Symmetrel as a Treatment for MS Fatigue

Side effects of amantadine are minimal, but should you take it?

Multiple Sclerosis. Credit: BSIP/UIG / Getty Images

Symmetrel (Amantadine) is an antiviral medication which was originally prescribed to treat Parkinson’s Disease and Asian flu. The effects were discovered by chance when people with MS who were being treated for Asian flu experienced an increase in energy and lessening of their fatigue. Although it shows benefit and is widely prescribed for MS-related fatigue, Symmetrel is not specifically approved by the FDA for this application.

How It Works

It is known that Symmetrel helps release dopamine — a neurotransmitter which is similar to adrenaline in action and affects brain processes that control movement, emotional response, and ability to experience pleasure and pain — from the basal ganglia in the brain. However, it is not entirely understood why MS patients may experience improvement in their fatigue when taking this drug.

Patients taking this drug are reported to experience a definite improvement in energy. Often their general outlook also improves, possibly because they are feeling better and able to do more.

Usual Dosage

For managing fatigue in MS, the usual dosage is 100 to 200 mg daily, taken in the earlier part of the day so that it doesn’t interfere with sleep. It comes in both pill form and as a syrup. 

Side Effects

The side effects of Symmetrel are usually minor, with the most common being jitteriness and dry mouth.

Higher doses (300 mg and above) can cause livedo reticularis, which is a skin condition which results in purple blotches on the legs. Other side effects, while rarer, are important to watch for, as they can mimic or exacerbate other MS symptoms. These include:

  • Insomnia, especially if not taken early in the day (This is important to report to your doctor if it does not improve, as sleep problems can themselves be one of the causes of MS-related fatigue.)
  • Blurred vision can be a problem for somebody that already has vision problems due to optic neuritis or the residual damage from optic neuritis.
  • Constipation
  • Dizziness
  • Urinary hesitation, which can also be a result of MS-related bladder dysfunction

Potential Interactions and Warnings

Symmetrel may interact with the following: benztropine (Cogentin), hydrochlorothiazide with triamterene (Maxzide, Dyazide), medication for depression, other medication for Parkinson's disease, medication for spasms of the stomach or intestines, stimulants, trihexyphenidyl (Artane), and vitamins.

You should tell your doctor if you have epilepsy or any other type of seizures, or have ever had heart, kidney, or liver disease, heart failure, low blood pressure, recurring skin rash, or mental illness.

Other Uses in MS

Symmetrel is also prescribed to improve tremor. At one time, it was thought that the antiviral properties of Symmetrel might reduce relapses, and physicians saw apparent clinical improvement in many of their patients. However, when rigorous studies were conducted, it was shown that Symmetrel had no effect on disease course. It is possible that what was perceived as slowing of disability was improvement of fatigue or patients who were feeling so much better not noticing (or reporting) as many symptoms.

And, a 2015 Cochrane review found that it may not help with fatigue.


Mücke M, Mochamat,Cuhls H, Peuckmann-Post V, Minton O, Stone P, Radbruch L. Pharmacological treatments for fatigue associated with palliative care. Cochrane Database Syst Rev. 2015 May 30;5:CD006788. doi: 10.1002/14651858.CD006788.pub3.

Turkington, Carol. The A to Z of Multiple Sclerosis. New York: Checkmark Books. 2005.

Plaut GS. Effectiveness of amantadine in reducing relapses in multiple sclerosis. Journal of the Royal Society of Medicine. 1987 Feb;80(2):91-3.

National Library of Medicine. National Institutes of Health. Medline Plus: Amantadine.

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