Should You Use Antiviral Medications for the Flu?

Antiviral medications are a class of drugs that are typically used to prevent or shorten the duration of the influenza virus. They are considered the second line of defense against the flu.

According to the Centers for Disease Control and Prevention, there are currently four antiviral medications are that currently FDA-approved to treat the flu in the United States. They include Tamiflu (oseltamivir phosphate), Relenza (zanamivir), Rapivab (peramivir), Xofluza (baloxavir marboxil). Two other medications, amantadine and rimantadine, have been shown to target influenza A viruses, but the flu viruses that make people sick are extremely resistant to them, so these two medications are not recommended to prevent or treat influenza at this time.

When to Use Them

Antiviral medications are available by prescription only. If you are diagnosed with the flu, your health care provider may prescribe antiviral medications for you if:

  • You have the flu and want to shorten the duration of the symptoms. In this case, the medication must be started within the first 48 hours of symptoms to be effective.
  • You are in close contact with someone who has the flu, such as a family member (paired with the vaccine)
  • There is a widespread outbreak in your community and you or someone you are close to are at high risk for complications (paired with the vaccine)
  • You may be exposed to the flu and the flu shot is not effective, or you cannot get it because of an allergy

How to Use Antiviral Medications

Each medication is given in a different way and may not be appropriate for certain groups of people. Your healthcare provider can determine which medication is right for you and your situation.

Tamiflu is available as a pill or liquid, Relenza is an inhaled powder, Xofluza is another pill, and Rapivab is given through an IV. They are given for different lengths of time and at different doses depending on age and what the medicine is being used for (treatment or prevention).

How They Work

Antiviral medications have the best chance of success if you begin taking them as soon as you've received your flu diagnosis. If you start treatment within two days of experiencing symptoms, these drugs can reduce your fever and symptoms and speed up your recovery by about one day.

Antiviral medications can also lessen the risk of complications including childhood ear infections, respiratory issues that would require complications, and potential hospitalization for adult patients.

For those at a higher risk of serious flu complications, receiving early antiviral treatment can lessen the chance of becoming severely ill and requiring a hospital visit. Research has even shown that early antiviral treatment can reduce someone's risk of death from the flu.

Who Should Take Them

While people who are mildly ill and not at high risk of flu complications may be treated with antiviral medications, it's not always necessary. However, those who are severely ill or hospitalized with the flu, or those at risk of serious complications because of their age or certain health conditions should receive these drugs as soon as possible once they develop flu symptoms.

Health and Age Factors Known to Increase Risk of Serious Flu Complications

  • Asthma
  • Neurologic and neurodevelopment conditions
  • Blood disorders
  • Chronic lung disease
  • Endocrine disorders
  • Heart disease
  • Kidney disorders
  • Liver disorders
  • Metabolic disorders
  • People who are obese with a body mass index of 40 or higher
  • People younger than 19 years of age on long-term aspirin- or salicylate-containing medications
  • People with a weakened immune system due to disease (such as people with HIV or AIDS, or certain cancers) or medications (such as cancer treatments, chronic corticosteroids or other drugs that suppress the immune system)

Other groups known to be at a higher risk of experiencing flu complications include:

  • Adults 65 years and older
  • Children younger than two years old
  • Pregnant women and women up to two weeks after the end of pregnancy
  • American Indians and Alaska Natives
  • People who live in nursing homes and other long-term care facilities

It's also worth noting that children younger than five years old are considered at high risk for serious flu complications, but the highest risk is for those younger than two years old, with the highest hospitalization and death rates among infants younger than six months old.

Potential Side Effects

According to the CDC, side effects can vary for each antiviral medication covered here. However, the most common side effects of oseltamivir are nausea and vomiting, Zanamivir can cause bronchospasm, and peramivir can cause diarrhea. You should talk to your health care provider about other potential side effects, or review the medication package insert for more information. Additionally, combining them with other medications may reduce efficacy, so talk to your doctor before doing that as well.

A Word From Verywell

Antiviral medications can be very useful in helping to prevent or shorten the duration of the flu. However, they should not replace flu vaccines as your primary means of prevention. Because all of the antiviral medications are available only by prescription, it is important to see your healthcare provider if you believe you have the flu or may need antiviral medications to prevent it. Only your healthcare provider can determine what is best for you and your situation.

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Article Sources

Verywell Health uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read our editorial policy to learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.
  1. Wang C, et al. Prompt oseltamivir therapy reduces medical care and mortality for patients with influenza infection. Medicine (Baltimore). 2015 Jul; 94(27): e1070. doi:10.1097/MD.0000000000001070

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