Skip to Content


Generic Name: baloxavir marboxil (ba LOX a vir mar BOX il)
Brand Name: Xofluza

Medically reviewed by Philip Thornton, DipPharm. Last updated on Dec 19, 2018.

What is Xofluza?

Xofluza (baloxavir marboxil) is used to treat flu symptoms caused by influenza virus in people who have had symptoms for no more than 48 hours. It will not treat the common cold.

Xofluza is for adults and children who are at least 12 years old and weigh at least 88 pounds (40 kilograms).

Xofluza should not be used in place of getting a yearly flu shot. The Centers for Disease Control and Prevention recommends an annual flu shot to help protect you each year from new strains of influenza virus.

Important Information

Xofluza may contain inactive ingredients, which can cause allergic reactions or other problems.

Follow all directions on your medicine label and package. Tell each of your healthcare providers about all your medical conditions, allergies, and all medicines you use.

Before taking this medicine

You should not use Xofluza if you are allergic to baloxavir marboxil.

Tell your doctor if you are pregnant or breast-feeding.

It is not known whether this medicine will harm an unborn baby. However, having influenza during pregnancy can cause severe complications that could harm both mother and baby. The benefit of using Xofluza to treat flu symptoms may outweigh any risks.

The Centers for Disease Control and Prevention recommends that pregnant women get a flu shot during any trimester of pregnancy to protect themselves and their newborn babies from flu.

How should I take Xofluza?

Take Xofluza exactly as prescribed by your doctor. Follow all directions on your prescription label and read all medication guides or instruction sheets.

Xofluza is usually given as a single dose of 1 or more tablets to be taken at one time.

Take Xofluza when you first notice flu symptoms (fever, chills, muscle aches, sore throat, runny or stuffy nose). This medicine may not be effective if you have been sick for longer than 48 hours.

You may take Xofluza with or without food.

Do not take this medicine with dairy products such as milk or yogurt, or with calcium-fortified juice.

Also avoid taking this medicine with a laxative, antacid, or vitamin/mineral supplement that contains calcium, magnesium, iron, selenium, or zinc.

Call your doctor if your symptoms do not improve, or if they get worse.

Store tablets in the blister pack at room temperature, away from moisture and heat.

Xofluza dosing information

Usual Adult Dose for Influenza:

40 to less than 80 kg: 40 mg orally once as a single dose
At least 80 kg: 80 mg orally once as a single dose

Use: For the treatment of acute uncomplicated influenza in patients symptomatic for no more than 48 hours

Usual Pediatric Dose for Influenza:

12 years or older:
-Weight 40 to less than 80 kg: 40 mg orally once as a single dose
-Weight at least 80 kg: 80 mg orally once as a single dose

Use: For the treatment of acute uncomplicated influenza in patients symptomatic for no more than 48 hours

What happens if I miss a dose?

Xofluza is used as a single dose and does not have a daily dosing schedule.

What happens if I overdose?

Seek emergency medical attention or call the Poison Help line at 1-800-222-1222.

What should I avoid after taking Xofluza?

Ask your doctor before getting a "live" flu vaccine (such as nasal FluMist). Baloxavir marboxil may interfere with the drug action of FluMist, making the vaccine less effective.

Xofluza side effects

Get emergency medical help if you have signs of an allergic reaction to Xofluza: hives; difficult breathing; swelling of your face, lips, tongue, or throat.

Common Xofluza side effects may include:

This is not a complete list of side effects and others may occur. Call your doctor for medical advice about side effects. You may report side effects to FDA at 1-800-FDA-1088.

What other drugs will affect Xofluza?

Other drugs may interact with baloxavir marboxil, including prescription and over-the-counter medicines, vitamins, and herbal products. Tell your doctor about all your current medicines and any medicine you start or stop using.

Further information

Remember, keep this and all other medicines out of the reach of children, never share your medicines with others, and use Xofluza only for the indication prescribed.

Always consult your healthcare provider to ensure the information displayed on this page applies to your personal circumstances.

Frequently Asked Questions