5 Xofluza Interactions to Avoid
Key takeaways:
Xofluza (baloxavir marboxil) is FDA approved to treat and prevent the flu in adults and children ages 5 and over. It’s taken as a single, one-time dose.
Calcium, iron, and magnesium can bind to Xofluza and make it less effective. Other minerals also have this effect. So it’s best to avoid foods and drinks, antacids, or supplements that contain these ingredients the day you take Xofluza. Dairy products, antacids, and multivitamins are common examples of things to avoid.
Xofluza can make the live flu vaccine (nasal spray) less effective if they’re taken together. But a flu shot that’s inactivated won’t interact with Xofluza. If you already have flu symptoms, it’s best to wait until you’ve recovered to get vaccinated.
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Table of contents
If you or a close contact develops the fever, chills, and muscle aches that signal a flu infection, your healthcare provider may prescribe Xofluza (baloxavir marboxil). It’s a prescription medication that can help treat and prevent influenza in adults and children ages 5 and over.
Xofluza is taken as a single, one-time dose. But certain foods, medications, and supplements can lower Xofluza levels in the body and make it less effective. Here are five Xofluza interactions to be aware of to make sure you get the most out of your dose.
1. Dairy products and calcium-rich foods
Calcium can bind to Xofluza and prevent your body from absorbing it. This can keep you from getting the full, effective dose. So it’s best to avoid high-calcium foods and drinks before and after taking Xofluza.
Most dairy products contain large amounts of calcium. This includes milk and anything made from it, such as cheese, ice cream, and yogurt. Keep in mind that plant-based dairy products often have added calcium and should be avoided, too.
Other high-calcium foods include collard greens, black-eyed peas, and bok choy. And foods like breakfast cereals, breads, and juices are often fortified with calcium they wouldn’t contain naturally. So it’s a good idea to check the nutrition labels and avoid products that contain calcium the day you take Xofluza.
Since Xofluza is a one-time dose, you can go back to your regular diet the day after taking it. If you’ve already had a calcium-rich food or drink, it’s best to wait about 4 to 5 hours before taking Xofluza to prevent this interaction.
2. Antacids
Along with calcium, magnesium and aluminum can also bind to Xofluza and make it less effective. And these are all common ingredients in over-the-counter (OTC) antacids, such as Tums (calcium carbonate) and Mylanta (aluminum hydroxide / magnesium hydroxide / simethicone).
It's best to avoid antacids the day you take Xofluza. If you have heartburn, histamine-2 antagonists (H2 blockers) such as Pepcid (famotidine) are OK to take, as they won’t bind to Xofluza. But avoid products like Pepcid Complete that also contain an antacid. Proton pump inhibitors such as Prilosec (omeprazole) are also safe options.
3. Laxatives that contain magnesium
As with antacids, laxatives that contain magnesium can bind to Xofluza and make it less effective. So it’s best to avoid this combination. These products include Milk of Magnesia, magnesium citrate, and epsom salts (magnesium sulfate).
If you need constipation relief the day you take Xofluza, consider a stool softener such as Colace (docusate sodium) or a fiber-based product such as Metamucil. These won’t interfere with Xofluza’s effectiveness.
4. Multivitamins and supplements
Multivitamins and supplements are commonly taken to support overall health and well-being. But, like antacids and calcium-rich foods and beverages, they often contain calcium and other minerals that can bind to Xofluza.
It’s best to avoid taking multivitamins and supplements that have any of the following ingredients with Xofluza:
The supplement label is the best place to check for these ingredients. If you’re not sure about a product, don’t hesitate to reach out to your healthcare provider or pharmacist.
You can go back to your normal vitamin and supplement regimen the day after you take Xofluza. If you’ve already taken a product that contains one of these ingredients, it’s best to wait 4 to 5 hours before taking your Xofluza dose.
Good to know: Some OTC products that claim to help cold symptoms, such as Zicam, contain zinc. Even though they don’t work for the flu, people often take them anyway. But the zinc in these products can bind to Xofluza, so you shouldn’t take them together.
5. Live flu vaccine
The live flu vaccine comes as a nasal spray. It works by introducing a weakened form of the flu virus into your body. In response, your immune system makes antibodies that will help you fight off a real flu infection if you’re exposed to the flu virus in the future.
But if you take Xofluza at the same time as the live flu vaccine, it may kill the weakened virus in the vaccine before your body has a chance to respond to it. That will make the vaccine less effective.
If you’ve been exposed to the flu and haven’t been vaccinated, it’s fine to receive the flu vaccine. Just choose one of the flu shot options if you’re taking Xofluza the day of your vaccination. None of the available flu shots are live vaccines. If you prefer the nasal spray vaccine, wait until the day after you take Xofluza to receive it.
You shouldn’t receive any vaccines if you’re sick with the flu. But after you recover, it’s still a good idea to get your flu vaccine if you haven’t already done so. That’s because there is more than one type of flu virus spreading every year during flu season. Getting the flu vaccine will protect you from flu viruses other than the one you were infected with.
When should I contact my healthcare provider about a Xofluza interaction?
If you aren’t sure about whether it’s OK to take a medication, supplement, or food product with Xofluza, reach out to your pharmacist or healthcare provider. They can help make sure there aren’t any interactions that could make Xofluza less effective for you.
Keep in mind that since Xofluza is a one-time dose, you can go back to your normal diet and medication routine the day after taking it.
The bottom line
Xofluza (baloxavir marboxil) is an antiviral medication that’s taken as a single, one-time dose to treat or prevent the flu. Calcium, magnesium, and other minerals can bind to Xofluza and make it less effective. So it's best to avoid foods, medications, and supplements that contain them the day you take Xofluza. This includes dairy products, antacids, and multivitamins.
Xofluza can also prevent the live flu vaccine from working. But it’s best to wait until you fully recover before receiving any type of flu vaccine.
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References
Centers for Disease Control and Prevention. (2022). Live attenuated influenza vaccine [LAIV] (the nasal spray flu vaccine).
Genentech, Inc. (2023). Xofluza - baloxavir marboxil tablet, film coated, and baloxavir marboxil granule, for solution [package insert].
National Center for Complementary and Integrative Health. (n.d.). 5 tips: Natural products for the flu and colds: What does the science say?
World Health Organization. (n.d.). Food fortification.
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