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Baloxavir marboxil

Generic name: baloxavir marboxil [ ba-LOX-a-vir-mar-BOX-il ]
Brand name: Xofluza
Dosage form: oral tablet (20 mg; 40 mg; 80 mg)
Drug class: Miscellaneous antivirals

Medically reviewed by on Sep 21, 2021. Written by Cerner Multum.

What is baloxavir marboxil?

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

Baloxavir marboxil is also used to prevent flu symptoms in people who have been in contact with someone who has the flu.

Baloxavir marboxil is for adults and children at least 12 years old and weighing at least 88 pounds (40 kilograms).

Baloxavir marboxil 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.

Baloxavir marboxil may also be used for purposes not listed in this medication guide.


Use only as directed. Tell your doctor if you use other medicines or have other medical conditions or allergies.

Before taking this medicine

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

Tell your doctor if you are pregnant or plan to become pregnant. Having influenza during pregnancy can cause severe complications that could harm both mother and baby. The benefit of treating influenza may outweigh any risks to the baby.

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.

Tell your doctor if you are breastfeeding.

How should I take baloxavir marboxil?

Follow all directions on your prescription label and read all medication guides or instruction sheets. Use the medicine exactly as directed.

Baloxavir marboxil is usually given as a single dose to be taken at one time. baloxavir marboxil will be provided either as tablets or a liquid (oral suspension) that is mixed by a healthcare professional.

Baloxavir marboxil doses are based on weight. Follow all dosing instructions carefully, and do not share this medicine with another person.

Take baloxavir marboxil 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.

If you are taking baloxavir marboxil to prevent flu symptoms, take your dose as soon as possible after you've been in contact with someone who has the flu.

You may take baloxavir marboxil 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 baloxavir marboxil with a laxative, antacid, or vitamin/mineral supplement that contains aluminum, 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. You must use the liquid within 10 hours after it was mixed.

What happens if I miss a dose?

Baloxavir marboxil 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 baloxavir marboxil?

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.

Baloxavir marboxil side effects

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

Common side effects of baloxavir marboxil 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 baloxavir marboxil?

Other drugs may affect baloxavir marboxil, including prescription and over-the-counter medicines, vitamins, and herbal products. Tell your doctor about all other medicines you use.

Frequently asked questions

Further information

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

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