What Other Drugs Are Used to Treat Parkinson's?

Reviewed by: HU Medical Review Board | Last reviewed: January 2023

Parkinson's disease (PD) is a chronic, progressive disease that affects nerve cells in the body and brain. PD causes a number of motor (those that affect how the body moves) and non-motor symptoms.

While there is no known cure for PD, there are drugs available that can help manage symptoms. Treatment is customized to each person's needs based on their symptoms, as well as the risks and benefits of each medicine.

Many of the drugs used to treat PD work to lessen motor symptoms. This includes tremor, rigidity, impaired balance, and loss of spontaneous movement.1

These symptoms are caused by changes in the amount of dopamine in the brain. Dopamine is a chemical messenger that helps our body make smooth, purposeful movement. PD damages the neurons in the brain that make dopamine.1

Many PD drugs work to treat motor symptoms by replacing, copying, or enhancing the effect of dopamine in the brain. These drugs include:1

What are non-motor symptoms?

Symptoms caused by PD that are not related to movement are called non-motor symptoms. This may include symptoms like:1-4

  • Low blood pressure upon changing positions or standing (orthostatic hypotension)
  • Memory and thinking (cognitive) changes, including memory difficulties, slowed thinking, and dementia
  • Mood changes, such as depression and anxiety
  • Sleep problems, such as difficulty falling or staying asleep
  • Digestive issues, such as constipation and nausea
  • Increased sweating
  • Sudden, frequent outbursts of crying or laughing that cannot be controlled (pseudobulbar affect, or PBA)
  • Drooling
  • Pain
  • Hallucinations

Non-motor symptoms are very common in PD. One study found that 90 percent of people with PD reported at least 1 non-motor symptom. These symptoms may be more troublesome and disabling than motor symptoms.1

How do these other drugs work?

Every drug on this page works differently. Some have been approved by the US Food and Drug Administration (FDA) to treat non-motor symptoms in people with PD.2

Some have been approved for the general population but have not been well-studied in large numbers of people with PD. However, doctors commonly prescribe these drugs, and many people with PD often find that they improve their non-motor symptoms.2

Drugs to treat non-motor symptoms

There are a number of drugs available to treat non-motor symptoms of PD. Treatment is specific to the symptoms each person has. Drugs commonly prescribed include:1-9

  • Northera® (droxidopa) and OrvatenⓇ (midodrine) – Both of these drugs are used to treat orthostatic hypotension. Doctors usually first try to treat low blood pressure with lifestyle and dietary changes like salt supplementation, exercise, and increased fluid intake. If those methods do not work, they may prescribe 1 of these drugs.
  • Exelon® (rivastigmine) – Exelon drug is FDA-approved to treat mild to moderate PD dementia. It is 1 of the most frequently prescribed drugs to treat symptoms of cognitive impairment in PD.
  • Nuedexta® (dextromethorphan and quinidine) – Nuedexta is used to treat involuntary outbursts of laughing or crying, a condition known as PBA. It is usually prescribed to people with amyotrophic lateral sclerosis (ALS or Lou Gehrig's disease) or multiple sclerosis (MS). However, doctors may prescribe it off-label to people with PD.
  • Nuplazid® (pimavanserin) – Nuplazid was approved in 2016 as the first drug specifically designed to treat hallucinations and delusions in people with PD. It may also improve nighttime sleep and daytime wakefulness.
  • Nourianz® (istradefylline) – Nourianz is used as an add-on treatment to carbidopa/levodopa to help during "off" episodes. These are periods when a person's medicines are not working as well, causing an increase or worsening of PD motor symptoms.

What are the possible side effects?

Side effects can vary depending on the specific drug you are taking.

Common side effects of Northera and Orvaten include:1-6

  • Headache
  • Dizziness
  • Nausea
  • High blood pressure
  • Chills
  • Frequent or urgent urination
  • Rash
  • Numbness and tingling

Both Northera and Orvaten have boxed warnings, the strictest warning from the FDA. They have this warning because they can raise blood pressure and increase the risk of elevated blood pressure after lying down after standing or sitting (supine hypertension). This can lead to strokes, heart attacks, and death.5,6

Common side effects of Exelon include:1-3,7

  • Nausea and vomiting
  • Diarrhea
  • Decreased appetite
  • Weight loss
  • Increased tremor

Common side effects of Nuedexta include:4

  • Diarrhea and gas
  • Vomiting
  • Cough
  • Dry eyes or mouth
  • Weakness
  • Muscle spasms

Common side effects of Nuplazid include:1-3,8

  • Nausea
  • Swelling of hands, ankles, or feet
  • Confusion

Nuplazid has a boxed warning as well. It has this warning because older adults with dementia-related psychosis treated with antipsychotic drugs are at an increased risk of death.8

Common side effects of Nourianz include:1,9

  • Dizziness
  • Constipation
  • Appetite loss
  • Insomnia

Many different types of drugs are used to treat non-motor symptoms of PD, and none cause all of these side effects.

These are not all the possible side effects of these drugs. Talk to your doctor about what to expect when taking these drugs. You also should call your doctor if you have any changes that concern you when taking drugs to treat non-motor symptoms of PD.

Other things to know

Some common non-motor symptoms of PD, such as constipation or sleep issues, may be a side effect of drugs used to treat motor symptoms. People taking drugs to treat the motor symptoms of PD should talk to their doctor about the side effects they experience. Changing these drugs can improve some non-motor symptoms.1

Drugs used to treat some non-motor symptoms can interact with drugs used to control motor symptoms. This can cause unwanted or harmful side effects. It is important for people with PD to see a neurologist who understands how these drugs work together.

Before beginning treatment for PD, tell your doctor about all your health conditions and any other drugs, vitamins, or supplements you take. This includes over-the-counter drugs.

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