Flumadine (Rimantadine) – Oral

Warning:

The Food and Drug Administration (FDA) hasn't assigned any black box warnings to Flumadine (rimantadine).

What Is Flumadine?

Flumadine (rimantadine) is a prescription medication. The FDA approved Flumadine to prevent and treat type A influenza (flu). Since the flu virus is likely resistant to Flumadine, however, the Centers for Disease Control and Prevention (CDC) doesn't recommend Flumadine as a flu preventive or treatment option.

Flumadine is an adamantane antiviral medication. It's thought to work by blocking the flu virus from uncoating itself. This is an early step for the virus to start making more copies of itself.

Flumadine is available in a tablet dosage form.

Drug Facts

Generic Name: Rimantadine

Brand Name(s): Flumadine

Drug Availability: Prescription

Therapeutic Classification: Adamantane antiviral

Available Generically: Yes

Controlled Substance: N/A

Administration Route: Oral (by mouth)

Active Ingredient: Rimantadine

Dosage Form(s): Tablet, syrup

What Is Flumadine Used For?

Flumadine is used to prevent or treat the flu. Since the flu virus is likely resistant to rimantadine, however, the CDC doesn't recommend it.

The flu affects up to 20% of the U.S. population yearly. The CDC estimates between 2019 and 2020, the flu virus was responsible for 35 million illnesses, 380,000 hospital visits, and 20,000 deaths.

If you have the flu, you may experience some of the following common symptoms:

  • Cough
  • Body aches
  • Chills
  • Fever
  • Tiredness or weakness

How to Take Flumadine

The following are general directions on using Flumadine to prevent the flu.

  • People 10 years and older typically take Flumadine by mouth twice daily for 11 days to six weeks.
  • Adults over 65 may take Flumadine by mouth once daily for 11 days to six weeks. This dosage also applies to people with severe kidney or liver impairment.
  • Children between 1 and 9 years old will take Flumadine orally once daily for five to six weeks.
  • If your child prefers an oral (by mouth) liquid suspension, ask your pharmacist to use the Flumadine tablets to compound (make) this liquid mixture.

For flu treatment with Flumadine, refer to the following typical instructions:

  • You should start Flumadine treatment within 48 hours (two days) of noticing your symptoms.
  • People 17 years and older generally take Flumadine by mouth twice daily for seven days.
  • Older adults may take Flumadine by mouth once daily for seven days.
  • People with severe kidney or liver problems may take Flumadine orally once daily for seven days.

If you're experiencing an upset stomach with Flumadine, consider taking it with food or milk.

Storage

When you receive Flumadine from the pharmacy, store it at room temperature (between 68 to 77 degrees Fahrenheit). The compounded liquid suspension version of Flumadine is only good for 14 days.

To be safe, place Flumadine in a locked cabinet or closet to keep your medication out of the reach of children and pets.

If you plan to travel with Flumadine, become familiar with your final destination's regulations. Checking information from the U.S. embassy or consulate might be helpful. In general, however, make sure to copy your Flumadine prescription. If possible, keep your medication in its original container from your pharmacy with your name on the label. If you have any questions about traveling with your medicine, ask your pharmacist or healthcare provider.

You can also ask your pharmacist or healthcare provider about the best ways to dispose of your medications. The FDA's website is a helpful resource for knowing where and how to discard all unused and expired drugs. You can also find disposal boxes in your area.

Off-Label Uses

Flumadine doesn't have any off-label uses.

How Long Does Flumadine Take to Work?

Flumadine might effectively prevent the flu for only up to six weeks.


As for treating the flu, Flumadine may help people experience one less day of flu symptoms—like fever.


Many people typically experience flu symptoms for three to seven days. Cough, tiredness, low energy, or feeling unwell may also last for more than two weeks—especially in older adults or people with chronic (long-term) lung conditions like chronic obstructive pulmonary disease (COPD).


People taking Flumadine will likely experience flu symptoms for at least two to six days. Even with Flumadine, some people may still experience flu symptoms for more than a week.

What Are the Side Effects of Flumadine ?

This is not a complete list of side effects and others may occur. A healthcare provider can advise you on side effects. If you experience other effects, contact your pharmacist or a healthcare provider. You may report side effects to the FDA at fda.gov/medwatch or 800-FDA-1088.

Common Side Effects

Some common side effects of Flumadine may include:

  • Dizziness or light-headedness
  • Nervousness
  • Sleeping troubles
  • Tiredness or low energy
  • Concentration difficulties
  • Upset stomach

Severe Side Effects

Get medical help right away if you develop the following serious side effects:

  • Confusion
  • Mood changes
  • Skin rash—like from a severe allergic reaction
  • Vision changes
  • Yellowing of the skin or eyes from liver damage

Call 911 if your symptoms feel life-threatening.

Long-Term Side Effects

Flumadine might be taken for up to six weeks, which isn't typically considered long-term use.

