Tamiflu Antiviral Medication Facts and Uses

Fight off the Flu Before or After It Starts

Tamiflu is a prescription antiviral medication that can be used to treat an influenza infection (also known as the flu) in children and adults if their symptoms have started within the last day or two. It can also be used to prevent the flu in children, teens, and adults who have been exposed to the influenza virus.

Tamiflu box and pills
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What Tamiflu Is Used for:

Tamiflu is FDA-approved to treat the flu in adults and children. It is also indicated as prophylaxis (a preventative) against the flu for adults and children over the age of 12 months.

Tamiflu Facts:

  • The trade name for Tamiflu is oseltamivir phosphate.
  • Unlike other antiviral flu medications, such as Flumadine and Symmetrel, Tamiflu is effective against both type A and B strains of flu.
  • Tamiflu is a neuraminidase inhibitor.
  • There is a generic of Tamiflu that was approved in 2016 called oseltamivir
  • Tamiflu is available as 30-milligram (mg), 45-mg, and 75-mg capsules and as an oral suspension for children who can't swallow pills.
  • Some parents warn that the oral suspension is not a very good-tasting medicine, so you might ask your pharmacist to add extra flavoring, especially if your child does not take medicine easily.
  • Tamiflu may be taken either with or without food. Food can reduce the chance of feeling or being sick.
  • Tamiflu does not treat other flu-like viral infections, such as the stomach flu, colds, or RSV (respiratory syncytial virus).

Dosage of Tamiflu:

    • For Treatment of Flu (Note: All treatment doses should be taken twice a day for five days.)
      An adult or teen (over the age of 13) should take a 75-mg capsule.
    •  The dosage for children who are one year old and older depends on weight
    • Infants between the ages of two weeks and 12 months can take three milligrams per kilogram twice daily for five days. (Note: One kilogram equals about 2.2 pounds)
    • For Prevention of Flu
      An adult or teen should take a 75-mg capsule once a day for 10 days.
    • Children over the age of 12 months depends on weight based dosing

Tamiflu Side Effects:

The most common side effects in pediatric patients taking Tamiflu for the treatment of the flu include vomiting, abdominal pain, epistaxis (nosebleeds), headache, and feeling tired (fatigue).

What You Need To Know:

When being used as a flu treatment, Tamiflu should be started as soon as possible after a person develops flu symptoms, and at least within two days. When being used as a flu preventative, it's important to start it as soon as possible after being exposed to someone with the flu, if you have not had a flu shot. Other important information:

  • Tamiflu is thought to be effective against the avian (bird) flu, leading some countries and individuals to create stockpiles of Tamiflu.
  • A flu test can help to determine if your symptoms or your child's symptoms are caused by the flu so that you can determine whether Tamiflu will even be helpful. But treatment should not be delayed while you wait for the flu test results.
  • If you're ordering Tamiflu on the Internet, buy Tamiflu only from a reputable online pharmacy.
  • Tamiflu capsules can be compounded into a suspension by pharmacists or parents can even mix the appropriate dose of a capsule into a sweetened liquid.
3 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.
  1. Hoffmann-La Roche. Tamiflu Complete Product Information Sheet. Revised March 2011.

  2. Food and Drug Administration. Tamiflu: Consumer Questions and Answers.

  3. Smith JR. Oseltamivir in human avian influenza infection. J Antimicrob Chemother. 2010;65 Suppl 2:ii25-ii33. doi:10.1093/jac/dkq013

By Vincent Iannelli, MD
 Vincent Iannelli, MD, is a board-certified pediatrician and fellow of the American Academy of Pediatrics. Dr. Iannelli has cared for children for more than 20 years.