Amantadine, Oral Capsule

Highlights for amantadine

1. Amantadine oral capsule is available as a brand-name drug and a generic drug.
2. Amantadine comes in the following oral forms: immediate-release capsule, extended-release capsule (available only as brand-name drug Gocovri), immediate-release tablet, extended-release tablet (available only as brand-name drug Osmolex ER), and syrup.
3. Amantadine oral capsule is used to treat Parkinson’s disease and drug-induced movement problems. It’s also approved to help prevent and treat influenza (flu) type A, though the Centers for Disease Control and Prevention (CDC) does not recommend this use.

What is amantadine?

Amantadine is a prescription drug. It comes in the following forms: immediate-release capsule, extended-release capsule, immediate-release tablet, extended-release tablet, and syrup. All forms are oral (taken by mouth). “Extended release” means the drug is slowly released into your body over a long period of time. “Immediate release” means the drug is released into your body right away.

Amantadine extended-release capsule is currently only available as the brand-name drug Gocovri. The Food and Drug Administration (FDA) has approved a generic version of this drug, but it’s unknown when it will be available to prescribe. Amantadine extended-release tablet is currently only available as the brand-name drug Osmolex ER.

Amantadine immediate-release oral capsule is available as a generic drug. Generic drugs usually cost less than the brand-name version. In some cases, they may not be available in every strength or form as the brand-name drug.

This article focuses mainly on amantadine immediate-release oral capsule. For information about the other forms of amantadine, talk with your doctor or pharmacist.

Why it’s used

Amantadine oral capsule is used to treat a variety of movement disorders caused by Parkinson’s disease. It can also be used to treat movement disorders caused by certain drugs. For these uses, the drug is typically prescribed to adults only.

In addition, this drug can be used to prevent and treat influenza type A in adults and some children. However, the Centers for Disease Control and Prevention (CDC) does not recommend the drug for this purpose. This is due to the high level of resistance the influenza type A virus has to this drug. Also, note that amantadine is not a substitute for annual flu shots.

When taken to treat Parkinson’s disease, this drug may be used as part of a combination therapy. This means you may need to take it with other medications.

Not all forms of amantadine are FDA approved for these same conditions. For example, Gocovri, the extended-release capsule, is not approved to prevent or treat influenza type A.

How it works

Amantadine belongs to a class of drugs called antivirals. A class of drugs is a group of medications that have a similar mechanism of action. (Mechanism of action refers to how a drug works.) These drugs are often used to treat similar conditions.

It’s not fully understood how amantadine works as an antiviral or anti-Parkinson’s disease drug.

Amantadine can block the multiplying of influenza type A virus in the body. In people with Parkinson’s disease and drug-induced movement disorders, amantadine increases the effect of a chemical in your brain called dopamine. This helps your body better control your movements.

Amantadine side effects

Amantadine can cause mild or serious side effects. The following list contains some of the key side effects that may occur while taking amantadine. This list does not include all possible side effects.

For more information on the possible side effects of amantadine or tips on how to manage a bothersome side effect, talk with your doctor or pharmacist.

More common side effects

Some of the more common side effects that can occur with use of amantadine include:

• nausea
• dizziness and lightheadedness
• insomnia (difficulty sleeping)

If these effects are mild, they may go away within a few days to a couple of weeks. If they’re more severe or do not go away, talk with your doctor or pharmacist.

Serious side effects

Call your doctor right away if you have serious side effects. Call 911 if your symptoms feel life threatening or if you think you’re having a medical emergency. Serious side effects and their symptoms can include the following:

• Hallucinations (seeing or hearing something that’s not really there).
• Atypical thoughts.
• Coma.
• Intense urges, such as new or increased urges to gamble, have sex, or go on impulsive shopping sprees.
• Melanoma (skin cancer) in people with Parkinson’s disease. If you take this drug to treat Parkinson’s, you should have a healthcare professional check your skin regularly.
• Heart failure. Symptoms can include:
  • fluid buildup in your legs
  • fluid buildup in your chest
  • shortness of breath
  • getting more easily out of breath
  • irregular heartbeat, faster heartbeat, or both
• Neuroleptic malignant syndrome. This is a rare but sometimes fatal reaction caused by increased dopamine in a certain part of the brain. Symptoms can include:
  • fever
  • rigid muscles
  • involuntary movements
  • altered consciousness
  • mental status changes
  • fast pulse
  • fast and shallow breathing
  • high or low blood pressure

Amantadine may interact with other medications

Amantadine can interact with several other medications. Different interactions can cause different effects. For instance, some can interfere with how well a drug works, while others can cause increased side effects.

