Achievable logoAchievable logo
PTCE
Sign in
Sign up
Purchase
Textbook
Practice exams
Support
How it works
Exam catalog
Mountain with a flag at the peak
Textbook
Introduction
1. Medications
2. Patient safety and quality assurance
3. Order entry and processing
4. Federal requirements
Wrapping up
Achievable logoAchievable logo
1.4.8.3 Parkinson's disease
Achievable PTCE
1. Medications
1.4. Medications by organ system
1.4.8. Drugs of the nervous system
Our PTCE course is now in "early access" - get 50% off for a limited time.

Parkinson's disease

2 min read
Font
Discuss
Share
Feedback

Parkinson’s disease is a common degenerative disorder of the brain. It’s characterized by:

  • Tremor
  • Rigidity (muscle stiffness)
  • Difficulty with balance

Parkinson’s disease is caused by the loss of dopamine-secreting neurons in a part of the brain called the substantia nigra.

Many drugs are used to manage Parkinson’s disease, and carbidopa-levodopa is the cornerstone of therapy.

  • Levodopa is converted to dopamine in the brain.
  • Carbidopa reduces the breakdown of levodopa before it reaches the brain, so more levodopa can be delivered from the bloodstream into the brain.
Substantia Nigra
Substantia Nigra

Table showing drugs used to treat Parkinson’s disease and their mechanism of action

Mechanism of action Generic name and common brands
Increase dopamine levels in the brain Carbidopa-levodopa (Sinemet, Parcopa, Rytary, Dhivy)
Dopamine agonists that mimic the action of dopamine Apomorphine (Apokyn, Kynmobi), pramipexole (Mirapex), ropinirole (Requip), rotigotine (Neupro)
MAO-B inhibitors that block the breakdown of dopamine Rasagiline (Azilect), selegiline (Carbex, Eldepryl)
COMT inhibitors that block the breakdown of dopamine Entacapone (Comtan), tolcapone (Tasmar), opicapone (Ongentys)
Anticholinergics that block the action of neurotransmitter acetylcholine Benztropine (Cogentin), trihexyphenidyl (Artane)
Adenosine receptor antagonist Istradefylline (Nourianz)
Increase dopamine levels in the brain Fos Levodopa-fos carbidopa (Vyalev, Produodopa)
Unknown mechanisms Amantadine (Osmolex, Gocovri, Symmetrel)

Common adverse effects include:

  • Nausea and vomiting
  • Dizziness and headache
  • Sleepiness
  • Postural hypotension
  • Confusion
  • Hallucinations and delusions
  • Agitation
  • Dry mouth

Anticholinergics are more likely to cause:

  • Urinary retention
  • Dry mouth
  • Cognitive dysfunction

Sign up for free to take 5 quiz questions on this topic

All rights reserved ©2016 - 2026 Achievable, Inc.