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amantadine

Pronunciation

Generic Name: amantadine (a MAN ta deen)
Brand Name: Symmetrel

What is 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 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.

Before taking amantadine, tell your doctor if you have epilepsy or other seizure disorder, congestive heart failure, kidney or liver disease, low blood pressure, eczema, glaucoma, or a history of mental illness, suicide attempt, or drug/alcohol addiction.

Slideshow: Top 11 Reasons Why You Should Get Your Flu Vaccine Now

Amantadine can cause side effects that may impair your thinking, vision, 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.

You may have increased sexual urges, unusual urges to gamble, or other intense urges while taking this medication. Talk with your doctor if you believe you have any intense or unusual urges while taking amantadine.

What should I discuss with my healthcare provider before taking amantadine?

You should 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.

If you have any of these other conditions, you may need a dose adjustment or special tests to safely take amantadine:

  • epilepsy or other seizure disorder;

  • congestive heart failure;

  • kidney disease;

  • liver disease;

  • low blood pressure or fainting;

  • eczema;

  • glaucoma; or

  • a history of mental illness, suicide attempt, or drug/alcohol addiction.

You may have increased sexual urges, unusual urges to gamble, or other intense urges while taking amantadine. It is not known whether the medicine actually causes this effect. Talk with your doctor if you believe you have any intense or unusual urges while taking amantadine.

Some people taking medicines for Parkinson's disease have developed skin cancer (melanoma). However, people with Parkinson's disease may have a higher risk than most people for developing melanoma. Talk to your doctor about your specific risk and what skin symptoms to watch for. You may need to have regular skin exams.

FDA pregnancy category C. It is not known whether this medication is harmful to an unborn baby. Before taking amantadine, 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 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, start taking the medication within 24 to 48 hours after flu symptoms begin. Keep taking 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 fever, anxiety, severe headache, confusion, hallucinations, agitation, aggression, personality changes, tremor, problems with balance or walking, fast or uneven heart rate, urinating less than usual or not at all, trouble breathing, seizure (convulsion), or fainting.

What should I avoid while taking 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 vision, thinking, or reactions. Be careful if you drive or do anything that requires you to be alert and able to see clearly.

Avoid getting up too fast from a sitting or lying position, or you may feel dizzy. Get up slowly and steady yourself to prevent a fall.

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.

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, hallucinations, thoughts of hurting yourself;

  • urinating less than usual or not at all;

  • high fever, stiff muscles, confusion, sweating, fast or uneven heartbeats, rapid breathing, feeling like you might pass out;

  • 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), strange dreams;

  • feeling nervous;

  • nausea, diarrhea, 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. Call your doctor for medical advice about side effects. You may report side effects to FDA at 1-800-FDA-1088.

See also: Side effects (in more detail)

Amantadine dosing information

Usual Adult Dose for Influenza Prophylaxis:

Normally recommended dose: 200 mg orally per day in 1 to 2 divided doses

Comments:
-Twice-daily dosing may minimize central nervous system (CNS) side effects.
-In healthy adults not at risk for influenza-related complications, 100 mg per day may be effective for prophylaxis; not known if 100 mg/day is as effective as 200 mg/day.
-For patients with intolerance to 200 mg/day due to CNS or other toxicities, 100 mg/day is recommended.

Approved indications: For treatment of uncomplicated respiratory tract illness due to influenza A virus strains, especially when used early in course of illness; for chemoprophylaxis against signs/symptoms of influenza A virus infection

Usual Adult Dose for Influenza A:

Normally recommended dose: 200 mg orally per day in 1 to 2 divided doses

Comments:
-Twice-daily dosing may minimize central nervous system (CNS) side effects.
-In healthy adults not at risk for influenza-related complications, 100 mg per day may be effective for prophylaxis; not known if 100 mg/day is as effective as 200 mg/day.
-For patients with intolerance to 200 mg/day due to CNS or other toxicities, 100 mg/day is recommended.

Approved indications: For treatment of uncomplicated respiratory tract illness due to influenza A virus strains, especially when used early in course of illness; for chemoprophylaxis against signs/symptoms of influenza A virus infection

Usual Adult Dose for Parkinson's Disease:

Monotherapy:
100 mg orally twice a day; onset usually within 48 hours

In patients with serious associated medical illnesses or receiving high doses of other antiparkinson drugs:
Initial dose: 100 mg once a day
After 1 to several weeks at initial dose: The dose may be increased to 100 mg orally twice a day, if needed.

Comments:
-Patients whose responses are not optimal at 200 mg/day may benefit from an increase up to 400 mg per day in divided doses; close supervision recommended.
-Amantadine's efficacy can wane after a few months. If patient is not at maximum tolerated dose, increasing dose may help. Alternatively, temporary discontinuation of drug for several weeks may help to recover some of the drug's effects when it is reinstated. The use of other antiparkinson drugs may be necessary.

