Amantadine is a pharmaceutical agent also known as 1-adamantylamine or 1-aminoadamantane. This drug 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 relieves tiredness and fatigue found in multiple sclerosis patients. Although amantadine is generally 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 influenza viruses. It acted as an antiviral agent because it inhibited the ability of viral particles to effectively enter host cells. As of early 2011, the US Centers for Disease Control and Prevention (CDC) has declared that this drug is not effective against current influenza strains. They recommended using alternative medications such as oseltamivir and zanamivir. Because the predominant strains of influenza may change from year to year, it is possible that amantadine may once again be useful in treating influenza infections.
Parkinson's disease, which is a progressive neurological condition that causes problems with the body's motor and sensory systems, has also been treated with amantadine. This condition develops in part because levels of a neurotransmitter called dopamine decrease in the brain. The drug helps control symptoms by prolonging the time that dopamine remains active in the brain; The drug's ability to perform this function was accidentally discovered by observing patients taking the drug for influenza infection. Although recent research has suggested that the drug 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 US Federal Drug Administration (FDA) does not indicate that this drug is useful in this application, but many doctors use it for this purpose. Another unapproved use of the drug is to treat attention deficit hyperactivity disorder (ADHD) in children.
Amantadine is available by prescription only in the US. It is usually given as a pill or as a liquid, and is usually taken once or twice a day. The medicine has the brand name Symmetrel®.
Common side effects of amantadine are nausea, dizziness, depression, irritability, constipation, hallucinations, confusion, and anxiety. More serious side effects can include problems with heart function, allergic reactions, and decreases in the counts of various blood cells. Patients with heart problems, glaucoma, kidney failure, and abnormal liver function should exercise caution while taking this medication as they may experience more serious side effects.