Parkinson's Meds

• What meds are available for Parkinson's Disease

  • Dopamine precursors: Levodopa, Carbidopa, and combo (aka Sinemet)
  • Catechol o methyltransferase: Entacapone
  • Monamine oxidase inhibitors: Rasagiline, Selegiline
  • Antiviral: Amantadine
  • Dopamine agonists: Pramipexole, Ropinirole (Requip), Rotigotine
  • Cholinergic receptor antagonist: Benztropine
• Dopamine precursors

  Levodopa, Carbidopa aka Sinemet if combo

  • Levodopa is immediate precursor to dopamine and is able to cross the BBB 
  • anorexia, nausea, vomiting, tachycardia, ventricular extrasystoles, hypotension, discoloration of saliva and urine, visual/auditory hallucinations, dyskinesias, depression, psychosis, anxiety
  • contraindicated in closed angle glaucoma, hypersensitivity, concomitant MAOI use, caution in hx of melanoma
• Dopamine precursor clinical info

  • Interactions with MAOI (hypertensive crisis), Antipsychotic drugs (can block dopamine receptors, clozapine better), vitamin B6 (increase peripheral break down, but not an issue if using combo form) 
  • Absorption is affected by drugs that delay or promote gastric emptying
  • Most clinically effective therapy for PD symptoms, effective for all 3 cardinal symptoms (resting tremor, bradykinesia, rigidity)
• Catechol-o-methyltransferase: Entacapone


  • inhibit conversion of levodopa to 3-O-methyldopa in periphery and CNS, allowing for higher concentration
  • diarrhea, nausea, anorexia, dyskinesias, hallucinations, sleep disorders, fetal hepatic toxicity (tolcapone)
  • Contraindicated in hypersensitivity
  • May help reduce sx of “wearing off”, may need to decrease levodopa dose to avoid adverse dopaminergic effects
  • NOT useful as monotherapy, only in combo with levodopa
• Monamine oxidase inhibitors: Rasagiline, Selegiline


  • block oxidative degradation of dopamine through MAO-B inhibition 
  • confusion, dyskinesias, hallucinations, hypotension, insomnia, nausea, HTN crisis
  • Contraindicated with MAOIs, transdermal contraindication w/ SSRIs, SNRIs, tricyclic antidepressants, MAOIs, Meperidine
  • Can be initial therapy or adjunct with levodopa, selegiline has higher incidence of HTN and is metabolized by amphetamine so can lead to insomnia, Rasagiline 5x as potent
  • Theorized to slow disease progression caused by reduced oxidative stress
• Antiviral: Amantadine


  • An antiviral that increases release of dopamine, blocks cholinergic receptors, inhibits NMDA type of glutamate receptors
  • dry mouth, hypotension, livedo reticularis, nausea, restlessness, sedation, vivid dreams
  • renal dosage adjustment
  • Can be initial monotherapy for mild-moderate disease or adjunct w/ levodopa in advances disease, may improve rigidity and bradykinesia, and may be useful to tx dyskinesias associated with long term dopaminergic treatment
• Dopamine agonists: Pramipexole, Ropinirole (Requip), Rotigotine


  • directly stimulate dopamine receptors
  • nausea, hallucinations, insomnia, dizziness, constipation, hypotension, 
  • fewer long term motor complications but less effective, may need to decrease levodopa if taking together, does NOT cause fibrosis or peripheral vasospasm as seen with ergot derivative
  • Rotigotin is transdermal patch to tx early PD, admin once daily
  • Initial or adjunct w/ levodopa, longer duration of action than levodopa (good for pts w/ fluctuations in response to levodopa treatment)
• Cholinergic receptor antagonists: Benztropine

  • compete with acetylcholine at muscarinic receptors in the CNS
  • mood changes, dry mouth, vision problems, confusion, hallucinations, urinary retention, constipation
  • Contraindicated with glaucoma, prostatic hyperplasia, pyloric stenosis, dementia
  • Less effective than dopaminergic drugs but may be good as adjunct therapy, targets tremor more than other sx