levothyroxine

noun

le·​vo·​thy·​rox·​ine

variants or British laevothyroxine

ˌlē-vō-thī-ˈräk-ˌsēn, -sən 

: the levorotatory isomer of thyroxine that is administered in the form of its sodium salt C₁₅H₁₀I₄NNaO₄ in the treatment of hypothyroidism see levothroid, levoxyl, synthroid