Parkinson’s is best known for causing symptoms related to movement (known as “motor symptoms”), such as tremors, muscle stiffness, slow movement (bradykinesia), and impaired balance. But it can also cause nonmotor, or nonmovement, symptoms, such as dementia; psychosis, or loss of contact with reality; mood disorders such as depression, anxiety, and apathy; and sleep disorders such as insomnia. Many of the symptoms of Parkinson’s are the result of a loss of neurons in the brain that produce the neurotransmitter (or chemical messenger) dopamine. Not surprisingly then, many of the treatments for Parkinson’s disease either raise the level of dopamine in the brain or attempt to mimic its effect. Medications for Parkinson’s disease fall into three general categories:

Medications that increase the level of dopamine in your brainMedications that affect other neurotransmitters, to help control motor symptomsMedications that help control nonmotor symptoms

Dopamine-Like Medication

Sometimes referred to simply as levodopa, or L-DOPA, the drug eventually becomes dopamine that your brain can use. Dopamine can’t be taken directly as a treatment because it’s broken down in the body before it reaches the brain. Other possible side effects of levodopa include nausea, vomiting, sleepiness, and orthostatic hypotension, or low blood pressure that occurs when standing up after sitting or sitting up after lying down. The AAN practice guidelines note that in early Parkinson’s, taking levodopa with meals may decrease nausea, but in later stages of the disease, doing so may decrease the drug’s therapeutic efficacy.

Dopamine Agonists

These medications mimic the action of dopamine in the brain and can have side effects similar to those of levodopa. They may be taken alone or with levodopa. According to the new AAN guidelines for treating early Parkinson’s, dopamine agonists are more likely than levodopa to cause impulse control disorders, excessive daytime sleepiness, and sleep attacks. They may also be more likely to cause hallucinations. And, like levodopa, they can contribute to orthostatic hypotension. Still, individual characteristics such as body size, sex, and disease severity also influence the likelihood of experiencing certain drug side effects, which is why people who are in the early stages of Parkinson’s disease should talk with their doctor about the potential benefits and risks of these medications before starting any of them.

MAO-B Inhibitors

Sometimes, an MAO-B inhibitor is taken with levodopa to prolong the effect of that drug. However, taking these drugs at the same time as certain antidepressants and sedatives should be avoided or monitored closely by your doctor because of potentially dangerous interactions. Common side effect of MAO-B inhibitors include mild nausea, dry mouth, lightheadedness, and constipation. The AAN practice guidelines note that MAO-B inhibitors are less effective than levodopa at improving mobility in early Parkinson’s and are additionally associated with a higher risk of drug discontinuation because of side effects. Your doctor can help you decide whether this kind of medication is a good choice for you.

COMT Inhibitors

This group of drugs includes Comtan (entacapone), Ongentys (opicapone), and Tasmar (tolcapone). The most common side effect of COMT inhibitors is diarrhea. They may also cause sleep disturbances, dizziness, or hallucinations. Tasmar has been shown to cause severe liver disease in some people, so you may need to undergo regular blood tests to assess your liver function if you take it.

Symmetrel (Amantadine)

Symmetrel (amantadine) is an antiviral medication that may increase the effects of dopamine in the brain. Researchers are unsure why amantadine helps in this area. Amantadine is sometimes taken by itself early in the course of Parkinson’s disease. It may also be taken later on to help with dyskinesia caused by levodopa.

Anticholinergics

Anticholinergics can be helpful for reducing tremor and dystonia associated with “wearing off.” They work by reducing the action of acetylcholine, a neurotransmitter involved in activating muscles. This group of drugs includes Artane (trihexyphenidyl), Cogentin (benztropine), Scopace (scopolamine), and Parsidol (ethopropazine).

Antipsychotics

Often, adjusting the doses of certain other Parkinson’s medications will also help with these symptoms. However, many traditional antipsychotic medications like Haldol (haloperidol) and Risperdal (risperidone) can worsen symptoms of Parkinson’s disease because they work by blocking dopamine.

Antidepressants

Before prescribing an antidepressant, your doctor will want to know about any herbal supplements that you take, as well as any drug and alcohol use, since antidepressants may interact with these substances (and with some drugs for Parkinson’s disease).

Stimulants

If a sleep disorder persists in spite of efforts to address underlying causes (like pain or frequent urination), then your doctor may prescribe a medication like Provigil (modafinil) to reduce sleepiness during the day.

Cholinesterase Inhibitors

Medications like Aricept (donepezil), Exelon (rivastigmine), Namenda (memantine), and Razadyne (galantamine) were developed for Alzheimer’s disease, but they may also help with dementia in people with Parkinson’s.

Estrogen

Although research on the effects of estrogen hormone replacement therapy (HRT) among women with Parkinson’s is limited, no studies thus far have shown any harm in taking HRT alongside standard Parkinson’s medications. Estrogen alone is not considered a treatment for Parkinson’s. The APDA funds educational efforts, research, and patient services for Parkinson’s disease. You could join a local chapter if you’re interested in getting involved in a support group, exercise class, or another resource in your area. Davis Phinney Foundation for Parkinson’s The mission of this foundation is to help people with Parkinson’s live well. If you’re a patient or caregiver, check out its Live Well TODAY webinar series for more information about living well with Parkinson’s. European Parkinson’s Disease Association (EPDA) The EPDA is the leading Parkinson’s organization in Europe. It provides free resources, such as at-home workouts geared toward people with Parkinson’s. The Michael J. Fox Foundation for Parkinson’s Research The actor Michael J. Fox, who was diagnosed with young-onset Parkinson’s disease in 1991, later established The Michael J. Fox Foundation for Parkinson’s Research in 2000. The foundation offers many resources, including the Parkinson’s 360 guide for living with Parkinson’s, and the Fox Trial Finder for those interested in joining a clinical trial. Parkinson’s Foundation This foundation aims to empower people with Parkinson’s by funding care- and treatment-related research. If you need more information about Parkinson’s or a referral to a health professional, call the foundation’s helpline at 800-4PD-INFO (800-473-4636). The helpline is staffed by social workers, nurses, and health educators. Learn More About Additional Resources and Support for Parkinson’s Disease