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Side Effects
Serious

Skin rash, confusion, seizures, hallucinations, swollen feet or arms, difficulty breathing. Call your doctor at once.
Common

Dizziness, irritability, distractibility, difficulty sleeping. Consult your doctor if such symptoms persist.
Less Common

Mild skin rash, weakness, depression, fatigue, anxiety, headache, lightheadedness, loss of appetite, nausea, constipation, dry mouth. Consult your doctor if such symptoms persist.
Amantadine Hydrochloride


Drug Class:
Antiviral/antiparkinsonism agent

Available OTC?: No

Available Generic?: Yes

Generic 100 mg
(Invamed)
Available In
Why Prescribed
How It Works
Range and Frequency
Onset of Effect
Duration of Action
Dietary Advice
Storage
Missed Dose
Stopping the Drug
Prolonged Use
Over 60
Driving and Hazardous Work
Alcohol
Pregnancy
Breast Feeding
Infants and Children
Special Concerns
Overdose Symptoms
What to Do
Drug Interactions
Food Interactions
Disease Interactions


Available In
Tablets, syrup

Why Prescribed
To prevent or treat type A influenza; to treat Parkinson's disease. It may also be used to minimize stiffness and shaking caused by certain other drugs prescribed for treating nervous, mental, or emotional disorders.

How It Works
The exact mechanism of action is unknown, though amantadine appears to prevent the influenza A virus from penetrating and entering healthy cells. In Parkinsonism, it increases the release and activity of dopamine, which plays a key role in the control of muscle movement. The increased availability of dopamine in the brain helps compensate for the reduction in the natural supply caused by the disease, and so eases symptoms of Parkinsonism.

Range and Frequency
For treatment or prevention of influenza-- Adults: 100 to 200 mg a day in one or two doses for five days. Children: Up to 150 mg once a day. For Parkinsonism-- Adults: 100 mg, two times a day. In some cases the maximum dose may be increased to 400 mg a day. Older patients and those with a history of seizure disorders are usually given reduced doses, generally 100 mg a day.

Onset of Effect
For influenza A: two hours. For Parkinsonism: 48 hours.

Duration of Action
Up to 12 hours.

Dietary Advice
Take it with or after meals.

Storage
Store in a tightly sealed container away from heat and direct light.

Missed Dose
If you miss a dose, take it as soon as you remember unless it is almost time for your next dose. In that case, skip the missed dose and return to your regular schedule. Do not double the next dose.

Stopping the Drug
Influenza: For prevention, take amantadine for the full treatment period as recommended by your doctor; for treatment, do not stop taking amantadine without consulting your doctor. Parkinsonism: Doses must be decreased gradually according to your doctor's instructions.

Prolonged Use
Prolonged use requires periodic checks by your doctor.

Over 60
Older persons are generally more sensitive to amantadine and more likely to experience adverse side effects. Smaller doses may be warranted.

Driving and Hazardous Work
Amantadine can cause drowsiness, dizziness, blurred vision, or confusion. Avoid driving and hazardous work until you determine how the medicine affects you.

Alcohol
Avoid alcohol since it may increase side effects such as dizziness and blurred vision.

Pregnancy
In some animal studies, amantadine has been shown to cause birth defects, though human studies have not been done. Accordingly, the drug should be avoided during the first three months of pregnancy. Notify your doctor if you are pregnant or plan to become pregnant.

Breast Feeding
Amantadine passes into breast milk and should not be taken while breast feeding.

Infants and Children
Safety for children under the age of one has not been established.

Special Concerns
Individuals with kidney disease must take reduced dosages and be closely monitored.

Overdose Symptoms
Hyperactivity, disorientation, confusion, visual hallucinations, seizures, drop in blood pressure, palpitations or heart rhythm disturbances.

What to Do
Call your doctor, emergency medical services (EMS), or the nearest poison control center immediately.

Drug Interactions
The effects of amantadine can be altered by amphetamines, diet pills, asthma and cold medicines, methylphenidate, nabilone, and pemoline. Anticholinergic drugs can increase the side effects of amantadine.

Food Interactions
None are expected.

Disease Interactions
Caution is advised when taking this medication. Consult your doctor if you have eczema, epilepsy, heart disease, circulation problems, kidney disease, or an emotional disorder.

Date Published: 04/13/2005
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