▁causes . ▁ ▁It ▁is ▁on ▁the ▁World ▁Health ▁Organ ization ' s ▁List ▁of ▁Ess ential ▁Medic ines , ▁the ▁saf est ▁and ▁most ▁effective ▁medic ines ▁needed ▁in ▁a ▁health ▁system . ▁It ▁is ▁available ▁as ▁a ▁generic ▁medic ation ▁and ▁is ▁moder ately ▁expensive . ▁The ▁wh oles ale ▁price ▁in ▁the ▁developing ▁world ▁is ▁about ▁US $ 1 . 8 0 ▁to ▁$ 3 . 0 0 ▁a ▁month . ▁In ▁the ▁United ▁States , ▁a ▁month ' s ▁supply ▁costs ▁about ▁$ 5 0 ▁to ▁$ 1 5 0 . ▁In ▁ 2 0 1 7 , ▁it ▁was ▁the ▁ 1 8 4 th ▁most ▁commonly ▁pres cribed ▁medic ation ▁in ▁the ▁United ▁States , ▁with ▁more ▁than ▁three ▁million ▁pres cri ptions . ▁ ▁Medical ▁uses ▁ ▁Park inson ' s ▁disease ▁It ▁is ▁primarily ▁used ▁to ▁improve ▁the ▁sympt oms ▁of ▁Park inson ' s ▁disease ▁but ▁does ▁not ▁change ▁the ▁course ▁of ▁the ▁disease . ▁It ▁can ▁take ▁two ▁to ▁three ▁weeks ▁of ▁treatment ▁before ▁benefits ▁are ▁seen . ▁Each ▁do se ▁then ▁begins ▁working ▁in ▁about ▁ten ▁minutes ▁to ▁two ▁hours ▁depending ▁on ▁the ▁form ulation , ▁with ▁a ▁duration ▁of ▁effect ▁of ▁about ▁five ▁hours . ▁ ▁A ▁form ulation ▁that ▁can ▁be ▁given ▁in ▁an ▁int ra - int est inal ▁p ump , ▁known ▁as ▁Du od op a , ▁is ▁being ▁developed . ▁ ▁Other ▁Other ▁uses ▁include ▁for ▁dop am ine - respons ive ▁d yst onia ▁(