The text that follows lists medications that can interact with amantadine. This list does not contain all drugs that may interact with amantadine.

Before taking amantadine, be sure to tell your doctor and pharmacist about all prescription, over-the-counter, and other drugs you take. Also tell them about any vitamins, herbs, and supplements you use. Sharing this information can help you avoid potential interactions.

If you have questions about drug interactions that may affect you, ask your doctor or pharmacist.

Central nervous system stimulants

If you take central nervous system stimulants with amantadine, you may experience increased nervousness, irritability, insomnia (difficulty sleeping), seizures, or arrhythmias (irregular heart rhythms). Examples of central nervous system stimulants include:

• dextroamphetamine
• atomoxetine (Strattera)
• methylphenidate (Ritalin)

Anticholinergic drugs

Taking amantadine with anticholinergic medications can increase side effects of both drugs, such as dry mouth, urinary retention (not being able to fully empty your bladder), blurred vision, and drowsiness. Examples of anticholinergic drugs include:

• diphenhydramine (Benadryl)
• scopolamine
• tolterodine (Detrol)
• benztropine

Heart drugs

Taking certain heart drugs with amantadine can increase the level of amantadine in your body. This can raise your risk of side effects such as nausea, dizziness, or insomnia. This can also raise your risk of death or other serious side effects from overdose of amantadine. Examples of these heart drugs include:

• triamterene (Dyrenium)
• hydrochlorothiazide (Maxzide)

Malaria drugs

Taking certain malaria drugs with amantadine can increase the level of amantadine in your body. This can increase your risk of side effects such as nausea, dizziness, or insomnia. This can also increase your risk of death or other serious side effects from overdose of amantadine. Examples of these malaria drugs include:

• quinine
• quinidine

Influenza vaccine

Receiving live attenuated influenza vaccine (the nasal spray form of the flu vaccine) while you’re taking amantadine can make the influenza vaccine less effective. People who take amantadine should receive this vaccine either 2 weeks before taking amantadine or 48 hours after taking it. If that isn’t possible, you should receive a different type of flu vaccine called an inactivated vaccine (flu shot).

Amantadine cost and coupons

Whether you have health insurance or not, cost may be a factor when you’re considering amantadine oral capsule. What you’ll pay for amantadine may depend on several things, such as your treatment plan and the pharmacy you use.

Here are a few things to consider regarding cost:

• Cost information and savings coupons: You can visit Optum Perks to get price estimates of what you’d pay for amantadine when using coupons from the site. See the coupon options below. (Note: Optum Perks coupons cannot be used with any insurance copays or benefits.)
• Savings programs: If you have questions about how to pay for your prescription, talk with your doctor or pharmacist. In addition, you can visit Medicine Assistance Tool and NeedyMeds, two websites offering resources that may help decrease the price you pay for amantadine.

You can also check out a few tips for how to save money on prescriptions.

How to take amantadine

The amantadine dosage your doctor prescribes will depend on several factors. These include:

• the type and severity of the condition you’re using amantadine to treat
• your age
• the form of amantadine you take
• other medical conditions you may have

Typically, your doctor will start you on a low dosage and adjust it over time to reach the dosage that’s right for you. They’ll ultimately prescribe the smallest dosage that provides the desired effect.

The following information describes dosages that are commonly used or recommended. However, be sure to take the dosage your doctor prescribes for you. Your doctor will determine the best dosage to suit your needs.

Dosage for Parkinson’s disease

Generic: amantadine

• Form: immediate-release oral capsule
• Strength: 100 milligrams (mg)

Brand: Gocovri

• Form: extended-release oral capsule
• Strength: 68.5 mg, 137 mg

“Immediate release” means the drug is released into your body right away. “Extended release” means the drug is slowly released into your body over a long period of time.

Amantadine immediate-release capsule

Adult dosage (ages 18 to 64 years)

• Typical starting dosage: 100 mg taken twice per day, when not used with other drugs for Parkinson’s disease.
• In some cases: Some people may need to start with 100 mg, taken once per day, if they have certain serious medical illnesses or are taking high doses of other drugs to treat Parkinson’s disease.
• Maximum dosage: 200 mg, taken twice per day.

Child dosage (ages 0 to 17 years)

It has not been confirmed that amantadine is safe and effective for use in people younger than 18 years of age.

Older adult dosage (ages 65 years and older)

The kidneys of older adults may not work as well as they used to. This can cause the body to process drugs more slowly. As a result, a higher amount of a drug stays in the body for a longer time. This increases the risk of side effects. If you’re an older adult, your doctor will likely start you on a lower dosage of amantadine than usual.

