Dopamine agonists directly stimulate the
receptors in nerves in the brain that normally would be stimulated by
dopamine. Unlike levodopa, a dopamine agonist is not
changed (converted) into dopamine when it enters the body, but it behaves like
Dopamine agonists may be used in the
early stages of
Parkinson's disease to reduce symptoms. This approach
is often effective in people who have been newly diagnosed with the disease
(especially those younger than 60), because it can delay the need for levodopa
and thus postpone the motor fluctuations that may occur with long-term levodopa
A dopamine agonist may be added to treatment with
levodopa in the later stages of Parkinson's disease when:
Apomorphine is an injectable,
rapid-acting dopamine agonist. It is injected into the skin during occasional
episodes of immobility when muscles become "stuck" or "frozen," and you are
unable to rise from a chair or perform daily activities. Treatment with
apomorphine is referred to as "rescue" therapy, because it is used during
periods when levodopa or other dopamine agonists are not effective or have worn
When used alone in early
Parkinson's disease, dopamine agonists may reduce
symptoms of the disease, especially those that affect motor function, such as
stiffness and slowness. Although they are not as effective as levodopa in
controlling symptoms, they have the benefit of postponing the need for levodopa
therapy. This in turn may help delay the onset of levodopa-related motor
When taken in combination
with levodopa, dopamine agonists may:1
Because apomorphine is rapid-acting, it is usually effective within 10
minutes from the time of injection. It works for approximately 60 to
All medicines have side effects. But many people don't feel the side effects, or they are able to deal with them. Ask your pharmacist about the side effects of each medicine you take. Side effects are also listed in the information that comes with your medicine.
Here are some important things to think about:
or other emergency services right away if you have:
Call your doctor right away if you have:
Common side effects of this medicine include:
See Drug Reference for a full list of side effects. (Drug
Reference is not available in all systems.)
The decision about whether it is
better to use
levodopa or a dopamine agonist as the first treatment
in Parkinson's disease is different for each person. Levodopa controls
symptoms better than dopamine agonists in most people. And levodopa has fewer
side effects than dopamine agonists. But concern about
levodopa-related motor fluctuations is leading some
doctors to use dopamine agonists as initial therapy in people with newly diagnosed Parkinson's disease in
order to delay treatment with levodopa. The American Academy of Neurology now recommends this approach for
most people who have the disease.
In theory, the purpose behind delaying treatment with levodopa, especially in
younger people with Parkinson's, is to delay the motor fluctuations that eventually occur with levodopa therapy.
But in the long term, the same amount of people have motor fluctuations no matter what medicine is used first.2
If a dopamine agonist is used as initial therapy, levodopa may be added when the dopamine agonist is no longer
able to control symptoms adequately on its own.
Apomorphine causes severe nausea and vomiting and must be
taken with anti-nausea medicine. Do not drink alcohol when you are using apomorphine.
Dopamine agonists may cause impulse-control disorders in some people. Impulse-control disorders include uncontrollable or problem gambling, sexual behavior, and shopping. Binge eating is another example.
Dopamine agonists are more likely than levodopa to cause impulse-control disorders. But your risk is even higher if you take both a dopamine agonist and levodopa. If you are concerned about taking these medicines because of this risk, talk with your doctor.
Medicine is one of the many tools your doctor has to treat a health problem. Taking medicine as your doctor suggests will improve your health and may prevent future problems. If you don't take your medicines properly, you may be putting your health (and perhaps your life) at risk.
There are many reasons why people have trouble taking their medicine. But in most cases, there is something you can do. For suggestions on how to work around common problems, see the topic Taking Medicines as Prescribed.
Follow-up care is a key part of your treatment and safety. Be sure to make and go to all appointments, and call your doctor if you are having problems. It's also a good idea to know your test results and keep a list of the medicines you take.
Complete the new medication information form (PDF)(What is a PDF document?) to help you understand this medication.
Clarke CE, Moore AP (2007). Parkinson's disease, search date November 2006. BMJ Clinical Evidence. Available online: http://www.clinicalevidence.com.
Katzenschlager R, et al. (2008). Fourteen-year final report of the randomized PDRG-UK trial comparing three initial treatments in PD. Neurology, 71(7): 474–480.
January 25, 2013
Anne C. Poinier, MD - Internal Medicine
& G. Frederick Wooten, MD - Neurology
How this information was developed to help you make better health decisions.
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