Osmolex ER, Gocovri

Introduction

Written by Sarah Lewis, PharmD
Medically reviewed by Melissa Badowski, PharmD, MPH, FCCP
Updated on October 9, 2023

Amantadine (a MAN ta deen) is a generic medication prescribed for Parkinson’s disease. It’s also prescribed for movement problems caused by certain drugs and for treating and preventing influenza A infection. Amantadine belongs to a group of drugs called adamantanes.

Common questions about amantadine

Below you’ll find answers to a few commonly asked questions about amantadine.

Can amantadine be used in dogs?

Possibly. Veterinarians (vets) sometimes use amantadine in dogs and other small animals to manage pain. But it isn’t approved for this use.

Talk with your vet to learn more about using amantadine in dogs. Do not administer amantadine or any other medications to a pet without talking with your vet.

What brand names are available for amantadine?

Currently, there aren’t any brand-name drugs available for amantadine oral tablet, oral capsule, or oral solution. These forms of amantadine are generic versions of the brand-name drug Symmetrel. But this drug is no longer on the market.

A generic medication is an identical copy of the active drug in a brand-name medication. (An active drug is the ingredient that makes a medication work.) Generic drugs are believed to be as effective and safe as brand-name drugs. And generic drugs typically cost less compared to brand-name drugs.

There are brand-name versions of amantadine extended-release oral tablet (Osmolex ER) and extended-release capsule (Gocovri). But these forms aren’t covered in this article. To find out more about these forms, talk with your doctor or pharmacist.

How does amantadine work? And how long does it take to start working? 

Amantadine’s mechanism of action (how it works) isn’t fully understood. In Parkinson’s disease and drug-induced movement problems, it likely works by increasing the levels of the brain chemical dopamine. For treating and preventing influenza A infection, it stops the virus from reproducing itself.

Amantadine should start working within 2 days of starting it. For Parkinson’s disease, it may take longer to see the full effect.

If you’d like to know more about this, talk with your doctor or pharmacist.

Side effects of amantadine

Amantadine may cause mild or serious side effects. More common mild side effects of amantadine and its serious side effects are listed below. This article doesn’t include all possible side effects of the drug. Side effects can vary based on your age, overall health, and any other medications you take.

To learn more about amantadine’s side effects, ask your doctor or pharmacist. You can also refer to the prescribing information for amantadine listed in the “Resources” section.

Mild side effects

More common mild side effects reported with some forms of amantadine are listed below.

This article doesn’t include all possible mild side effects of the drug. To learn more about amantadine’s side effects, refer to the prescribing information for amantadine listed in the “Resources” section.

With many drugs, mild side effects may go away within a few days or a couple of weeks. If the side effects are bothersome, tell your doctor or pharmacist. They may be able to suggest ways to manage them.

Amantadine oral tablet, oral solution, and oral capsule’s mild side effects include:

• constipation
• dizziness
• nausea
• sleep problems
• mild allergic reaction*

* For details about this side effect, see the “Interactions and warnings for amantadine” section.

Serious side effects

Serious side effects of amantadine are listed below.

This article doesn’t include all possible serious side effects of the drug. To learn more about amantadine’s side effects, refer to the prescribing information for amantadine listed in the “Resources” section.

With many drugs, serious side effects are possible but not common. If you have serious side effects from this drug, call your doctor right away. If you’re having severe symptoms or a medical emergency, call 911 or a local emergency number.

In general, amantadine’s serious side effects include:

• blurred vision that can affect driving and other activities
• depression or other mood changes
• hallucinations (seeing or hearing things that aren’t really there)
• heart failure
• impulsive behaviors or intense urges
• low white blood cell counts
• neuroleptic malignant syndrome (a rare reaction to certain drugs that can be life threatening)
• reduced mental alertness, which can affect driving and other activities
• shortness of breath
• sudden drop in blood pressure upon standing or sitting up, which can lead to fainting or falls
• suicidal thoughts or attempts
• swelling in the feet, legs, or hands due to fluid retention
• trouble urinating
• unusual thoughts or beliefs
• severe allergic reaction*

* For details about this side effect, see the “Interactions and warnings for amantadine” section.

Suicide prevention

If you or someone you know is in crisis and considering suicide or self-harm, please seek support:

• Call the 988 Suicide and Crisis Lifeline at 988.
• Text HOME to the Crisis Textline at 741741.
• Not in the United States? Find a helpline in your country with Befrienders Worldwide.
• Call 911 or your local emergency services number if you feel safe to do so.

If you’re calling on behalf of someone else, stay with them until help arrives. You may remove weapons or substances that can cause harm if you can do so safely.

If you are not in the same household, stay on the phone with them until help arrives.

Uses of amantadine

The Food and Drug Administration (FDA) approves prescription drugs such as amantadine for certain conditions. Approved uses for amantadine are described below.

Use for influenza A

Doctors may prescribe amantadine oral tablet, oral capsule, or oral solution for treating or helping prevent influenza A infection. It’s used for this purpose in adults and children 1 year and older. It’s usually prescribed as a short-term treatment.

With influenza A infection, you develop symptoms of the viral respiratory illness commonly known as the flu. Symptoms can include:

• body aches
• cough
• fatigue (low energy)
• fever or chills
• headache
• runny or stuffy nose
• sore throat

Symptoms usually start suddenly and can last 7–10 days. Taking amantadine can help shorten this time and may make symptoms milder.

Amantadine only works against influenza A viruses. This is the most common type of influenza virus. It won’t work if you have an influenza B infection.

