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Wednesday, July 30, 2014

Dopamine Agonists

What are the facts

  • Dopamine agonists are a different class of drugs than levodopa.
  • While levodopa is converted in the brain into dopamine, dopamine agonists actually mimic the effects of dopamine without having to be converted.
  • Dopamine agonists are often the first medication prescribed to treat PD, but can also be used in later stages of PD with carbidopa/levodopa.
The following are the most commonly prescribed dopamine agonists in the U.S. :
  • Pramipexole (Mirapex®)
    • Approved by the FDA in 1997
    • Effective in the early treatment of the motor symptoms of PD and plays an important role in controlling motor fluctuations.
  • Ropinirole (Requip®)
    • Approved by the FDA in 1997
    • Effective in the early treatment of the motor symptoms of PD and plays an important role in controlling motor fluctuations.
  • Rotigotine (Neupro® patch)
    • Formulated as a once-daily transdermal (skin) patch that is changed every 24 hours.
    • Clinical trials have shown Neupro is just as effective as the oral dopamine agonists: pramipexole and ropinirole.
    • The most common side effect is skin irritation, which is usually mild. Patients are able to tolerate the patch better when they rotate the sites where they adhere the patch.
    • Although the patch was recalled in 2008 because of a manufacturing and quality control issue, , it was reintroduced to the U.S. market in 2012, following improvements and a study of the new formulation.
  • Apomorphine (Apokyn®)
    • Apomorphine was first used to treat PD in 1950, but its use was associated with many side effects, especially nausea and vomiting.
    • In the 1990s apomorphine was released in a self-injectable form. It is now used as a “rescue” drug for people with advanced PD and severe “off” episodes.
    • It can be used as many as five times per day as a “rescue” agent.
Dopamine agonists can be used effectively as a single drug in early stages of PD or in combination with carbidopa/levodopa later on.

What are the Side Effects?

  • Excessive daytime sleepiness
  • Visual hallucinations
  • Confusion
  • Swelling of the ankles
  • Dyskinesia (not as common)
  • Compulsive behaviors (such as uncontrolled shopping, gambling, eating, and sexual urges.)
Note: Pergolide and Bromocriptine are no longer available in the U.S. as treatment for PD.
Caution: PD 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.

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