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- [Home](/)
- [Living with Parkinson's](/living-with-parkinsons)
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- [Prescription Medications](/living-with-parkinsons/treatment/prescription-medications)
 
 #  Adenosine A2A Antagonists 

 

   

  ## 💡 Quick Summary 

 - Adenosine A2A antagonists reduce Parkinson’s [“off” time](/events/2022/ww1130 "The Importance of Addressing On-Off Times in Parkinson’s") by blocking A2A receptors in the basal ganglia.

- Istradefylline (Nourianz™) is the main A2A antagonist, taken daily with carbidopa/[levodopa](/living-with-parkinsons/treatment/prescription-medications/levodopa "Levodopa").

- Common side effects include [dyskinesia](/understanding-parkinsons/movement-symptoms/dyskinesia "Dyskinesia"), insomnia, hallucinations and dizziness.

- Review potential medication interactions and side effects with your doctor or pharmacist.

 

   ![Woman holding several pills in her hand](/sites/default/files/styles/no_sizing/public/images/adenosinea2aantagonists.jpg?itok=NfzLcXyJ)  The basal ganglia *—* a brain circuit group that plays a role in Parkinson's disease (PD) symptoms *—* has adenosine A2A receptors located next to dopamine receptors, the target of many other Parkinson’s medications. Scientists have found that just as increasing dopamine in the basal ganglia can improve Parkinson’s symptoms, blocking the adenosine A2A receptor may have a similar effect. Since adenosine A2A blocking drugs (antagonists) do not act directly on dopamine receptors, they may be able to reduce [“off” time](/library/fact-sheets/managing-off-time "Managing "Off" Time in Parkinson's") (changes in the ability to move as a levodopa dose wanes) by 30 to 60 minutes per day without worsening dyskinesia. However, dyskinesia can still be a side effect. Reduction in “off” time should be seen by four weeks.

  ##  Forms of Adenosine A2A Antagonists 

 - ###   Istradefylline (NOURIANZ™)   
    
    **Available Doses:** 20 mg, 40 mg
    
    **Typical Treatment Regimen**: 20 to 40 mg once per day
    
    **Common Side Effects**: Dyskinesia, insomnia, hallucinations, dizziness
    
    **Indications for Usage**: Combination therapy with carbidopa/levodopa for “off” episodes
    
    People who smoke the equivalent of 20 cigarettes per day or more will require a higher dose (40 mg) of medication. This is because the cigarettes cause the liver to increase the breakdown of (metabolize) Nourianz™, making the medication less effective. It should be taken upon wakening to reduce the chance of causing insomnia.
 
 - ###   Disclaimers   
    
    Please note that the side effects listed are the most *commonly experienced*. Not all individuals will experience such side effects Careful adjustments to dosage or the timing of individual doses can often effectively limit or eliminate side effects for many people.
    
    Speak to your doctor immediately if you experience and side effects. For a complete description of possible side effects, please request a “package insert” from your pharmacist for each drug used. **It is recommended that all prescriptions be filled at the same pharmacy to avoid interactions between medications.** Interactions can be dangerous and even life-threatening, so make sure the pharmacist knows of all medications and supplements being taken, including over-the-counter medications and supplements.
    
    **Caution:** Parkinson’s medications may have interactions with certain foods, other medications, vitamins, herbal supplements, over-the-counter cold pills and other remedies. Anyone taking a PD medication should talk to their doctor and pharmacist about potential drug interactions.
 
 *Page reviewed by Dr. Chauncey Spears, Clinical Assistant Professor and Dr. Amelia Heston, Movement Disorders Fellow at the University of Michigan.*

  ##  Related Materials 

   Books 

###  [ Medications: A Treatment Guide to Parkinson’s Disease ](/library/books/medications) 



 [Read Now](/library/books/medications)

   Podcasts 

###  [ Episode 96: PD Medications and Side Effects ](/library/podcast/96) 



 [Listen Now](/library/podcast/96)

    

  ##  Related Blog Posts 

   ![Couple buying medication in a store](/sites/default/files/styles/500x360/public/images/pdmednew-bloghero.png?h=ed9ce7df&itok=xE6j_DbB)  

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###  [ PD and Medication: What's New? ](/blog/tips/2019-medication-update) 

 

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###  [ Symptom Management: Is it PD, Medication or Aging? ](/blog/awareness/aging) 

 

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 ###  Order a Parkinson’s Hospital Safety Guide 

 The Hospital Safety Guide is a resource for people with Parkinson's and their care partners filled with useful tools and information to prepare for and navigate a hospital stay.

 [ORDER NOW](/resources-support/pd-library/order-publications) 

 [LEARN MORE](/resources-support/hospital-safety-guide) 

 

 

 

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