Common Medications for Parkinson’s Disease

Medically reviewed by Femi Aremu, PharmD

Parkinson’s disease is a condition that damages dopamine-producing brain cells, leading to tremors, stiffness, and difficulty with balance and coordination.

Medications for Parkinson’s disease aim to rebalance dopamine levels and improve movement and other complications of the disease. Healthcare providers may prescribe levodopa, dopamine agonists, anticholinergics, catechol-o-methyltransferase (COMT) inhibitors, and type-B monoamine oxidase (MAO-B) inhibitors to manage symptoms.

This article will review the commonly prescribed medications for Parkinson's disease.

What Medications Help Treat Parkinson’s Disease?

To manage Parkinson’s disease, healthcare providers prescribe various types of drugs.

Levodopa is one such drug that replaces the lost dopamine. There are also dopamine agonists that mimic the effects of dopamine, COMT inhibitors that increase the duration of action of levodopa, and MAO-B inhibitors that help prevent the breakdown of dopamine.

In addition to the primary treatments for Parkinson’s disease, other medications can help manage specific symptoms, including:

• Anticholinergics for controlling tremors

• Amantadine to manage uncontrolled movement

• Exelon (rivastigmine) for mild to moderate dementia associated with Parkinson’s disease

• Nourianz (istradefylline) to manage “wearing-off” episodes, wherein people with Parkinson's experience muscle stiffness and loss of muscle control

Levodopa and Carbidopa

Carbidopa/levodopa is a combination medication sold under the brand name Sinemet.

Levodopa is a prodrug, meaning that it is a precursor of dopamine. It works by replacing the dopamine lost in Parkinson’s disease. Carbidopa is given with levodopa to prevent it from breaking down before it crosses the blood-brain barrier.

Levodopa is considered the most effective agent for Parkinson’s disease. People who use levodopa long term sometimes experience movement complications, which are referred to as dyskinesia. You can manage this side effect by adjusting your medication regimen.

Dopamine Agonists

Dopamine agonists are a class of medications that act similarly to dopamine at the dopamine receptor. They are commonly prescribed as an initial treatment option for younger people.

As the disease advances, most individuals will require multiple therapies and, therefore, will eventually take dopamine agonists. However, not all dopamine agonists are appropriate for treating Parkinson’s disease.

Some examples of dopamine agonists for treating Parkinson’s disease are:

• Mirapex (pramipexole)

• Ropinirole

• Neupro (rotigotine)

• Apokyn (apomorphine)

Though generally well tolerated, the following side effects are possible:

• Compulsive behaviors

• Sleep problems

• Confusion

• Leg swelling and discoloration

• Movement disorders

• Lightheadedness

Stopping dopamine agonists suddenly can result in a condition called dopamine withdrawal syndrome, which can bring on symptoms such as apathy.

Anticholinergics

Anticholinergic medications are primarily for treating tremors. They also treat other symptoms of Parkinson’s disease, such as rigidity, excessive drooling, and excessive sweating.

Healthcare providers usually prescribe them as an initial treatment option for younger people, but their significant side effects make them less suitable for older adults (65 and over) due to the risk of adverse reactions. These side effects include:

• Dry mouth

• Constipation

• Urinary retention

• Blurred vision

• Drowsiness

• Confusion

Examples of anticholinergics include:

• Benztropine

• Trihexyphenidyl

• Levsin (hyoscyamine)

Anticholinergics can be taken alone or with levodopa or dopamine agonists.

COMT Inhibitors

COMT inhibitors are taken with levodopa to increase the latter's duration of action. They help manage "wearing off" episodes at the end of levodopa doses, which occur when Parkinson's symptoms, such as muscle stiffness and loss of muscle control, return between doses of medication.

COMT inhibitors work by blocking levodopa metabolism by inhibiting the enzyme catechol-o-methyltransferase (COMT).