In a small study, however, long-term care residents did take Flumadine for a longer period of up to eight weeks to prevent the flu. During the study, the residents experienced the following side effects:

  • Anxiety or nervousness
  • Appetite loss
  • Concentration difficulties and confusion
  • Dizziness or light-headedness
  • Drowsiness, tiredness, or low energy
  • Dry mouth
  • Headaches
  • Mood changes
  • Nausea, vomiting, or stomach pain
  • Rash
  • Seizures
  • Severe allergic reaction
  • Sleeping problems
  • Weakness

Report Side Effects

Flumadine may cause other side effects. Call your healthcare provider if you have any unusual problems while taking this medication.

If you experience a serious side effect, you or your provider may send a report to the FDA's MedWatch Adverse Event Reporting Program or by phone (800-332-1088).

Dosage: How Much Flumadine Should I Take?

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The dose of this medicine will be different for different patients. Follow your doctor's orders or the directions on the label. The following information includes only the average doses of this medicine. If your dose is different, do not change it unless your doctor tells you to do so.

The amount of medicine that you take depends on the strength of the medicine. Also, the number of doses you take each day, the time allowed between doses, and the length of time you take the medicine depend on the medical problem for which you are using the medicine.

  • For oral dosage forms (suspension or tablets):
    • For treatment of flu:
      • Adults and teenagers 17 years of age and older—100 milligrams (mg) two times a day for 7 days.
      • Older adults—100 mg once a day.
      • Children up to 16 years of age—Use is not recommended.
    • For prevention of flu:
      • Adults and teenagers 17 years of age and older—100 milligrams (mg) two times a day.
      • Older adults—100 mg once a day.
      • Children 10 to 16 years of age—100 mg two times a day.
      • Children 1 to 9 years of age—Dose is based on body weight and must be determined by your doctor. The dose is 5 milligrams (mg) per kilogram (kg) of body weight once a day. Children in this age group should not receive more than 150 mg per day.
      • Children younger than 1 year of age—Use and dose must be determined by your doctor.

Modifications

The following modifications (changes) should be kept in mind when using Flumadine:

Severe allergic reaction: Avoid using Flumadine if you have a known allergy to it or its ingredients. Ask your pharmacist or healthcare provider for a complete list of the ingredients if you're unsure.

Pregnancy: In animal studies, Flumadine negatively affected the fetus. Not enough is known about the safety and effectiveness of Flumadine in pregnant people and fetuses.

Discuss with your healthcare provider if you are pregnant or plan to become pregnant. Your healthcare provider will help you weigh the benefits and risks of taking Flumadine during pregnancy.

Breastfeeding: In animal studies, Flumadine was present in breast milk. The medication was also linked to negative effects on nursing subjects. Not enough is known about the effects or safety of Flumadine in human breast milk and on nursing babies. Therefore, Flumadine's manufacturer doesn't recommend taking Flumadine while nursing.

Talk with your healthcare provider if you plan to breastfeed. Your healthcare provider will help you weigh the benefits and harms of taking Flumadine while nursing. They can also discuss the different ways available to feed your baby.

Adults over 65 years: If you're an older adult, your healthcare provider may lower your dosage to 100 milligrams once daily.

Children: The FDA approved once-daily Flumadine to prevent the flu in children between the ages of 1 and 9. However, if the child is at least 10 years old, the typical dosage is 100 milligrams twice daily—unless the child has kidney or liver problems.

To treat the flu, however, Flumadine isn't FDA approved as a treatment option in people younger than 17 years old.

Kidney problems: Individuals with kidney problems may not be able to clear medication from their bodies as easily as people with healthy kidneys. This means the medicine stays in the body longer and can have increased side effects. For this reason, your healthcare provider will likely lower your Flumadine dosage to 100 milligrams daily if you have severe kidney impairment.

Liver problems: Your healthcare provider will likely recommend a lower Flumadine dosage of 100 milligrams daily if you have severe liver impairment.

Missed Dose

If you accidentally forgot your Flumadine dose, take it as soon as you remember. If it's already close to your next scheduled dose, then skip the missed dose and take the following dose at your next scheduled dosing time. Don't try to double up to make up for the missed dose.

Try to find ways that work for you to help yourself remember to keep your appointments and take your medication routinely. If you miss too many doses, Flumadine might be less effective at treating or preventing the flu for you.

Overdose: What Happens If I Take Too Much Flumadine?

There is limited information available about Flumadine overdose. Rimantadine, the main ingredient in Flumadine, however, is very similar to amantadine, and amantadine overdose symptoms may include:

If you think you're experiencing an overdose or life-threatening symptoms, seek immediate medical attention.

What Happens If I Overdose on Flumadine?

If you think you or someone else may have overdosed on Flumadine, call a healthcare provider or the Poison Control Center (800-222-1222).

If someone collapses or isn't breathing after taking Flumadine, call 911 immediately.

Precautions

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It is important that your doctor check the progress of you or your child at regular visits to allow changes in your dose and to check for any unwanted effects.