Gocovri (amantadine) extended-release capsule

Adult dosage (ages 18 to 64 years)

• Typical starting dosage: 137 mg, taken once per day at bedtime.
• Dosage increases: After 1 week, your doctor will likely increase the dosage to 274 mg (two 137-mg capsules) once per day at bedtime.

Child dosage (ages 0 to 17 years)

It has not been confirmed that Gocovri is safe and effective for use in people younger than 18 years of age.

Older adult dosage (ages 65 years and older)

The kidneys of older adults may not work as well as they used to. This can cause the body to process drugs more slowly. As a result, a higher amount of a drug stays in the body for a longer time. This increases your risk of side effects, such as falls and hallucinations (seeing or hearing something that’s not really there).

The manufacturer of Gocovri does not recommend dosage adjustments based on age. If you’re an older adult, your doctor will likely check your kidney function before and during treatment. They’ll reduce your dosage if needed based on this monitoring.

Dosage for drug-induced movement problems

Generic: amantadine

• Form: immediate-release oral capsule
• Strength: 100 mg

Adult dosage (ages 18 to 64 years)

• Typical dosage: 100 mg, taken twice per day. However, some people may need to take 300 mg per day in divided doses.

Child dosage (ages 0 to 17 years)

It has not been confirmed that amantadine is safe and effective for use in people younger than 18 years of age.

Senior dosage (ages 65 years and older)

The kidneys of older adults may not work as well as they used to. This can cause your body to process drugs more slowly. As a result, an increased amount of a drug stays in your body for a longer time. This raises your risk of side effects. If you’re an older adult, your doctor may start you on a lower dosage of amantadine than usual.

Dosage for prevention and treatment of influenza type A

Generic: amantadine

• Form: immediate-release oral capsule
• Strength: 100 mg

Adult dosage (ages 18 to 64 years)

• Typical dosage: 200 mg taken once per day, or 100 mg taken twice per day.

Child dosage (ages 9 to 12 years)

• Typical dosage: 200 mg taken once per day, or 100 mg taken twice per day.

Child dosage (ages 1 to 8 years)

Dosage is based on weight, which a healthcare professional will calculate. It should not exceed 150 mg per day.

Child dosage (ages 0 to 11 months)

It has not been confirmed that amantadine is safe and effective for use in people younger than 1 year of age.

Older adult dosage (ages 65 years and older)

• Typical dosage: 100 mg per day.

Special dosage considerations

For people with kidney disease: Your dosage will depend on the severity of your kidney disease. You may take 200 mg of amantadine on the first day, then 100 mg per day thereafter. However, you may take 200 mg on the first day, then 100 mg every other day. If you have very severe kidney disease or are on dialysis, you should not take any more than 200 mg once per week.

Dosage warnings

Death from overdose has been reported in a person who ingested 1 g (1,000 mg) of amantadine. There is no antidote for this type of overdose, so it’s extremely important to take amantadine exactly as your doctor prescribed it.

Amantadine warnings

This drug comes with several warnings.

Suicide

Some people who took amantadine have attempted suicide, even some without mental health conditions. Also, amantadine can worsen mental health problems in people who have mental health conditions or substance use disorder.

When people attempt suicide, they usually demonstrate atypical behaviors beforehand. These may include:

• confusion
• depression
• personality changes
• agitation
• aggressive behavior
• hallucinations (seeing or hearing something that’s not really there)
• paranoia
• excessive sleepiness
• insomnia (difficulty sleeping)

If you experience any of these effects during amantadine treatment, contact your doctor right away.

Driving or operating heavy machinery

If you have blurry vision, confusion, or disorientation after taking amantadine, you should not drive, operate heavy machinery, or work in a situation in which you need to be alert or able to move well.

Stopping the drug too quickly

If you’re taking amantadine for Parkinson’s disease, do not abruptly stop taking it. If you do, you may experience serious side effects, including agitation, hallucinations, slurred speech, and depression.

Allergic reaction

Amantadine can cause a severe allergic reaction. Symptoms can include:

• difficulty breathing and swallowing
• swelling of the face, such as around the eyes and the mouth
• fever
• hives
• rash

If you develop these symptoms, call 911 or go to the nearest emergency room.

Do not take this drug again if you’ve ever had an allergic reaction to it. Taking it again could be fatal.

Alcohol interaction

Drinking alcohol can increase your risk of side effects from this drug. These side effects can include dizziness, confusion, lightheadedness, and positional low blood pressure (low blood pressure when you stand). If you drink alcohol, talk with your doctor. They can let you know how much alcohol, if any, is safe to consume while taking amantadine.

