Parkinson's LOs

• Complications of levodopa/carbidopa therapy

  Most pts eventually develop motor complications after several years of use

  • Wearing off: loss of clinical effect towards end of dosing interval
  • Dyskinesias: involuntary movements involving face, neck, trunk and upper extremities
  • On-off phenomenon: rapid transformations from normal/controlled motor activity to bradykinetic or uncontrolled motor activity
  • Freezing: drug-resistant off period or inability to initiate motor function, aka starting hesitation
• Methods to help with complications from levodopa/carbidopa therapy

  Some clinicians to prefer delaying use until sx become very bothersome because of high likelihood of developing motor complications
• Key counseling for proper administration of levodopa/carbidopa

  • Most oral forms should be administered on an empty stomach (either 30 mins before or 1 hour after meal)
  • Amino acids (such as in high protein meals) or high fatty meals can compete w/ levodopa for absorption
  • May take with non-protein snack to decrease nausea
  • Available as ODT, immediate and extended release tablets, extended release capsules (can be taken without regard to meals), enteral suspension
• What medications can be used for treatment of Parkinson's and restless leg syndrome

  Dopamine agonists → Pramipexole and Ropinirole (Requip)
• Limitations to using dopamine or levodopa as drug therapy

  • Dopamine: cannot be administered for therapeutic effects to treat PD because it does not cross the BBB
  • Levodopa: can cross BBB but is extensively metabolized in the GI tract and peripheral tissues

  1. Carbidopa prevents conversion of levodopa to dopamine in the GI tract and peripheral tissues , also reduces levodopa dose requirements and improves tolerability (less nausea, orthostasis, and cardiac AE)