What is Symmetrel (amantadine)?
Amantadine is an antiviral medication. It blocks the actions of viruses in your body.
Amantadine is used to treat and to prevent influenza A (a viral infection). There may be some flu seasons during which amantadine is not recommended because certain flu strains may be resistant to this drug.
Amantadine is also used to treat Parkinson's disease and "Parkinson-like" symptoms such as stiffness and shaking that may be caused by the use of certain drugs.
Amantadine may also be used for other purposes not listed in this medication guide.
What is the most important information I should know about Symmetrel (amantadine)?
Before taking amantadine, tell your doctor if you have epilepsy or other seizure disorder, congestive heart failure, kidney disease, liver disease, glaucoma, or a history of mental illness or suicide attempt.
Do not use FluMist nasal influenza "live vaccine" while you are being treated with amantadine and for at least 48 hours after you stop taking amantadine. The nasal vaccine may not be as effective if you receive it while you are taking amantadine. Before taking amantadine, tell your doctor if you have received a nasal flu vaccine within the past 14 days. Amantadine can cause side effects that may impair your thinking or reactions. Be careful if you drive or do anything that requires you to be alert and able to see clearly. If you are taking amantadine to treat influenza A, take the medication for the entire length of time prescribed by your doctor. Your symptoms may get better before the infection is completely treated. If you are taking amantadine to treat Parkinson symptoms, do not stop taking the medication without first talking to your doctor. If you stop taking amantadine suddenly, your condition may become worse.
What should I discuss with my healthcare provider before taking Symmetrel (amantadine)?
Do not use this medication if you are allergic to amantadine, or if you have received a nasal flu vaccine (FluMist) within the past 14 days.
Before taking amantadine, tell your doctor if you are allergic to any drugs, or if you have:
• epilepsy or other seizure disorder;
• congestive heart failure;
• kidney disease;
• liver disease;
• glaucoma; or
• a history of mental illness or suicide attempt.
If you have any of these conditions, you may need a dose adjustment or special tests to safely take amantadine.
FDA pregnancy category C. This medication may be harmful to an unborn baby. Tell your doctor if you are pregnant or plan to become pregnant during treatment. Amantadine can pass into breast milk and may harm a nursing baby. Do not use this medication without telling your doctor if you are breast-feeding a baby.

How should I take Symmetrel (amantadine)?
Take this medication exactly as it was prescribed for you. Do not take the medication in larger amounts, or take it for longer than recommended by your doctor. Follow the directions on your prescription label.
Take this medicine with a full glass of water.
Measure the liquid form of amantadine with a special dose-measuring spoon or cup, not a regular table spoon. If you do not have a dose-measuring device, ask your pharmacist for one.
If you are taking amantadine to treat influenza A, take the medication for the entire length of time prescribed by your doctor. Your symptoms may get better before the infection is completely treated. If you are taking amantadine to treat Parkinson symptoms, do not stop taking the medication without first talking to your doctor. If you stop taking amantadine suddenly, your condition may become worse. Store amantadine at room temperature away from moisture and heat.
What happens if I miss a dose?
Take the missed dose as soon as you remember. If it is almost time for your next dose, skip the missed dose and take the medicine at your next regularly scheduled time. Do not take extra medicine to make up the missed dose.
What happens if I overdose?
Seek emergency medical attention if you think you have used too much of this medicine. An overdose of amantadine can be fatal.
Overdose symptoms may include blurred vision, severe headache, anxiety, confusion, hallucinations, aggression, tremor, fast or uneven heart rate, trouble breathing, seizure (convulsion), or coma.
What should I avoid while taking Symmetrel (amantadine)?
Do not use FluMist nasal influenza "live vaccine" while you are being treated with amantadine and for at least 48 hours after you stop taking amantadine. The nasal vaccine may not be as effective if you receive it while you are taking amantadine. Before taking amantadine, tell your doctor if you have received a nasal flu vaccine within the past 14 days. Amantadine can cause side effects that may impair your thinking or reactions. Be careful if you drive or do anything that requires you to be alert and able to see clearly. Avoid drinking alcohol. It can increase some of the side effects of amantadine.
Avoid taking diet pills, caffeine pills, or other stimulants (such as ADHD medications) without your doctor's advice. Taking a stimulant together with amantadine can increase your risk of unpleasant side effects.

Symmetrel (amantadine) side effects
Get emergency medical help if you have any of these signs of an allergic reaction: hives; difficulty breathing; swelling of your face, lips, tongue, or throat. Call your doctor at once if you have any of these serious side effects:
• feeling short of breath, even with mild exertion;
• swelling, rapid weight gain;
• feeling depressed agitated, or aggressive;
• behavior changes, thoughts of hurting yourself;
• fever, stiff muscles, confusion, sweating, fast or uneven heartbeats;
• feeling light-headed, fainting;
• urinating less than usual or not at all;
• restless muscle movements in your eyes, tongue, jaw, or neck; or
• tremor (uncontrolled shaking).
Less serious side effects may include:
• dizziness, drowsiness, headache;
• sleep problems (insomnia);
• nausea, constipation, loss of appetite;
• dry mouth, dry nose; or
• loss of balance or coordination.
This is not a complete list of side effects and others may occur. Tell your doctor about any unusual or bothersome side effect.
What other drugs will affect Symmetrel (amantadine)?
Before taking amantadine, tell your doctor if you are using any of the following drugs:
• atropine (Atreza, Sal-Tropine, and others);
• dicyclomine (Bentyl);
• glycopyrrolate (Robinul);
• hyoscyamine (Anaspaz, Levbid, Levsin, Nulev, and others);
• mepenzolate (Cantil);
• methscopolamine (Pamine);
• propantheline (Pro-Banthine);
• scopolamine (Maldemar, Scopace, Transderm-Scop).
• quinine (Qualaquin);
• quinidine (Cardioquin, Quinaglute);
• a diuretic (water pill) such as chlorothiazide (Diuril), hydrochlorothiazide (HCTZ, HydroDiuril, Hyzaar, Lopressor, Vasoretic, Zestoretic), chlorthalidone (Hygroton, Thalitone), indapamide (Lozol), metolazone (Mykrox, Zaroxolyn), and others; or
• phenothiazines such as chlorpromazine (Thorazine), fluphenazine (Prolixin), mesoridazine (Serentil), perphenazine (Trilafon), prochlorperazine (Compazine), thioridazine (Mellaril), or trifluperazine (Stelazine).
This list is not complete and there may be other drugs that can interact with amantadine. Tell your doctor about all the prescription and over-the-counter medications you use. This includes vitamins, minerals, herbal products, and drugs prescribed by other doctors. Do not start using a new medication without telling your doctor.