What Is Amantadine?

Amantadine is a pharmaceutical agent also known as 1-adamantylamine or 1-aminoadamantane. This medication was initially developed as an antiviral agent, and was used to treat people infected with the influenza virus. Over the years, it has also been used to treat symptoms of motor dysfunction associated with Parkinson’s disease. Additionally, some people claim that it alleviates the tiredness and fatigue found in patients with multiple sclerosis. Although amantadine is typically well tolerated by patients, side effects can include dizziness, nausea, dry mouth, and constipation.

For many years, amantadine was used to treat patients infected with subtype A of the influenza virus. It acted as an antiviral agent because it inhibited the ability of viral particles to effectively enter host cells. As of early 2011, the United States Centers for Disease Control and Prevention (CDC) have stated that this medication is not effective against current influenza strains. They recommended using alternative medications such as oseltamivir and zanamivir. As the predominant strains of influenza can change from year to year, it is possible that amantadine could again become useful in treating influenza infections.

Parkinson’s disease, which is a progressive neurological condition that causes problems with the motor and sensory systems of the body, has also been treated with amantadine. This condition develops in part because levels of a neurotransmitter called dopamine are decreased in the brain. The medication helps control symptoms because it prolongs the length of time that dopamine remains active in the brain; the ability of the drug to perform this function was discovered accidentally by observing patients taking the medication for influenza infection. Although recent research has suggested that the medication is not effective in treating Parkinson’s disease, it continues to be used in this capacity.

Another use of amantadine is to help decrease fatigue in patients with multiple sclerosis, which is an autoimmune disease that attacks the nervous system. The United States Federal Drug Administration (FDA) does not indicate that this medication is helpful in this application, but many doctors do use it for this purpose. Another non-approved use of the medication is to treat attention deficit hyperactivity disorder (ADHD) in children.

Amantadine is available by prescription only in the US. It is typically given as either as a pill or as a liquid, and is usually taken either once or twice a day. The medication goes by the brand name Symmetrel®.

Common side effects of amantadine are nausea, dizziness, depression, irritability, constipation, hallucinations, confusion, and anxiety. More severe side effects can include problems with the function of the heart, allergic reactions, and decreases in the counts of different blood cells. Patients with heart problems, glaucoma, impaired kidney function, and abnormal liver function should use caution in taking this medication as they could experience more severe side effects.