This medicine may cause some people to become dizzy or confused, or to have trouble concentrating. Make sure you know how you react to this medicine before you drive, use machines, or do anything else that could be dangerous if you are dizzy or confused. If these reactions are especially bothersome, check with your doctor.

If your or your child's symptoms do not improve within a few days, or if they become worse, check with your doctor.

While you are being treated with rimantadine, do not have any immunizations (vaccinations) without your doctor's approval. Live virus vaccinations should not be given for 2 days after stopping rimantadine, and this medicine should be not be given 2 weeks after receiving live vaccines.

Do not take other medicines unless they have been discussed with your doctor. This includes prescription or nonprescription (over-the-counter [OTC]) medicines and herbal or vitamin supplements.

What Are Reasons I Shouldn’t Take Flumadine?

Before taking Flumadine, talk with your healthcare provider if any of the following applies to you:

  • Severe allergic reaction: If you have a severe allergic reaction to Flumadine or its ingredients, your healthcare provider wouldn't recommend this medication to you.
  • Pregnancy: Not enough is known about Flumadine's effects and safety on the pregnant parent and fetus. Talk with your healthcare provider to weigh the benefits and risks of taking Flumadine during pregnancy.
  • Breastfeeding: There is no information about Flumadine's effects and safety on nursing babies. Flumadine's manufacturer doesn't recommend taking the medication while nursing. Talk with your healthcare provider about the benefits and harms of taking Flumadine while nursing.
  • Children: Flumadine can be used to prevent the flu in children between one and 16 years old. However, people under 17 years should not use this medication to treat the flu.
  • Adults over 65 years: If you're an older adult, your healthcare provider might lower your Flumadine dosage.

What Other Medications Interact With Flumadine?

If you're planning to get the flu shot, consider not getting the live vaccine.

If you receive the live flu vaccination, however, there is a chance of an interaction between this vaccine and Flumadine. Therefore, wait two weeks after your flu vaccine before taking Flumadine. However, if you're already taking Flumadine, wait two days after your last dose before getting your live flu immunization.

Talk with your pharmacist or healthcare provider for more detailed information about medication interactions with Flumadine.

And be sure to talk with your healthcare provider about any other medicines you take or plan to take, including over-the-counter (OTC), nonprescription products, vitamins, herbs, or plant-based medicines.

What Medications Are Similar?

The FDA approved several medications for the flu. However, the CDC doesn't recommend all these FDA-approved antiflu medications.

The CDC doesn't recommend Flumadine. The CDC also doesn't support the use of amantadine.

Like Flumadine, amantadine is an adamantane antiviral medication. Both antivirals have similar effectiveness, especially in treating the flu. These antivirals also have similar rates of the following digestive-related side effects:

  • Constipation
  • Diarrhea
  • Heartburn
  • Nausea or vomiting

Compared to amantadine, however, rimantadine tends to have fewer side effects—like the following central nervous system (brain and spinal cord) effects:

  • Anxiety or nervousness
  • Concentration and focus problems
  • Light-headedness
  • Restlessness
  • Sleeping difficulties

Frequently Asked Questions

  • Why is Flumadine no longer recommended for the flu?

    The flu virus is likely resistant to Flumadine. Therefore, this medication is less effective at preventing or treating the flu. As a result, the CDC doesn't support using Flumadine for the flu.

  • Where is Flumadine available?

    Check with your local retail pharmacy regarding Flumadine availability. Since Flumadine isn't recommended for the flu, local pharmacies may not have the medication on their shelves. Therefore, they will likely need to order this medication for you.

  • How much does Flumadine cost?

    Flumadine is available as generic rimantadine. So, it's not typically a costly medication.

How Can I Stay Healthy While Taking Flumadine?

Having the flu may take you by surprise, and flu symptoms may last for days or weeks. Refer to the following general tips on what to do if you get the flu. There are also some suggestions to prevent the flu.

  • Consider a yearly flu vaccine.
  • Take flu-related medications as recommended by your healthcare provider.
  • Cover your sneeze or cough.
  • Regularly wash your hands with soap and water.
  • Avoid touching your eyes, nose, and mouth with your hands.
  • Clean high-touch surfaces and objects, such as doorknobs, light switches, and tables.
  • Keep your distance if you or someone else has the flu.
  • Stay home—except for medical-related visits—if you have the flu. You should stay home until 24 hours after you no longer have a fever.

Medical Disclaimer

Verywell Health's drug information is meant for educational purposes only and is not intended to replace medical advice, diagnosis, or treatment from a healthcare provider. Consult your healthcare provider before taking any new medication(s). IBM Watson Micromedex provides some of the drug content, as indicated on the page.

13 Sources
Verywell Health uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read our editorial process to learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.
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By Ross Phan, PharmD, BCACP, BCGP, BCPS
Ross is a writer for Verywell with years of experience practicing pharmacy in various settings. She is also a board-certified clinical pharmacist and the founder of Off Script Consults.