What Is Amantadine?

Reviewed by: HU Medical Review Board | Last reviewed: May 2022

Amantadine is a type of medicine used to treat some symptoms of Parkinson’s disease (PD). It is used to treat tremors and dyskinesias. Dyskinesias are uncontrollable, abnormal movements. They are a common side effect of levodopa, a long-term PD treatment. Levodopa is typically given with carbidopa and called carbidopa/levodopa.1,2

Carbidopa/levodopa is a very common and effective medicine used to treat PD. However, long-term use can cause dyskinesias. Some people are also prescribed additional drugs like amantadine to manage dyskinesias.1,3

On-off episodes

Amantadine may also reduce the changes in symptoms experienced by many people with PD. People treated with carbidopa/levodopa for a long time can have “on-off” episodes. “On” episodes happen when medicine is working and symptoms are minimal. “Off” episodes are when symptoms are more apparent. This can happen when the medicine has not yet taken effect or is wearing off.1,2

“Off” episodes can interfere with daily activities and can happen multiple times a day. During “off” episodes, people may have difficulty moving, walking, and speaking. These episodes may last from a few minutes up to a few hours.1-3

Different types

There are several different formulations of amantadine, including:1

  • Symmetrel® (amantadine) tablet
  • Gocovri® (amantadine ER) capsule
  • Osmolex™ (amantadine ER) tablet

The active ingredient is amantadine.1

How does it work?

Amantadine was first used as an antiviral drug used to treat the flu. It is now only used in people with PD. The exact way amantadine works for people with PD is not fully understood. Doctors believe it may work by increasing the amount of dopamine in certain parts of the brain. This may be how it helps reduce dyskinesias.3,4

What are the possible side effects?

The most common side effects of amantadine include:1,3,5

  • Dry mouth
  • Nausea or vomiting
  • Constipation
  • Confusion
  • Tiredness
  • Unexplained purple patches on skin

Amantadine can also cause serious side effects. Contact your doctor if you notice any of the following side effects while taking amantadine:1,3,5

  • Hallucinations (seeing things or hearing voices that do not exist)
  • Thoughts of hurting yourself or others
  • Swelling in the hands, feet, ankles, or lower legs
  • Difficulty urinating or bloody or cloudy urine
  • Fainting

These are not all the possible side effects of amantadine. Talk to your doctor about what to expect when taking amantadine. You also should call your doctor if you have any changes that concern you when taking amantadine.

Other things to know

Amantadine comes in an extended-release and standard formula. Gocovri and Osmolex are both extended-release formulas. They are usually only taken once a day, unlike Symmetrel.1,5

Extended-release formulas may provide more consistent medicine and reduce fluctuations in symptoms. This is because the formula slowly releases the drug into the body. This provides a consistent level of medicine throughout the day.1,5

People with PD may see a movement disorder specialist. The specialist should be trained in treating PD and understand the role of PD drugs, including which drugs may worsen symptoms.

Before beginning treatment for Parkinson's disease, 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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