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amantadine

Pronunciation

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

What is amantadine?

Amantadine is an antiviral medicine that blocks the actions of viruses in your body.

Amantadine is used to treat and prevent influenza A (a viral infection). Amantadine may not be effective during every flu season because certain strains of influenza virus may be resistant to this medicine.

Amantadine should not be used in place of getting a yearly flu shot. The Centers for Disease Control recommends an annual flu shot to help protect you each year from new strains of influenza virus.

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 purposes not listed in this medication guide.

What is the most important information I should know about amantadine?

Do not take more than your recommended dose. An amantadine overdose can be fatal.

Do not receive a "live" nasal flu vaccine (FluMist) while taking amantadine, and for at least 48 hours after your last dose. You should not take amantadine if you have received a nasal flu vaccine within the past 14 days.

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

You should not use amantadine if you are allergic to it, or:

  • if you have received a nasal flu vaccine (FluMist) within the past 14 days.

To make sure amantadine is safe for you, tell your doctor if you have:

  • epilepsy or other seizure disorder;

  • congestive heart failure;

  • kidney disease;

  • liver disease;

  • low blood pressure or a history of fainting;

  • eczema;

  • glaucoma;

  • a history of alcoholism or drug addiction; or

  • a history of mental illness, psychosis, or suicidal thoughts or actions.

Older adults may be more sensitive to the effects of this medicine.

You may have increased sexual urges, unusual urges to gamble, or other intense urges while taking this medicine. Talk with your doctor if this occurs.

People with Parkinson's disease may have a higher risk of skin cancer (melanoma). Talk to your doctor about this risk and what skin symptoms to watch for.

It is not known whether this medicine will harm an unborn baby. Tell your doctor if you are pregnant or plan to become pregnant.

Amantadine can pass into breast milk and may harm a nursing baby. You should not breast-feed while using this medicine.

Amantadine should not be given to a child younger than 1 year old.

How should I take amantadine?

Follow all directions on your prescription label. Do not take this medicine in larger or smaller amounts or for longer than recommended.

Measure liquid medicine with the dosing syringe provided, or with a special dose-measuring spoon or medicine cup. If you do not have a dose-measuring device, ask your pharmacist for one.

If you take amantadine to treat influenza A, start taking the medicine within 24 to 48 hours after flu symptoms begin. Keep taking amantadine for the full prescribed length of time. Your symptoms may improve before the infection is completely cleared.

If you take this medicine for Parkinson symptoms, your doctor may occasionally change your dose to make sure you get the best results.

Amantadine will not treat an infection caused by bacteria. Call your doctor if your symptoms do not improve, or if you have a fever with a headache, cough, skin rash, or other new symptoms.

If you take amantadine for Parkinson symptoms: You should not stop using amantadine suddenly or your condition may become worse.

Store at room temperature away from moisture, heat, and light. Keep the bottle tightly closed when not in use.

What happens if I miss a dose?

Take the missed dose as soon as you remember. Skip the missed dose if it is almost time for your next scheduled dose. Do not take extra medicine to make up the missed dose.

What happens if I overdose?

Seek emergency medical attention or call the Poison Help line at 1-800-222-1222. An overdose of amantadine can be fatal.

Overdose symptoms may include fever, aggression, behavior changes, hallucinations, severe headache or pounding in your ears, muscle stiffness, problems with balance or walking, fast heart rate, urinating less than usual, trouble breathing, seizure (convulsion), or fainting.

What should I avoid while taking amantadine?

Do not receive a "live" nasal flu vaccine (FluMist) while using amantadine, and for at least 48 hours after you stop taking amantadine. The vaccine may not work as well during this time, and may not fully protect you from disease.

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.

Drinking alcohol with this medicine can cause side effects.

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 signs of an allergic reaction: hives; difficult breathing; swelling of your face, lips, tongue, or throat.

Call your doctor at once if you have:

  • shortness of breath (even with mild exertion), swelling in your hands or feet;

  • painful or difficult urination;

  • depression, agitation, or aggression;

  • behavior changes, hallucinations, thoughts of hurting yourself;

  • a seizure (convulsions); or

  • severe nervous system reaction--very stiff (rigid) muscles, high fever, sweating, confusion, fast or uneven heartbeats, tremors, feeling like you might pass out.

Common side effects may include:

  • dizziness;

  • nausea; or

  • sleep problems (insomnia).

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?

Other drugs may interact with amantadine, including prescription and over-the-counter medicines, vitamins, and herbal products. Tell each of your health care providers about all medicines you use now and any medicine you start or stop using.

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: 7.01. Revision Date: 2015-11-25, 12:34:47 PM.

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