Taking Tamiflu to Treat the Flu

Treatment is beneficial if started within 48 hours

Table of Contents
View All
Table of Contents

Tamiflu (oseltamivir phosphate) is a prescription medication used to treat influenza (flu). It has been shown to shorten the duration of the flu if taken as soon as symptoms appear.

Boxes of Tamiflu
Justin Sullivan / Getty Images

Who Can Take It

Tamiflu is approved for use in adults as well as children aged 1 year and over. It should not be used in children under 1 year or in people allergic to oseltamivir phosphate or any other ingredients in Tamiflu.

On April 27, 2009, the Centers for Disease Control and Prevention (CDC) approved the use of Tamiflu in children under 12 months as well as pregnant women with confirmed cases of influenza H1N1 ("swine flu"). These two groups are at high risk of complications from influenza, and it is believed that the benefits of treatment outweigh the risks.

Consult your healthcare provider if you have kidney disease, heart disease, respiratory disease or any other serious health condition.​

When to Take Tamiflu

You may take Tamiflu to treat the flu or, in some cases, to prevent the flu. It is most effective if started within 48 hours of the onset of your flu symptoms.

If someone in your family has the flu, your healthcare provider may prescribe Tamiflu to help keep you from getting it. It is most often used in this way for people who are at high risk for complications from the flu or if someone in your house is unable to have a flu shot.

Tamiflu is also sometimes used to protect people from influenza when there are severe outbreaks in communities.


Tamiflu is a prescription medicine so you can only get it after seeing a healthcare provider. It is not available over the counter without a prescription.

If taken to treat the flu, Tamiflu will usually be prescribed to be taken twice daily for five days. There is a liquid formulation available for young children and people that aren't able to swallow pills. The amount of liquid solution will vary based on weight.

The FDA endorses the following Tamiflu doses for adults and children:

  • Adults and children 13 years and over: 75 milligrams (mg) twice daily for five days
  • Children 12 months to under 13 years: Dose adjusted based on weight, taken twice daily for five days 

People with kidney impairment may need to reduce the dose to 75 mg once daily for five days.

If used to prevent the flu when someone in your home has it, Tamiflu is usually taken once a day for 10 days. Tamiflu may be taken for up to six weeks in the case of an outbreak of influenza in the community.

Be sure to complete the entire course of treatment even if you feel better.

Side Effects

Tamiflu may cause mild to moderate nausea and vomiting. Taking the medication with food or milk may decrease these symptoms. Less common side effects include bronchitis, difficulty sleeping, and dizziness.

If you have an allergic reaction to Tamiflu, including a severe rash, stop taking it immediately and contact your healthcare provider or seek medical attention right away.

A Word From Verywell

Tamiflu is the most popular antiviral medication prescribed in the United States to treat and prevent the flu, but it is not the only option. It can cause unpleasant side effects and may be expensive depending on your insurance coverage.

If you aren't sure if Tamiflu is right for you, discuss the pros and cons with your healthcare provider to make an informed choice.

Was this page helpful?
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. U.S. Food and Drug Administration. Tamiflu (oseltamivir phosphate) capsules. Tamiflu(oseltamivir phosphate) for oral suspension.

  2. Centers for Disease Control and Prevention. Interim guidance on antiviral recommendations for patients with novel influenza A (H1N1) virus infection and their close contacts.

  3. Mclean HQ, Belongia EA, Kieke BA, Meece JK, Fry AM. Impact of late oseltamivir treatment on influenza symptoms in the outpatient setting: results of a randomized trial. Open Forum Infect Dis. 2015;2(3):ofv100. doi:10.1093/ofid/ofv100