Medications
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.5 However, because long-term use of levodopa at high dosages often leads to motor complications that can be difficult to manage, sometimes doctors use the newer dopamine agonists (such as pramipexole and ropinirole) to treat 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. But dopamine agonists have more side effects and don't control symptoms as well as levodopa. And in the long-term, the same amount of people have motor complications no matter what medicine is used first.1
The question of whether it is better to use levodopa or a dopamine agonist as initial treatment has not been fully resolved. The choice will most likely be different for each person. Levodopa controls symptoms more effectively than dopamine agonists in most people. And levodopa has fewer side effects than dopamine agonists. But 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. It is important to work with your doctor to find the medicines that work the best for you.
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. 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
All drugs used to treat Parkinson's disease can cause unpleasant side effects. An ideal drug regimen controls your symptoms without causing side effects that you cannot tolerate. Doctors generally will try one drug at a time, starting with low doses, to minimize side effects.
Increasing, decreasing, or stopping the medicines you are taking may cause big changes in your symptoms and can be dangerous. Even if a medicine doesn't seem to be working, you may have an increase in the symptoms of Parkinson's disease when you stop taking it.
Early in the disease, it might be helpful to take pills with food to help with nausea, which may be caused by some medicines taken for Parkinson's disease. Later in the disease, taking the medicines at least one hour before meals (and at least two hours after meals) may help them work best. Some medicines for Parkinson's disease don't work as well if you take them at the same time you eat food with protein in it, such as meat or cheese. The protein can block the medicine and keep it from working as well as it should.
Long-term use of Parkinson's disease medicines can cause motor fluctuations. These include sudden changes in your response to the drug (called the on-off response) and involuntary twitching and writhing movements (dyskinesias).
A possible serious side effect of taking medicines for Parkinson's disease is excessive daytime sleepiness. Sudden and overwhelming sleepiness without awareness of falling asleep is often referred to as a "sleep attack." These attacks, especially if they occur while driving, can pose a great threat to people with Parkinson's disease. Talk to your doctor about the dangers of driving while taking these drugs.
Drugs for Parkinson's disease can also cause risk-taking behavior such as uncontrollable gambling and shopping and an inappropriate increase in sexual activity. These changes in behavior can be very upsetting and difficult for family and friends to understand. If you or a family member sees this kind of behavior in you, talk to your doctor about it right away.
Changing the amount of the drug and using combinations of different drugs may help to manage these problems.