DR D ) ▁and ▁rest less ▁legs ▁synd rome . ▁ ▁There ▁is ▁tent ative ▁evidence ▁that ▁it ▁is ▁useful ▁in ▁amb ly op ia ▁when ▁used ▁with ▁other ▁treat ments . ▁ ▁Side ▁effects ▁Common ▁side ▁effects ▁include ▁movement ▁problems , ▁and ▁n ause a . ▁Most ▁common ▁early ▁side ▁effect ▁is ▁hall uc in ations , ▁as ▁movement ▁problems ▁manifest ▁ 5 – 1 0 ▁years ▁after ▁init iation ▁of ▁treatment . ▁More ▁serious ▁side ▁effects ▁include ▁de pression , ▁low ▁blood ▁pressure ▁with ▁standing , ▁sudden ▁on set ▁of ▁sleep iness , ▁and ▁the ▁comp ulsion ▁to ▁gam ble , ▁eng age ▁in ▁sexual ▁behavior , ▁or ▁other ▁risk - t aking ▁behavior . ▁ ▁Mechan ism ▁of ▁action ▁ ▁Le vod op a ▁is ▁converted ▁to ▁dop am ine ▁via ▁the ▁action ▁of ▁a ▁naturally ▁occurr ing ▁en zym e ▁called ▁D OP A ▁dec ar box yl ase . ▁This ▁occurs ▁both ▁in ▁the ▁peri pher al ▁circul ation ▁and ▁in ▁the ▁central ▁nerv ous ▁system ▁after ▁le vod op a ▁has ▁crossed ▁the ▁blood ▁brain ▁bar rier . ▁Activ ation ▁of ▁central ▁dop am ine ▁re cept ors ▁impro ves ▁the ▁sympt oms ▁of ▁Park inson ' s ▁disease ; ▁however , ▁activation ▁of ▁peri pher al ▁dop am ine ▁re cept ors ▁causes ▁n ause a ▁and ▁vom iting . ▁For ▁this ▁reason ▁le vod op a ▁is ▁usually ▁admin ister ed ▁in ▁combination ▁with ▁a ▁D OP A ▁dec ar box yl ase ▁in hib