How is Parkinson’s disease treated?
There is no cure for Parkinson’s disease. However, medications and other treatments can help relieve some of your symptoms. Exercise can help your Parkinson’s symptoms significantly. In addition, physical therapy, occupational therapy and speech-language therapy can help with walking and balance problems, eating and swallowing challenges and speech problems. Surgery is an option for some patients.
What medications are used to treat Parkinson’s disease?
Medications are the main treatment method for patients with Parkinson’s disease. Your doctor will work closely with you to develop a treatment plan best suited for you based on the severity of your disease at the time of diagnosis, side effects of the drug class and success or failure of symptom control of the medications you try.
Medications combat Parkinson’s disease by:
- Helping nerve cells in the brain make dopamine.
- Mimicking the effects of dopamine in the brain.
- Blocking an enzyme that breaks down dopamine in the brain.
- Reducing some specific symptoms of Parkinson’s disease.
Levodopa: Levodopa is a main treatment for the slowness of movement, tremor, and stiffness symptoms of Parkinson’s disease. Nerve cells use levodopa to make dopamine, which replenishes the low amount found in the brain of persons with Parkinson’s disease. Levodopa is usually taken with carbidopa (Sinemet®) to allow more levodopa to reach the brain and to prevent or reduce the nausea and vomiting, low blood pressure and other side effects of levodopa. Sinemet® is available in an immediate release formula and a long-acting, controlled release formula. Rytary® is a newer version of levodopa/carbidopa that is a longer-acting capsule. The newest addition is Inbrija®, which is inhaled levodopa. It is used by people already taking regular carbidopa/levodopa for when they have off episodes (discussed below).
As people have Parkinson’s for a longer amount of time, the effects of their levodopa doses don't last as long as they did before, resulting in their symptoms (tremor, muscle rigidity, slowness) worsening before they are due to take their next dose. This is called ‘wearing off.’ They may also notice involuntary, fluid, dancing or fidgeting-like movements of their body called dyskinesias. These movements can indicate the levodopa dose is too high. These ups and downs of the effects of levodopa are called motor fluctuations and are often improve with adjustment of the medication by the neurologist.
Dopamine agonists: These drugs mimic the effects of dopamine in your brain. They are not as effective as levodopa in controlling slow muscle movement and muscle rigidity. Your doctor may try these medications first and add levodopa if your symptoms are not well controlled depending on severity of your symptoms and your age.
Newer dopamine medications include ropinirole (Requip®) and pramipexole (Mirapex®). Rotigotine (Neupro®) is given as a patch. Apomorphine (Apokyn®) is a short-acting injectable medication.
Side effects of dopamine agonists include nausea, vomiting, dizziness, lightheadedness, sleeping problems, leg swelling, confusion, hallucinations and compulsive behavior (such as excessive gambling, buying, eating, or sex). Some of these side effects are more likely to occur in people over 70 years old.
Catechol O-methyltransferase (COMT) inhibitors: These drugs block an enzyme that breaks down dopamine in your brain. These drugs are taken with levodopa and slow your body’s ability to get rid of levodopa, so it lasts longer and is more reliable. Entacapone (Comtan®) and tolcapone (Tasmar®) are examples of COMT inhibitors. Opicapone (Ongentys®) is the newest medication in this class, receiving FDA approval in April 2020. Because these drugs increase the effectiveness of levodopa, they may also increase its side effects, including involuntary movements (dyskinesia). Tolcapone is rarely prescribed because it can damage the liver and requires close monitoring to prevent liver failure.
MAO B inhibitors. These drugs block a particular brain enzyme – monoamine oxidase B (MAO B) – that breaks down dopamine in your brain. This allows dopamine to have longer lasting effects on the brain. Examples of MAO B inhibitors include selegiline (Eldepryl®, Zelapar®), rasagiline (Azilect®) and safinamide (Xadago®). Side effects of these drugs include nausea and insomnia. Giving carbidopa-levodopa with an MAO B inhibitor increases the chance of hallucinations and dyskinesia. MAO B inhibitors are not prescribed if you are taking certain antidepressants or narcotic medications. Your doctor will review all your current medications and make the best treatment choice for you.
Anticholinergics. These drugs help reduce tremor and muscle stiffness. Examples include benztropine (Cogentin®) and trihexyphenidyl (Artane®). These are the oldest class of drugs to treat Parkinson’s disease. Side effects include blurred vision, constipation, dry mouth and urine retention. Persons over age 70 who are prone to confusion and hallucinations or have memory impairment should not take anticholinergics. Because of the high rate of side effects these medications are less commonly used.
Amantadine. Amantadine (Symmetrel®), first developed as an antiviral agent, is useful in reducing the involuntary movements (dyskinesia) caused by levodopa medication. There are two extended-release forms of the drug, Gocovri®, and Osmolex ER®. Side effects include confusion and memory problems.
Istradefylline. Istradefylline (Nourianz®) is an adenosine A2A receptor antagonist. It is used for people taking carbidopa-levodopa but experiencing off symptoms. Like the other drugs that act to increase the effectiveness of levodopa, they may also increase its side effects, including involuntary movements (dyskinesia) and hallucinations.
What are the surgical treatments for Parkinson’s disease?
Most patients with Parkinson’s disease can maintain a good quality of life with medications. However, as the disease worsens, medications may no longer be effective in some patients. In these patients, the effectiveness of medications becomes unpredictable – reducing symptoms during “on” periods and no longer controlling symptoms during “off” periods, which usually occur when the medication is wearing off and just before the next dose is to be taken. Sometimes these variations can be managed with changes in medications. However, sometimes they can’t. Based on the type and severity of your symptoms, the failure of adjustments in your medications, the decline in your quality of life and your overall health, your doctor may discuss some of the available surgical options.
- Deep brain stimulation (DBS) involves implanting electrodes in the brain, which deliver electrical impulses that block or change the abnormal activity that cause symptoms. DBS can treat most of the major movement symptoms of Parkinson’s disease such as tremor, slowness of movement (bradykinesia) and stiffness (rigidity). It does not improve memory, hallucinations, depression, and the other non-movement symptoms of Parkinson’s disease. Only patients whose symptoms are not controlled despite medication trials and who meet other strict criteria may be candidates for DBS. Your doctor will discuss if this is the right treatment for you.
- Carbidopa-levodopa infusion involves the surgical placement of a feeding tube into the small intestine. A gel form of the medication carbidopa-levodopa (Duopa®) is delivered through this tube. This method of continuous infusion of the drug keeps a stable dosage in the body. This helps patients who have had variation in their response to the oral form of carbidopa-levodopa but are still benefitting from the combination drug.
- Pallidotomy involves destroying a small portion of a part of the brain that controls movement (the globus pallidus). Pallidotomy help reduce involuntary movements (dyskinesias), muscle stiffness and tremor.
- Thalamotomy involves destroying a small part of the thalamus. This may help a small number of patients who have severe tremors of their arm or hand.