4 Common and Serious Side Effects of Xofluza

Alan Lucks | MD

Medically reviewed by Alan Lucks | MD, Alan Lucks MDPC Private Practice - New York on December 2nd, 2025.

Key Takeaways

  • Xofluza is an antiviral medication used to treat the flu quickly.

  • Like all medicines, it can cause side effects, some mild and some more serious.

  • Knowing the common side effects helps you stay safe and comfortable during treatment.

  • Serious side effects need immediate medical attention.

  • For personalized advice and telehealth visits about Xofluza side effects, visit Doctronic.ai.

Understanding Xofluza Side Effects

Xofluza, known generically as Baloxavir Marboxil, is particularly noteworthy for its single-dose treatment regimen, which sets it apart from other antiviral medications that often require multiple doses over several days. This convenience can be a game-changer for patients seeking quick relief from flu symptoms. The medication works by inhibiting the cap-dependent endonuclease activity of the viral polymerase, effectively blocking the replication of the influenza virus in the body. This mechanism not only helps in reducing the duration of the flu but also minimizes the severity of symptoms, allowing individuals to return to their daily activities more swiftly.

While many patients tolerate Xofluza well, it is important to be aware of potential side effects, which can include nausea, diarrhea, and headache. These side effects are generally mild and transient, but it's crucial to monitor any changes in your health during treatment. More serious side effects, although rare, can occur and may include allergic reactions or severe skin reactions. Being informed about these possibilities can empower patients to seek timely medical advice if they experience unusual symptoms, ensuring a safer treatment journey. Always consult with a healthcare professional before starting any new medication, especially if you have pre-existing health conditions or are taking other medications.

1. Nausea and Upset Stomach

Nausea is one of the most common side effects experienced by people taking Xofluza. It happens because the medication can irritate the stomach lining. You might feel queasy or even vomit shortly after taking the pill. This side effect usually appears soon after the first dose and can last a few hours to a couple of days.

To reduce nausea, try taking Xofluza with a light snack or a full glass of water. Avoid greasy or heavy meals while your stomach feels sensitive. If nausea becomes severe or lasts longer than a few days, it’s a good idea to check in with a healthcare provider.

In addition to nausea, some individuals may also experience a general feeling of discomfort in their stomach, which can be accompanied by bloating or gas. This discomfort can be particularly distressing, especially if you are already feeling unwell due to the flu. Staying hydrated is crucial; sipping on clear fluids like ginger ale or herbal teas can help soothe your stomach. Ginger, in particular, is known for its anti-nausea properties and can be a gentle remedy to alleviate symptoms.

Another helpful tip is to engage in light, calming activities that can distract you from the discomfort. Gentle walks or practicing deep breathing exercises can help ease the queasiness. However, if you find that your symptoms are persistent or worsening, it’s essential to consult with a healthcare professional who can provide guidance tailored to your specific situation. They may recommend alternative treatments or medications that can help manage these side effects more effectively.

2. Diarrhea

Diarrhea is another common side effect of Xofluza. The medicine can affect your gut bacteria and digestion, leading to loose or watery stools. This usually starts within a day or two of treatment and can last for several days.

Staying hydrated is key when experiencing diarrhea. Drink plenty of water or electrolyte drinks to replace lost fluids. If diarrhea is severe, causes dehydration, or lasts more than a week, contact your doctor for advice.

3. Headache

Many people report headaches after taking Xofluza. This side effect can range from mild to moderate and may feel like a tension headache or pressure around the head. Headaches often start within the first day of treatment and usually go away on their own.

Over-the-counter pain relievers like Acetaminophen or ibuprofen can help ease headaches. Make sure to follow the dosing instructions. If headaches are very painful, persistent, or accompanied by other symptoms such as vision changes, seek medical help promptly.

4. Serious Side Effects: Liver Problems

Though uncommon, Xofluza may cause liver problems in some people. Symptoms to watch for include yellowing of the skin or eyes (jaundice), dark urine, severe stomach pain, or persistent nausea and vomiting. These signs suggest liver inflammation or damage.

If you experience any of these symptoms, stop taking the medication and contact your healthcare provider immediately. Early detection and treatment can prevent more serious complications.

A sick man lying in bed, blowing his nose, surrounded by tissues, medicine, and a glass of water on a bedside table.How to Manage and Reduce Side Effects of Xofluza

Take Medicine With Food

Taking Xofluza with a small meal or snack can help reduce nausea and stomach upset. Avoid taking it on an empty stomach if you notice these side effects.

Stay Hydrated

Drinking plenty of fluids helps manage diarrhea and prevent dehydration. Water, herbal teas, and electrolyte drinks are good choices.

Rest and Monitor Symptoms

Resting while your body fights the flu and the medication works is important. Keep track of any side effects and how long they last. If symptoms worsen or new ones appear, seek medical advice.

Xofluza Allergic Reactions and Warnings

While rare, allergic reactions to Xofluza can happen and require immediate attention. Signs include rash, itching, swelling of the face or throat, severe dizziness, or trouble breathing. These symptoms indicate a serious allergic reaction called anaphylaxis.

If you notice any of these symptoms after taking Xofluza, call emergency services or go to the nearest emergency room right away. It’s important to tell your healthcare provider if you have a history of allergies to antiviral medications before starting Xofluza.

When to Contact Your Doctor About Xofluza Side Effects

Most side effects of Xofluza are mild and go away on their own. However, you should contact your doctor if you experience:

  • Severe or persistent nausea, vomiting, or diarrhea

  • Signs of an allergic reaction, such as rash, swelling, or difficulty breathing

  • Yellowing of the skin or eyes, or other liver-related symptoms

  • Severe headaches or dizziness

For quick and convenient access to healthcare advice, consider using Doctronic.ai. Their AI-powered doctor can provide personalized guidance on side effects and help you decide if you need a telehealth visit with a real doctor.

Learn More About Xofluza Side Effects With Doctronic

Doctronic.ai offers a unique way to understand your medication side effects. Their AI doctor uses the latest medical research to give you clear, personalized information that fits your health history. Whether you want to know how to reduce side effects or when to seek care, Doctronic is ready 24/7 to help you.

If you have questions about Xofluza or any other medication, Doctronic’s free AI visits can provide quick answers. For more detailed care, you can schedule affordable video visits with licensed doctors across all 50 states.

The Bottom Line About Xofluza Side Effects

Xofluza is a powerful antiviral that helps fight the flu quickly, but like all medicines, it can cause side effects. Most are mild and manageable with simple steps like taking the medicine with food and staying hydrated. Serious side effects and allergic reactions are rare but need immediate care.

For personalized advice and easy access to medical support, Doctronic.ai is a valuable resource. It combines AI and real doctors to give you the best care experience from your home.

Frequently Asked Questions

Tell your doctor about any allergies before starting Xofluza. If you have had allergic reactions to similar antiviral drugs, your doctor may recommend a different treatment.

Most side effects, such as nausea, headache, and diarrhea, last a few days after starting treatment. If they persist longer, contact your healthcare provider.

Always check with your doctor or pharmacist before combining medications. Xofluza may interact with certain drugs, so professional advice is important.

Take the missed dose as soon as you remember. If it’s almost time for your next dose, skip the missed one. Do not double up doses.

Xofluza is approved for use in people 12 years and older. For younger children, other flu treatments may be recommended.

References

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