Amantadine (a-MAN-ta-deen) is an antiviral. It is used to prevent or treat certain influenza (flu) infections (type A). Amantadine also used to treat Parkinson's disease. By improving muscle control and reducing stiffness, this medicine allows more normal movements of the body as the disease symptoms are reduced.
It has also been demonstrated that this medication is sometimes effective in relieving fatigue in multiple sclerosis.
How and why Amantadine works to combat fatigue is unknown. As with many drugs, the effectiveness of Amantadine in dealing with MS fatigue was a chance discovery that came about when a number of people with MS were being treated for flu using its anti-viral properties. The anti-viral properties may confer other benefits because viral infections have been shown to be significantly correlated with relapses.
The usual dosage for the management of fatigue in MS is 100 to 200 mg daily, taken in the earlier part of the day in order to avoid sleep disturbance.
How should this medicine be used?
Amantadine comes as a capsule and liquid to take by mouth. It is usually taken once or twice a day. Follow the directions on your prescription label carefully, and ask your doctor or pharmacist to explain any part you do not understand. Take amantadine exactly as directed. Do not take more or less of it or take it more often than prescribed by your doctor. Do not stop taking amantadine without talking to your doctor.
If this medication causes insomnia (difficulty sleeping), take the last dose several hours before bedtime.
What special precautions should I follow?
Before taking amantadine,
- tell your doctor and pharmacist if you are allergic to amantadine or any other drugs.
- tell your doctor and pharmacist what prescription and non-prescription medications you are taking, especially benztropine (Cogentin), hydrochlorothiazide with triamterene (Maxzide, Dyazide), medication for depression, other medications for spasms of the stomach or intestines, stimulants, trihexyphenidyl (Artane), and vitamins.
- 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.
- tell your doctor if you are pregnant, plan to become pregnant, or are breast-feeding. If you become pregnant while taking amantadine, call your doctor immediately. Amantadine may cause harm to the fetus.
- this medicine may cause blurred vision; be careful when driving or doing things requiring alertness.
What special dietary instructions should I follow?
Amantadine may cause an upset stomach. Take amantadine with food or milk.
What should I do if I forget a dose?
Take the missed dose as soon as you remember it. However, if it is almost time for the next dose, skip the missed dose and continue your regular dosing schedule. Do not take a double dose to make up for a missed one.
What side effects can this medication cause?
Amantadine is generally well tolerated by people with MS. Amantadine may cause side effects. Tell your doctor if any of these symptoms are severe or do not go away:
- blurred vision
- nausea
- dizziness
- lightheadedness
- faintness
- trouble sleeping
- vomiting
- dryness of the mouth
- headaches
- loss of concentration
- loss of appetite
- blotchy rashes especially in the sunlight
- irritability
- nervousness
- constipation
If you experience any of the following side effects, call your doctor immediately:
- depression or anxiety
- swelling of the hands, legs, or feet
- difficulty urinating
- shortness of breath
- rash
What storage conditions are needed for this medication?
Keep this medication in the container it came in, tightly closed, and out of reach of children. Store it at room temperature and away from excess heat and moisture (not in the bathroom). Do not freeze. Throw away any medication that is outdated or no longer needed. Talk to your pharmacist about the proper disposal of your medication.
What other information should I know?
Keep all appointments with your doctor and the laboratory. Your doctor will order certain lab tests to check your response to amantadine.
Do not let anyone else take your medication. Ask your pharmacist any questions you have about refilling your prescription. If you still have symptoms of infection after you finish the amantadine, call your doctor.