid hormone therapy is usually a replacement decision and a delayed-feedback dosing exercise. In primary hypothyroidism, levothyroxine supplies T4; the pituitary TSH response changes slowly, so symptoms or a laboratory result obtained too soon should not trigger a rapid dose change. The NP must establish that replacement is indicated, determine whether TSH is a valid treatment target, start cautiously when myocardial reserve is limited, and protect absorption through administration and interaction review. Pregnancy, central hypothyroidism, congenital disease, thyroid-cancer follow-up, and myxedema coma each change the usual pathway.