Symmetrel as Treatment for MS Fatigue

Symmetrel (amantadine hydrochloride)
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Symmetrel (amantadine hydrochloride) is an antiviral drug used to treat Parkinson’s disease but is often prescribed off-label to treat fatigue in people with multiple sclerosis (MS). It was also previously used to treat influenza but has been phased out due to widespread amantadine resistance.

The anti-fatigue effects were first discovered when people with MS were treated for Asian flu and found that their energy levels were suddenly and significantly improved. Although Symmetrel is today widely prescribed to treat MS-related fatigue, it has not yet been approved for this use by the U.S. Food and Drug Administration.

How Symmetrel Works

Symmetrel acts directly on the central nervous system and helps stimulate the production of dopamine, a neurotransmitting chemical similar to adrenaline. Dopamine affects a part of the brain known as the basal ganglia which helps regulate movement, emotional response, and the ability to experience pleasure and pain.

While Symmetrel appears to offer little actual benefit to people living with Parkinson's disease, those shortcomings have translated to mild to moderate relief in people with MS-related fatigue. The mechanism of action is still not entirely understood, but the perceived benefits are such that Symmetrel is considered by many to be the first-line choice for treating this frustrating and often debilitating condition.


One study conducted in 2014 evaluated the effectiveness of the drug based on the Modified Fatigue Impact Scale (MFIS) which measures fatigue on a scale of 0 to 84. After one month use, Symmetrel was associated with a 34 percent decrease in the severity of fatigue in people with MS.

While significant, when compared to other treatment such as aspirin or acetyl-L-carnitine (a popular dietary supplement), Symmetrel was not shown to be any more or less effective.

Dosage Recommendation

For managing fatigue associated the MS, the usual dosage is 100 to 200 mg daily, taken early in the day so that it doesn’t interfere with sleep. It comes in both an orange triangular pill formulation and as a fruit-flavored syrup.

Treatment Side Effects

The side effects of Symmetrel are typically considered minor. The most common symptoms involving jitteriness and dry mouth. Doses at or above 300 milligrams can sometimes cause livedo reticularis, a skin condition characterized by purple blotches on the legs.

Other side effects of Symmetrel, while uncommon, include:

  • Insomnia, especially if taken later in the day
  • Blurred vision, particularly in persons with MS-associated optic neuritis
  • Constipation
  • Dizziness
  • Urinary hesitation

Many of these symptoms, such as insomnia and bladder dysfunction, are commonly associated with multiple sclerosis. It is, therefore, important to monitor for any worsening or reappearance of symptoms once treatment is started to better assess whether the cause is drug-related or a possible MS relapse.

Considerations and Contraindications

Symmetrel should be used with caution in persons with a seizure disorder, heart problem, kidney dysfunction, or clinical depression as its use may exacerbate the underlying cause or trigger an adverse event.

Persons diagnosed with schizophrenia or other psychotic disorders should not be prescribed as Symmetrel can worsen the psychiatric symptoms.

Due to the lack of research, Symmetrel is not recommended during pregnancy as it is unknown whether the drug can cause the harm to the fetus. It should also be avoided during breastfeeding and in women who are planning to conceive.

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