Patient Information for Oxfluza (Baloxavir Marboxil)
Critical Clarification
Oxfluza is NOT a vaccine—it is an oral antiviral medication used to treat or prevent influenza infection. 1 The expanded question appears to confuse Oxfluza with influenza vaccines, but these are entirely different products.
What Oxfluza Is and How It Works
Oxfluza (baloxavir marboxil) is an antiviral pill that treats active influenza infection and can also prevent influenza after exposure to someone who is sick. 1 It works differently from flu vaccines by stopping the virus from multiplying once you're already infected or exposed.
When to Take Oxfluza
For Treatment
- Take Oxfluza within 48 hours of flu symptoms starting for best results. 1
- Symptoms include fever, cough, sore throat, body aches, headache, chills, and fatigue
For Prevention
- Take Oxfluza within 48 hours after close contact with someone who has confirmed influenza. 1
- This is called post-exposure prophylaxis
How to Take Oxfluza
Take Oxfluza as a single oral dose—you only need to take it once. 1
Critical Drug Interaction Warning
DO NOT take calcium, aluminum, or magnesium products (including antacids, multivitamins, or dairy products fortified with calcium) within several hours before or after taking Oxfluza, as these will completely eliminate the medication's effectiveness. 1
Common products to avoid around the time of taking Oxfluza include:
- Antacids (Tums, Rolaids, Maalox, Mylanta)
- Calcium supplements
- Multivitamins containing minerals
- Laxatives containing magnesium
- Fortified dairy products 1
Important Limitations
Oxfluza is NOT a substitute for annual flu vaccination. 2 The flu vaccine remains the primary way to prevent influenza infection, while Oxfluza only treats or prevents flu after exposure has already occurred.
You should still receive your annual influenza vaccine even if you have taken Oxfluza during flu season. 2
Who Should Get the Flu Vaccine Instead
Everyone aged 6 months and older should receive annual influenza vaccination unless contraindicated. 2, 3
Vaccination is especially important for:
- Children under 5 years old
- Adults 65 years and older
- Pregnant women
- People with chronic medical conditions (heart disease, lung disease, diabetes, immunosuppression)
- Healthcare workers 2
Common Pitfalls to Avoid
- Do not confuse Oxfluza with flu vaccines—they serve different purposes and are not interchangeable 1
- Do not take mineral supplements or antacids near the time of Oxfluza administration—this is the most common cause of treatment failure 1
- Do not delay taking Oxfluza if prescribed—it must be taken within 48 hours of symptom onset or exposure for maximum benefit 1
- Do not skip your annual flu vaccine just because Oxfluza exists—antiviral medications are not a substitute for vaccination 2