Warnings for people with certain health conditions

For people with epilepsy or seizures: Taking amantadine can increase the severity and number of seizures you have.

For people with kidney disease: Deaths have been reported in people with kidney disease who took more than the recommended dosage of amantadine. This can happen with doses as low as 1 g and can cause heart failure, respiratory failure, kidney failure, and central nervous system failure.

For people with heart disease: People with a history of heart failure or peripheral edema (swelling of the legs or arms) are at increased risk of heart failure when they take amantadine.

For people with glaucoma: People with certain types of glaucoma should not use amantadine because it can cause the pupils to dilate. This can increase eye pressure.

For people with recurring eczema-type rash: Taking amantadine can increase the severity of the rash or the number of rashes you get.

For people with mental health conditions: Taking amantadine can make your condition become more severe. You may also have increased suicidal thoughts or behaviors.

Warnings for other groups

For pregnant people: There haven’t been enough studies done during pregnancy to know how the drug might affect a fetus.

Talk with your doctor if you’re pregnant or planning to become pregnant. This drug should be used only if the potential benefit justifies the potential risk to your pregnancy.

If you become pregnant while taking this drug, contact your doctor right away.

For people who are breastfeeding: Amantadine passes into breast milk and may cause side effects in a child who is breastfed. Talk with your doctor if you breastfeed your child. You may need to decide whether to stop breastfeeding or stop taking this drug.

When to call the doctor

You should call your doctor if your Parkinson’s disease gets worse, if your movement disorder gets worse, or if your flu symptoms become more severe.

If any of these things occur, your doctor may need to change your dosage or prescribe a different medication.

Take as directed

Amantadine is used for short-term treatment of influenza. It’s used for long-term treatment of Parkinson’s disease and drug-induced movement problems. This drug comes with risks if you do not take it as prescribed.

If you stop taking the drug or do not take it at all: If you stop taking the drug suddenly, this might cause certain effects, such as agitation, hallucinations, anxiety, or slurred speech. If you do not take the drug at all, your condition will not get better.

If you miss doses or do not take the drug on schedule: Your medication may not work as well or may stop working completely. For this drug to work well, a certain amount needs to be in your body at all times.

What to do if you miss a dose: Take your dose as soon as you remember. But if you remember just a few hours before your next scheduled dose, take only one dose. Never try to catch up by taking two doses at once. This could result in dangerous side effects.

If you take too much: You could have dangerous levels of the drug in your body, or you could die. Symptoms of overdose include:

• difficulty breathing
• fast or irregular heart rhythm
• high blood pressure
• confusion
• hallucinations
• fluid buildup in your legs

If you think you’ve taken too much amantadine, call your doctor right away. You can also call America’s Poison Centers at 800-222-1222 or use its online tool. However, if your symptoms are severe, call 911 or go to the nearest emergency room.

How to tell if the drug is working: If you’re taking amantadine for Parkinson’s disease, you should have fewer tremors. You should also feel less rigid and be able to move more smoothly.

If you’re taking this drug for drug-induced movement problems, you should be able to move more smoothly and control your movements better.

If you’re taking this drug for influenza type A, you should have fewer flu symptoms or a flu that doesn’t last very long.

Important considerations for taking amantadine

Keep these considerations in mind if your doctor prescribes amantadine for you.

General

• You can take amantadine with or without food.
• You should not open the capsule.

Storage

• Store amantadine at room temperature between 68°F and 77°F (20°C and 25°C). It can be temporarily stored in temperatures from 59°F to 86°F (15°C to 30°C).
• You should not store this medication in moist or damp areas, such as bathrooms.

Refills

A prescription for this medication is refillable. You should not need a new prescription for this medication to be refilled. Your doctor will write the number of refills authorized on your prescription.

Travel

When traveling with your medication:

• Always carry your medication with you. When flying, never put it into a checked bag. Keep it in your carry-on bag.
• You do not need to worry about airport X-ray machines. They can’t harm your medication.
• You may need to show airport staff the pharmacy label for your medication. Always carry the original prescription-labeled container with you.
• You should not put this medication in your car’s glove compartment or leave it in the car. Be sure to avoid doing this when the weather is very hot or very cold.

Clinical monitoring

Your doctor will likely check your kidney function during amantadine treatment.

If you take this drug for Parkinson’s disease, you will need to see a dermatologist periodically. This is to check your skin for possible melanoma (skin cancer).

Availability

Not every pharmacy stocks this drug. When filling your prescription, be sure to call ahead to make sure your pharmacy carries it.

Prior authorization

Many insurance companies require a prior authorization for this drug. This means your doctor will need to get approval from your insurance company before your insurance company will pay for the prescription.