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Key takeaways
Tamiflu and Xofluza are FDA-approved antiviral medications for treating and preventing the flu, with distinct mechanisms of action and dosage requirements.
Xofluza, approved in 2018, offers a single-dose treatment option, contrasting with Tamiflu’s twice-daily regimen, potentially simplifying adherence for patients.
While both medications are effective in reducing flu symptoms, clinical trials suggest Xofluza may reduce symptoms faster than Tamiflu, but concerns about viral resistance to Xofluza have been noted.
Tamiflu is available in generic form and is generally covered by insurance; however, Xofluza, being newer and brand-name only, may be more expensive despite insurance coverage.
Drug overview & main differences | Conditions treated | Efficacy | Insurance coverage and cost comparison | Side effects | Drug interactions | Warnings | FAQ
When it comes time for flu season, it’s best to be prepared when knowing what your treatment options are. Besides getting a flu shot every year, which is highly recommended, medications are available in case you come down with the flu. These drugs can help reduce the severity and duration of flu symptoms such as headache, fever, fatigue, and muscle or joint pain.
Two FDA-approved flu treatments are Tamiflu (oseltamivir) and Xofluza (baloxavir marboxil). Although both of these drugs can treat the flu, they work in different ways and have different side effects. Read on to find out how these drugs compare.
What are the main differences between Tamiflu vs. Xofluza?
Tamiflu is the brand name for oseltamivir, which was approved by the U.S. Food and Drug Administration (FDA) in 1999. It works as a neuraminidase inhibitor (NAI) that stops the release of the flu virus from infected cells. By blocking viral release, Tamiflu decreases the spread of the virus throughout the body. Tamiflu is usually given twice daily for five days when treating influenza or once daily for 10 days for flu prevention (prophylaxis).
Xofluza is the brand name for baloxavir marboxil, which was recently approved in 2018. This new drug works as a polymerase acidic (PA) endonuclease inhibitor that stops the flu virus from making copies of itself in a process known as viral replication. In this way, Xofluza works differently than other antiviral drugs like Tamiflu (oseltamivir) and Relenza (zanamivir). The drug only needs to be taken once as a single oral dose to treat or prevent the flu.
Main differences between Tamiflu vs. Xofluza |
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|---|---|---|
| Tamiflu | Xofluza | |
| Drug class | Antiviral
Neuraminidase inhibitor |
Antiviral
Polymerase acidic (PA) endonuclease inhibitor |
| Brand/generic status | Generic version available | Generic version not currently available |
| What is the generic name? | Oseltamivir phosphate | Baloxavir marboxil |
| What form(s) does the drug come in? | Oral tablet
Powder for oral suspension |
Oral tablet
Powder for oral suspension |
| What is the standard dosage? | Treatment of influenza:
13 years or older: 75 mg twice daily for 5 days 1 to 12 years old: Dosage depends on weight, twice daily for 5 days 2 weeks to less than 1 year old: 3 mg/kg twice daily for 5 days Prevention of influenza: 13 years and older: 75 mg once daily for at least 10 days 1 to 12 years old: Dosage depends on weight, once daily for 10 days |
Treatment or prevention of influenza:
5 years and older with a body weight of less than 20 kg: 2 mg/kg as a single dose (oral suspension only) 5 years and older with a body weight of 20 to less than 80 kg: 40 mg taken as a single dose 5 years and older with a body weight of at least 80 kg: 80 mg taken as a single dose |
| How long is the typical treatment? | Treatment of influenza: 5 days
Prevention of influenza: 10 days *Preventative treatment during a community outbreak may last up to 6 weeks |
Treatment or prevention of influenza: 1 day with a single dose |
| Who typically uses the medication? | Treatment of influenza: Adults, children, and infants 2 weeks of age and older
Prevention of influenza: Adults, and children 1 year of age and older |
Treatment of influenza: Otherwise healthy adults and children 5 years of age and older
Or Adults and children 12 years and older at high risk of influenza complications Prevention of influenza: Adults and children 5 years and older |
Conditions treated by Tamiflu and Xofluza
Both Tamiflu and Xofluza are used as antiviral treatments for influenza. They are most effective when given at the first sign of symptoms and within 48 hours after symptoms appear.
