Table 1 Obtaining continuous dopamine receptor stimulation: adjunctive therapies traditionally utilized to treat existing motor complications

DrugRoute of administrationMechanismSite of actionBenefit
Levodopa controlled-release formulationsPOProlonged absorptionPresynapticImprovement in wearing-off symptoms
Sinemet CR and Madopar HBS)Increased bioavailability
Entacapone, TolcaponePOCOMT inhibition Increased bioavailabilityPresynapticImprovement in wearing-off and on-off symptoms
Levodopa-sparing
SelegelinePOMAO-B inhibition Increased bioavailabilityPresynapticImprovement in wearing-off symptoms
Levodopa-sparing
Dopamine agonistsPODirect stimulation of dopamine receptorsPostsynapticImprovement in wearing-off and on symptoms
SC infusionImprovement in dyskinesias (high doses or infusion)
IV infusionLevodopa-sparing