The Collaborative International Dictionary of English v.0.48:

levodopa \le`vo*do"pa\ (l[=e]`v[-o]*d[=o]"p[.a]), a. [Levo- +
   DOPA, dihydroxyphenylalanine.] (Chem. & Biochem.)
   A substance used as a therapy for Parkinson's Disease; the
   L form of Dopa; L-dihydroxyphenylalanine; L-hydroxytyrosine
   (C9H11NO4); also called L-dopa. In the body it is
   converted by the enzyme dopa-decarboxylase into dopamine, the
   form in which it is active in the brain, affecting neural
   impulse transmission.
   [PJC]

WordNet (r) 3.0 (2006):

levodopa
    n 1: the levorotatory form of dopa (trade names Bendopa and
         Brocadopa and Larodopa); as a drug it is used to treat
         Parkinson's disease [syn: L-dopa, levodopa, Bendopa,
         Brocadopa, Larodopa]