Levodopa or a dopamine agonist?
For many years, levodopa has been the drug of choice for treating early Parkinson's disease. Although many newer drugs have been developed, including the dopamine agonists (pramipexole and ropinirole), levodopa is still considered the most effective drug for relieving the widest range of symptoms.1 It helps reduce tremor, stiffness, and slowness, and helps improve muscle control, balance, and walking.
When dopamine agonists are used alone, they are helpful in relieving most symptoms of early Parkinson's disease, especially those that affect motor function (such as stiffness and slowness). They are not as effective as levodopa in controlling tremor and other symptoms, and they tend to have more short-term side effects than levodopa.
However, it also is well documented that most people who take levodopa develop motor problems (motor fluctuations) within 5 to 10 years after starting the medicine. These complications—unpredictable swings in motor control between doses and uncontrollable jerking or twitching (dyskinesias)—can be difficult to manage and can become as disabling as some of the problems caused by the disease itself. For reasons that are not yet clear, this pattern of motor fluctuations may occur less often with the dopamine agonists, although it still occurs.
In an effort to delay the development of motor fluctuations, many doctors are now starting people with early Parkinson's disease on a dopamine agonist rather than the more traditional levodopa. A dopamine agonist may be used until it no longer adequately relieves symptoms, at which point the person starts taking levodopa in addition to the dopamine agonist.1 (Dopamine agonists can also cause severe sleep problems and hallucinations in some people; developing these side effects may be another reason to switch to levodopa.) As long as the person's symptoms are adequately controlled and he or she can tolerate the drug, dopamine agonists may be a good choice for treating early Parkinson's disease.
This approach is being used particularly in younger people with Parkinson's disease because it can delay the need for levodopa and thus may postpone the motor fluctuations that occur with long-term levodopa therapy. The American Academy of Neurology now recommends this course of treatment for most people with early Parkinson's disease, regardless of their age. One study found that people who started treatment with ropinirole (Requip), a dopamine agonist, were much less likely to develop dyskinesias and had a more predictable level of motor performance than those who took levodopa, although this drug was not as good for controlling motor symptoms as levodopa.2
Still, most people with Parkinson's disease eventually need to take levodopa to control their symptoms, even if they initially begin treatment with a dopamine agonist. Levodopa continues to offer the strongest and most immediate relief of Parkinson's symptoms.
As the disease progresses and motor fluctuations become more severe, medicines may be used together, and your doctor may change the amount and type of medicines you are taking.
Initial treatment with either drug (levodopa or a dopamine agonist) should be started only when symptoms begin to significantly affect a person's work or daily activities.1
| Author: | Monica Rhodes | Last Updated: December 13, 2006 |
| Medical Review: | E. Gregory Thompson, MD - Internal Medicine Colin Chalk, MD, CM, FRCPC - Neurology | |
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