Tamiflu and Xofluza can also be used to help prevent the flu in those in close contact with an infected individual. People with a higher risk of flu complications include those living in an area with a viral outbreak or those with a compromised immune system because of underlying medical conditions.
As antiviral treatments, Tamiflu and Xofluza are ineffective against fungal, parasitic, or bacterial infections. Use the following table to compare the approved medical uses and off-label uses of Tamiflu and Xofluza.
| Tamiflu | Xofluza | |
| Influenza A/H1N1 treatment | Yes | Yes |
| Influenza A/H3N2 treatment | Yes | Yes |
| Influenza B treatment | Yes | Yes |
| Influenza A/H1N1, influenza A/H3N2, and influenza B prevention | Yes | Yes |
Is Tamiflu or Xofluza more effective?
According to clinical trials, both Tamiflu and Xofluza are effective at alleviating influenza symptoms faster than if you were to take a placebo or nothing at all. In a clinical review, when compared with a placebo, Tamiflu was found to reduce the time to symptom improvement by around 17 hours. In a phase-2 trial for Xofluza, Xofluza shortened the time to symptom relief by around 23 to 28 hours. In addition, the phase-3 clinical trial, also known as the CAPSTONE-1 trial, found that Xofluza had a faster time to alleviate symptoms than placebo, with a difference of around 27 hours.
When Tamiflu and Xofluza were compared in the CAPSTONE-2 trial, Xofluza appeared more effective than Tamiflu with a shorter time to symptom improvement: 73 hours with Xofluza versus 81 hours with Tamiflu. Xofluza also shortened the time of viral shedding, or being contagious, to 48 hours versus up to 96 hours with placebo or Tamiflu. This clinical study enrolled over 2,000 participants and included patients aged 12 years and older.
While Xofluza appears more effective, viral resistance may be a concern. There were signs of viral resistance to Xofluza in around 2% of patients in the phase 2 trial and approximately 10% of patients in the phase 3 trials.
Coverage and cost comparison of Tamiflu vs. Xofluza
Tamiflu can be purchased with a prescription and is typically covered by most commercial insurance, Medicare, and Medicaid plans. It is available in both brand and generic versions. A 10-day supply of brand-name Tamiflu capsules can cost between $155 to $170 without insurance. A 10-day supply of generic oseltamivir capsules can cost between $20 and $50. You may be able to use a SingleCare discount coupon for cost savings on Tamiflu at participating pharmacies.
Xofluza is also purchased with a prescription and is covered by most commercial insurance, Medicare, and Medicaid plans. It is only available as a brand-name pill and may have higher prescription costs than Tamiflu. Out-of-pocket costs for Xofluza can be between $150 and $180. Check if you can use a SingleCare discount coupon to save on Xofluza at your nearest pharmacy.
| Tamiflu | Xofluza | |
| Typically covered by insurance? | Yes, depending on the plan | Yes, depending on the plan |
| Typically covered by Medicare? | Yes, depending on the plan | Yes, depending on the plan |
| Standard dosage | 75 mg twice daily for 5 days | One 40 mg tablet |
| Typical Medicare copay | $10 – $200 | $30 – $170 |
| SingleCare cost | $30 | $160 |
Common side effects of Tamiflu vs. Xofluza
Tamiflu and Xofluza share similar side effects, such as nausea and headache. Other common side effects of Tamiflu include vomiting and pain. Other common side effects of Xofluza include diarrhea, inflammation of the lung airways (bronchitis), and inflammation of the sinuses (sinusitis). Although Xofluza may have more possible side effects than Tamiflu, side effects may occur more frequently with Tamiflu.
