Flu Treatment Options: Xofluza vs Tamiflu

• Tamiflu and Xofluza are prescription antiviral drugs that treat and prevent the flu when started within 48 hours of symptoms.
• Tamiflu is taken twice daily for 5 days, approved for infants 2 weeks and older, and works by preventing the flu virus from spreading between infected cells.
• Xofluza is a single-dose oral treatment for ages 5 and up, working by stopping the virus from multiplying.
• Both reduce flu duration by about 1–2 days; Xofluza offers dosing convenience and may help with resistant strains, while Tamiflu is available generically at lower cost and approved for younger children.

Every year, millions of Americans battle the flu, a highly contagious respiratory illness caused by influenza A or B viruses. While most people recover with rest and fluids, antiviral medications can shorten symptoms, reduce severity, and prevent complications, especially in high-risk groups.

Two leading options are Xofluza and Tamiflu. Both are FDA-approved and recommended by the CDC, but they differ in how they work, how you take them, and who they’re best for.

Understanding the Flu and How Antivirals Work

Once the virus enters your body, it attaches to healthy cells in your airways and begins to use those cells to make copies of itself. Each new copy goes on to infect more cells. This rapid spread triggers inflammation, causing symptoms like sudden fever, chills, muscle aches, fatigue, cough, and sore throat.

Antiviral drugs don’t cure the flu, but they interfere with the virus’s life cycle, reducing replication and giving your immune system a head start. Starting antivirals within 48 hours of symptom onset can:

• Shorten illness by about 1 day
• Reduce symptom severity
• Lower risk of complications like pneumonia
• Decrease viral shedding (so you’re less contagious)

What Are Xofluza and Tamiflu?

Both Xofluza and Tamiflu are prescription antiviral medications used to treat and prevent influenza A and B. They are not antibiotics and do not work against bacterial infections or COVID-19.

For years, Tamiflu (oseltamivir phosphate) was the primary oral antiviral prescription. Then, in 2018, the FDA approved a new drug: Xofluza (baloxavir marboxil).

How Do They Work?

Though both medications fight the flu, they work in different ways by targeting different parts of the virus.

Tamiflu slows down the spread of the virus, while Xofluza stops the virus from making copies to begin with. This unique mechanism is also why Xofluza may be effective against some flu strains that have developed resistance to Tamiflu.

How Well Do They Work?

Studies show that both Xofluza and Tamiflu are effective in reducing flu symptoms when taken within 48 hours of onset. However, there are some differences:

• Symptom Duration: Both reduce symptoms by about 1 day compared to placebo.
• Viral Load Reduction: Xofluza reduces viral load faster, within 24 hours, compared to 72 hours with Tamiflu. This may help reduce transmission, especially in households.
• Household Transmission: Xofluza may be more effective in preventing flu spread among close contacts.
• Resistance: Xofluza’s unique mechanism may be effective against strains resistant to neuraminidase inhibitors like Tamiflu.

In a large pediatric trial, Xofluza showed comparable symptom relief to Tamiflu but with fewer gastrointestinal side effects and better adherence due to its single-dose format.

How to Take Them

Tamiflu

• Treatment: Twice daily for 5 days
• Prevention: Once daily for at least 10 days (up to 6 weeks during outbreaks)
• Dosing:
  Adults: 75 mg per dose
  Children: Weight-based dosing
  Infants (2 weeks to younger than 1 year): 3 mg/kg per dose

Tamiflu requires a full course to be effective, so adherence is important. It’s available in liquid form for children or those who can’t swallow capsules.

Xofluza

• Treatment: One-time oral dose within 48 hours of symptom onset
• Prevention: One-time dose as soon as possible after exposure
• Dosing:
  Children under 20 kg: 2 mg/kg
  20–80 kg: 40 mg
  Over 80 kg: 80 mg

Because it’s a single dose, Xofluza is especially helpful for people who may forget to take multiple doses or have trouble swallowing pills over several days.

Side Effects

Both medications are generally well-tolerated, but they can cause side effects.

Common Side Effects

• Tamiflu: The most commonly reported side effects are nausea and vomiting. This is why healthcare providers often recommend taking Tamiflu with a full meal.
• Xofluza: Common side effects include diarrhea, headache, and bronchitis or sinusitis (inflammation of the airways or sinuses). Some clinical studies suggest Xofluza may cause fewer overall stomach-related side effects than Tamiflu.

Serious and Rare Side Effects

It is important to watch for rare but serious side effects with any antiviral medication.

• Severe Allergic Reactions: Both drugs carry a risk of severe allergic reactions (hypersensitivity), which may present as a spreading rash, swelling of the face or throat, or difficulty breathing. If this occurs, patients should seek immediate medical attention.
• Neuropsychiatric Events (Tamiflu): There have been rare reports of temporary confusion, delirium, hallucinations, or abnormal behavior associated with Tamiflu use, primarily reported in children in Japan. Patients and parents should be monitored closely for any signs of unusual behavior during treatment.

Interactions: What to Avoid

Tamiflu

Tamiflu does not have major drug interactions with most medications. However, it can interfere with the Live Attenuated Influenza Vaccine (LAIV), commonly known as the nasal spray flu vaccine (FluMist).

• Avoid taking Tamiflu within 2 weeks before or 48 hours after receiving LAIV.
• Tell your doctor about any other medication or supplements you use.

Xofluza and Minerals

Xofluza’s effectiveness can be reduced by certain minerals and supplements, including:

• Dairy Products: Milk, yogurt, and cheese
• Calcium-Fortified Drinks: Juices, almond milk, other beverages with added calcium
• Antacids and Mineral Supplements: Products containing aluminum, calcium, iron, magnesium, selenium, or zinc

Taking Xofluza near the time of consuming these items can reduce the amount of the drug that gets into your bloodstream, making the treatment less effective. A healthcare provider will usually advise a clear time window (e.g., several hours) to separate the Xofluza dose from any of these items.

When to Choose Xofluza vs Tamiflu

• Convenience: Some may prefer a “one and done” regimen (Xofluza), others may be comfortable with a 5-day course (Tamiflu).
• Age & Medical History: Tamiflu is approved for infants as young as two weeks (treatment) and is the preferred choice for very young children. Xofluza is used for ages 5 and older.
• Drug Resistance: In cases where flu strains are resistant to oseltamivir, Xofluza provides proven efficacy.
• Household Flu Exposure: New studies suggest Xofluza may reduce secondary transmission after treating one infected person.
• Cost: Generic Tamiflu is often more affordable.

When to See Your Doctor

Still feeling sick after a few days on Xofluza or Tamiflu? Call your doctor. A fever that comes back or symptoms that start to worsen again could mean your body needs more help.

If you’re short of breath, lightheaded, or your chest feels tight, don’t wait. Go in and get checked. These medications can make the flu easier to manage, but you may still need medical care.

If you’re pregnant, or living with asthma, heart disease, diabetes, or a weak immune system, talk with your doctor before taking either one.

Keep in mind that Tamiflu and Xofluza won’t work for COVID-19. The virus that causes COVID is not the same as the flu.

Remember, if your face or throat swells, you get a rash that spreads fast, or it becomes hard to breathe, call 911 or go to the ER. Getting help right away can prevent serious problems.