Their side effects can include:

• Uncontrolled movements

• Confusion or hallucinations

• Nausea or diarrhea

• Orange-colored urine

• Low blood pressure

Examples include:

• Comtan (entacapone)

• Tasmar (tolcapone)

• Ongentys (opicapone)
  

MAO-B Inhibitors

Selective MAO-B inhibitors work by preventing the breakdown of dopamine to increase its activity. They are usually prescribed in combination with carbidopa and levodopa.

These medications are usually for treating "wearing off" episodes from levodopa in combination with other Parkinson's disease drugs. Only selegiline and rasagiline may be taken alone as an initial treatment for people with mild motor symptoms.

Side effects of MAO-B inhibitor can include:

• Nausea

• Headache

• Trouble falling asleep

• Confusion in older adults (often with selegiline)

Examples include:

• Zelapar (selegiline) oral disintegrating tablet

• Azilect (rasagiline)

• Xadago (safinamide)
  

Other Medications

Amantadine is a medication prescribed for managing dyskinesias and tremors. It's an N-methyl-D-aspartate (NMDA) receptor inhibitor that works by blocking dopamine reuptake and increasing dopamine release.

Gocovri (amantadine) is an extended-release version of amantadine prescribed alongside levodopa to improve movement.

Nourianz (istradefylline) is sometimes prescribed alongside carbidopa and levodopa. Although its exact mechanism of action is unknown, it is believed to block adenosine receptors. It is specifically prescribed to treat "wearing-off" episodes. Though not all people with Parkinson's experience these episodes, it's more common with those who have taken levodopa for many years.

Exelon (rivastigmine) is prescribed for managing mild to moderate dementia caused by Parkinson’s disease. It works by reversibly binding to and inactivating acetylcholinesterase. Acetylcholinesterase is the enzyme that breaks down acetylcholine, an essential neurotransmitter for memory.

Stalevo (carbidopa, levodopa, and entacapone) is a combination of three medications. Levodopa replaces the dopamine lost to the disease, while carbidopa prevents the premature breakdown of levodopa. Entacapone, on the other hand, is a COMT inhibitor that increases how long levodopa works when taken in combination with it.

Summary

Parkinson’s disease affects the cells in the brain that produce dopamine, leading to problems with movement and thinking. There are different types of medications for treating Parkinson’s disease. These include levodopa, dopamine agonists, anticholinergics, COMT inhibitors, and MAO-B inhibitors.

Levodopa helps replace dopamine, dopamine agonists mimic the effects of dopamine, COMT inhibitors help levodopa work for longer, and MAO-B inhibitors help prevent the breakdown of dopamine.

Other medications that can treat Parkinson’s disease include amantadine, Exelon, Nourianz, and Stalevo.

Frequently Asked Questions

Is it safe to drink alcohol while taking medication for Parkinson’s disease?

No, it is not recommended to drink alcohol while on medication for Parkinson’s disease. Alcohol can worsen common side effects of Parkinson's medication, such as dizziness and sleepiness. This can lead to falls and injuries, especially in older adults, who are already at risk for these types of accidents.

Alcohol can also worsen tremors associated with Parkinson’s disease. Therefore, avoiding alcohol altogether while taking medication for Parkinson’s disease is best. If you have any questions or concerns about consuming alcohol while on medication for Parkinson’s disease, speak with your healthcare provider or pharmacist.

Will changing my diet help manage Parkinson’s symptoms?

A nutritionist may recommend the Mediterranean diet, which is rich in vegetables, fruits, legumes, whole grains, nuts, and fish and low in saturated fat. These foods are known for their antioxidant and anti-inflammatory properties, which can help to reduce the risk of developing Parkinson’s disease and slow down the progression of its symptoms.

Will medication help stop Parkinson-related tremors?

In the early stages of Parkinson’s disease, tremors can occur while resting, which is often the first noticeable symptom. Typically, they start in one hand or foot on one side of the body and then spread to both sides. Initially, the tremors may be the only symptom treated to delay the need for stronger medications. Healthcare providers may prescribe anticholinergics (benztropine and trihexyphenidyl) and amantadine (in younger people) to treat tremors. In addition, a selective MAOI inhibitor may also be prescribed as a treatment option.

Read the original article on Verywell Health.