Both Tamiflu and Xofluza may cause more serious side effects, such as skin or hypersensitivity reactions. These allergic reactions can start as rashes and become worse over time. There have also been reports of psychiatric events such as delirium, hallucinations, and abnormal behavior in those taking Tamiflu. These psychiatric events have mostly been reported in children from Japan.
| Tamiflu | Xofluza | |||
| Side Effect | Applicable? | Frequency | Applicable? | Frequency |
| Nausea | Yes | 8-10% | Yes | 2% |
| Vomiting | Yes | 2-8% | No | – |
| Headache | Yes | 2-17% | Yes | 1% |
| Diarrhea | No | – | Yes | 3% |
| Bronchitis | No | – | Yes | 3% |
| Sinusitis | No | – | Yes | 2% |
Source: DailyMed (Tamiflu), DailyMed (Xofluza).
Drug interactions of Tamiflu and Xofluza
Tamiflu and Xofluza can interact with the flu vaccine—specifically, the live attenuated influenza vaccine. Due to their antiviral effects, Tamiflu and Xofluza can reduce the efficacy of the flu vaccine. Therefore, the live influenza vaccine should not be given within 14 days before or two days after Tamiflu or Xofluza administration.
Xofluza may interact with medications or products that contain polyvalent cations. These include dairy products, laxatives, antacids, and oral supplements containing calcium, iron, magnesium, zinc, or selenium. When used with Xofluza, these substances can decrease the level of Xofluza in the body and decrease its effectiveness.
| Tamiflu | Xofluza | |
| Live attenuated influenza vaccine | Yes | Yes |
| Polyvalent cation-containing medications (products containing calcium, iron, magnesium, selenium, zinc, etc.) | No | Yes |
Warnings of Tamiflu and Xofluza
Tamiflu should be monitored in those with kidney problems. People with kidney impairment may experience higher levels of Tamiflu in the body, leading to possible adverse events. In contrast, Xofluza’s absorption is not known to be affected by kidney function.
Tamiflu and Xofluza are not recommended for anyone with a known allergy to their active ingredients. Tamiflu and Xofluza have not been heavily studied in pregnancy. Their use in pregnant women should be evaluated by a healthcare provider as the benefits may outweigh the possible risks.
Frequently asked questions about Tamiflu vs Xofluza
What is Tamiflu?
Tamiflu (oseltamivir) is an antiviral medication that treats or prevents the flu. It works as a neuraminidase inhibitor that blocks the spread of influenza A and B in the body. Using Tamiflu can shorten the time it takes for flu symptoms to improve. It was developed by Genentech and is usually taken twice daily for five days.
What is Xofluza?
Xofluza (baloxavir marboxil) is an antiviral medication that can treat or prevent the flu. It is a PA endonuclease inhibitor that stops the influenza virus from copying itself in the body. Like Tamiflu, it can shorten the time to symptom improvement. Xofluza was developed by Shionogi Pharma and is prescribed as a single dose for flu treatment or prevention.
Are Tamiflu and Xofluza the same? / What are the key differences between Tamiflu and Xofluza?
Tamiflu and Xofluza are both antiviral medications. But they are not the same. Although they improve flu symptoms, they work differently and have different side effects.
Is Tamiflu or Xofluza better?
Tamiflu and Xofluza are both effective against the influenza virus. Xofluza is a newer drug that has been shown to improve flu symptoms faster than Tamiflu. It also only needs to be taken as a single dose, which some people may prefer. Consult a doctor or healthcare provider for medical advice and more information on the best treatment.
Who can use Tamiflu and Xofluza?
Tamiflu and Xofluza are used to treat acute uncomplicated influenza in adult and pediatric patients. These prescription medications are often used during influenza season to treat the flu or prevent severe illness from the flu. Tamiflu is approved to treat the flu in adults and children two weeks and older and prevent the flu in adults and children one year and older. Xofluza is approved to treat or prevent the flu in otherwise healthy adults, children five years and older, and high-risk individuals 12 years and older. Both medications are generally safe in older adults 65 years and older. Consult a healthcare provider if you have other medical conditions or are pregnant or breastfeeding.
Can you take Xofluza with Tamiflu?
No. It is not recommended to take Xofluza and Tamiflu together. These drugs are prescribed as separate, individual options for the flu. Depending on your medical history and overall condition, one drug may be preferred over the other.