Concomitant therapy:
-When amantadine and levodopa are started concurrently, rapid therapeutic benefits may occur. Amantadine dose should remain constant at 100 mg orally once or twice a day while the daily dose of levodopa is gradually increased to optimal benefit.
-Additional benefit may result from adding amantadine to optimal well-tolerated doses of levodopa; such benefit includes smoothing out improvement fluctuations that can occur with levodopa alone. Patients who reduce levodopa dose due to side effects may regain lost benefit with the addition of amantadine.

Approved indication: For treatment of parkinsonism

Usual Adult Dose for Extrapyramidal Reaction:

100 mg orally twice a day

Comments:
-Patients whose responses are not optimal at 200 mg/day may benefit from an increase up to 300 mg per day in divided doses.

Approved indication: For treatment of drug-induced extrapyramidal reactions

Usual Geriatric Dose for Influenza Prophylaxis:

Normally recommended dose:
65 years or older: 100 mg orally per day

Approved indications: For treatment of uncomplicated respiratory tract illness due to influenza A virus strains, especially when used early in course of illness; for chemoprophylaxis against signs/symptoms of influenza A virus infection

Usual Geriatric Dose for Influenza A:

Normally recommended dose:
65 years or older: 100 mg orally per day

Approved indications: For treatment of uncomplicated respiratory tract illness due to influenza A virus strains, especially when used early in course of illness; for chemoprophylaxis against signs/symptoms of influenza A virus infection

Usual Pediatric Dose for Influenza Prophylaxis:

Normally recommended doses:
1 to 9 years: 4.4 to 8.8 mg/kg orally per day; not to exceed 150 mg/day
10 to 12 years: 100 mg orally twice a day

Advisory Committee on Immunization Practices (ACIP) and American Academy of Pediatrics (AAP) recommendations (to reduce risk for toxicity):
1 to 9 years: 5 mg/kg orally per day in 2 divided doses; not to exceed 150 mg/day
10 years or older, less than 40 kg: 5 mg/kg orally per day
10 years or older, 40 kg or more: 100 mg orally twice a day

Alternative prophylactic dose for children weighing more than 20 kg: 100 mg per day

Approved indications: For treatment of uncomplicated respiratory tract illness due to influenza A virus strains, especially when used early in course of illness; for chemoprophylaxis against signs/symptoms of influenza A virus infection

Usual Pediatric Dose for Influenza A:

Normally recommended doses:
1 to 9 years: 4.4 to 8.8 mg/kg orally per day; not to exceed 150 mg/day
10 to 12 years: 100 mg orally twice a day

Advisory Committee on Immunization Practices (ACIP) and American Academy of Pediatrics (AAP) recommendations (to reduce risk for toxicity):
1 to 9 years: 5 mg/kg orally per day in 2 divided doses; not to exceed 150 mg/day
10 years or older, less than 40 kg: 5 mg/kg orally per day
10 years or older, 40 kg or more: 100 mg orally twice a day

Alternative prophylactic dose for children weighing more than 20 kg: 100 mg per day

Approved indications: For treatment of uncomplicated respiratory tract illness due to influenza A virus strains, especially when used early in course of illness; for chemoprophylaxis against signs/symptoms of influenza A virus infection

What other drugs will affect 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 triamterene (Dyrenium), hydrochlorothiazide (HCTZ, Dyazide, HydroDiuril, Hyzaar, Lopressor, Vasoretic, Zestoretic), and others; or

  • phenothiazines such as prochlorperazine (Compazine), thioridazine (Mellaril), and others.

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.

Where can I get more information?

  • Your pharmacist can provide more information about amantadine.
  • Remember, keep this and all other medicines out of the reach of children, never share your medicines with others, and use this medication only for the indication prescribed.
  • Disclaimer: Every effort has been made to ensure that the information provided by Cerner Multum, Inc. ('Multum') is accurate, up-to-date, and complete, but no guarantee is made to that effect. Drug information contained herein may be time sensitive. Multum information has been compiled for use by healthcare practitioners and consumers in the United States and therefore Multum does not warrant that uses outside of the United States are appropriate, unless specifically indicated otherwise. Multum's drug information does not endorse drugs, diagnose patients or recommend therapy. Multum's drug information is an informational resource designed to assist licensed healthcare practitioners in caring for their patients and/or to serve consumers viewing this service as a supplement to, and not a substitute for, the expertise, skill, knowledge and judgment of healthcare practitioners. The absence of a warning for a given drug or drug combination in no way should be construed to indicate that the drug or drug combination is safe, effective or appropriate for any given patient. Multum does not assume any responsibility for any aspect of healthcare administered with the aid of information Multum provides. The information contained herein is not intended to cover all possible uses, directions, precautions, warnings, drug interactions, allergic reactions, or adverse effects. If you have questions about the drugs you are taking, check with your doctor, nurse or pharmacist.

Copyright 1996-2012 Cerner Multum, Inc. Version: 6.02. Revision Date: 2010-12-15, 5:01:39 PM.

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