Medicines are the most common treatment for Parkinson's disease. The goal is to correct the shortage of the brain chemical (neurotransmitter) dopamine, which causes the symptoms of Parkinson's disease. Treatment with drugs is usually started when symptoms become disabling or disrupt a person's daily activities.

Treatments may differ based on a person's symptoms and age and how the person responds to a certain drug. Drugs often improve symptoms, but they also may cause side effects. It may take some time to find the best combination of drugs for a particular person.

Currently, levodopa is considered the most effective drug for controlling symptoms of Parkinson's disease and for many years was the preferred drug for treating newly diagnosed people.⁶ However, because long-term use of levodopa at high dosages often leads to motor complications that can be difficult to manage, many doctors are using the newer dopamine agonists (such as pramipexole and ropinirole) to treat some people during the early stages of Parkinson's disease. Using these drugs in the early stages of the disease may allow treatment with levodopa to be delayed, thus postponing the onset of levodopa-related motor problems.³ However, using a dopamine agonist may also lead to motor complications.

The question of whether it is better to use levodopa or a dopamine agonist as initial treatment has not been fully resolved. Levodopa controls symptoms more effectively than dopamine agonists in most people. However, based on a growing body of evidence, concern about the long-term effects of early and high-dose levodopa use is leading some experts to recommend initial treatment with dopamine agonists, especially in people who are younger than 60. As the disease progresses, your doctor may also prescribe levodopa along with a dopamine agonist.

Apomorphine (Apokyn) is a fast-acting dopamine agonist used for treating occasional episodes of immobility associated with Parkinson's disease. Apomorphine can be injected under the skin when muscles become "stuck" or "frozen" and you are unable to rise from a chair or perform daily activities. Treatment with "as needed" apomorphine shots may make it possible to decrease the doses of other medicines you are taking for Parkinson's disease. This may reduce the risk of side effects, such as twitching and other uncontrolled movements. Work with your doctor to decide the right combination of medicines and doses for you. It may also be possible to take a regular dose of levodopa and a dopamine agonist, supplemented with apomorphine shots when needed instead of regularly adjusting the dose of oral drugs.⁵ Apomorphine can be taken with an antinausea drug to prevent side effects of severe nausea and vomiting.

Medication Choices

Several drugs may be used to treat Parkinson's disease at different stages of the disease.

In general, treatment of early Parkinson's starts with:

• Levodopa and carbidopa.
• Dopamine agonists (bromocriptine, pramipexole, ropinirole).
• COMT inhibitors (entacapone, tolcapone).
• MAO-B inhibitors (rasagiline, selegiline).
• Amantadine.
• Anticholinergic agents (benztropine, trihexyphenidyl).

What To Think About