Use for Parkinson’s disease

Doctors may prescribe amantadine oral tablet, oral capsule, or oral solution for treating Parkinson’s disease. It’s used for this purpose in adults. It’s usually prescribed as a long-term treatment.

With Parkinson’s disease, low levels of the brain chemical dopamine cause problems with movement and muscle control. Symptoms may include:

• balance or coordination problems
• changes in posture
• mood changes
• reduced ability to blink, smile, or have other facial expressions
• slow movements
• stiff muscles
• tremor
• trouble speaking, chewing, or swallowing

Taking amantadine may help relieve some of these symptoms.

Use for extrapyramidal symptoms

Doctors may prescribe amantadine oral tablet, oral capsule, or oral solution for treating extrapyramidal symptoms (ES). It’s used for this purpose in adults who take certain medications. It can be prescribed as a long-term or short-term treatment.

With ES, you develop movement problems as side effects of certain medications. Antipsychotic drugs are the most common cause of ES. Other drugs that can cause ES include antidepressants, lithium, stimulants, and certain anti-nausea drugs.

ES can include:

• changes in muscle tone
• restlessness
• slow movements similar to Parkinson’s disease symptoms
• uncontrollable movements in the face or other body part

ES can lead to serious and life threatening complications in some cases.

Interactions and warnings for amantadine

Below you’ll find information about amantadine’s possible interactions and warnings.

Interactions of amantadine

Certain things may affect how a drug works. These include getting vaccines, consuming alcohol or certain foods, or taking the drug with other medications. This effect is called a drug interaction.

Before you take amantadine, ask your doctor to check for possible interactions. Be sure to tell them about any of the following you take or use:

• prescription or over-the-counter drugs
• vitamins, herbs, or supplements

To learn about drug-condition interactions, see the “Warnings for amantadine” section below.

Warnings for amantadine

Some people should not take amantadine, and others should take it cautiously.

Amantadine could cause harm to people with certain health conditions. This effect is called a drug-condition interaction. Other factors can also affect whether amantadine is a safe option for you.

Ask your doctor about specific warnings for amantadine, and be sure to tell your doctor about your:

• current health, including any allergies to medications
• past health conditions or surgeries

Allergic reaction

Amantadine can cause an allergic reaction in some people. Severe allergic reactions are rare but possible.

If you’ve had an allergic reaction to amantadine or any of its ingredients, your doctor will likely not prescribe amantadine. They can tell you about medications that are safer options for you.

A mild allergic reaction may cause the following symptoms:

• skin rash
• itchiness
• flushing (temporary warmth, redness, or deepening of skin color)

A severe allergic reaction may cause the following symptoms:

• swelling under your skin, usually in your hands, feet, eyelids, or lips
• swelling of your mouth, throat, or tongue, which can cause breathing problems

If you have an allergic reaction to amantadine, call your doctor right away. If you have severe symptoms, call 911 or a local emergency number.

Overdose of amantadine

You should not take more amantadine than your doctor prescribes. Death has been reported in people who took too much amantadine.

If you think you’ve taken too much amantadine, call your doctor or pharmacist right away. Or you could call 800-222-1222 to speak with someone at America’s Poison Centers. You can also use its online resource. If you have concerning symptoms, call 911 or a local emergency number immediately. You can also go to the closest emergency room.

Pregnancy or breastfeeding and amantadine

Information about amantadine and pregnancy and breastfeeding is described below.

Amantadine and pregnancy

It’s not known whether amantadine should be taken during pregnancy. If you’re planning a pregnancy or can become pregnant, talk with your doctor before taking this medication.

Amantadine and breastfeeding

Amantadine should not be taken while breastfeeding. If you’re currently breastfeeding or planning to do so, talk with your doctor before taking this medication. Your doctor may recommend other ways to feed your child during treatment with amantadine.

What to ask your doctor

Let your doctor know if you have questions about amantadine or would like more details about it.

Here’s a list of some possible questions you may want to ask your doctor:

• How does amantadine compare with other drugs that could treat my condition?
• What is the most important information I need to know about amantadine?
• Do any of my other medications interact with amantadine?

Resources

• Amantadine hydrochloride capsules, USP. (2023). https://nctr-crs.fda.gov/fdalabel/services/spl/set-ids/20dad861-6ad1-4660-b315-8af57b294175/spl-doc
• Amantadine hydrochloride solution. (2022). https://nctr-crs.fda.gov/fdalabel/services/spl/set-ids/52aa093c-82cc-4d81-b072-86a2b8adc9c5/spl-doc
• Amantadine hydrochloride tablets. (2023). https://nctr-crs.fda.gov/fdalabel/services/spl/set-ids/9a99bb98-82a4-4b9e-9216-554dade72a3c/spl-doc
• Food and Drug Administration. (2023). Orange Book: Approved drug products with therapeutic equivalence evaluations. https://www.accessdata.fda.gov/scripts/cder/ob/index.cfm

Disclaimer: Optum Perks has made every effort to make certain that all information is factually correct, comprehensive, and up to date. However, this article should not be used as a substitute for the knowledge and expertise of a licensed healthcare professional. You should always consult your doctor or another healthcare professional before taking any medication. The drug information contained herein is subject to change and is not intended to cover all possible uses, directions, precautions, warnings, drug interactions, allergic reactions, or adverse effects. The absence of warnings or other information for a given drug does not indicate that the drug or drug combination is safe, effective, or appropriate for all patients or all specific uses.