Ask the Harvard Experts: Do I Need an Antiviral Drug to Treat Flu?

Ask the Harvard Experts: Do I Need an Antiviral Drug to Treat Flu?

Q: If I get flu-like symptoms, how do I know if it’s really influenza or something else? If it really is the flu, I would prefer to take an antiviral medication right away.

A: Your question is very timely because the U.S. Food and Drug Administration (FDA) is currently evaluating whether to make the antiviral drug oseltamivir (Tamiflu) available over-the-counter.

Right now you would still need to call your doctor if you thought you needed oseltamivir because it still requires a prescription. But in the future, you will likely be able to make the decision on your own.

Classic symptoms of influenza that differentiate it from a cold or viral bronchitis are fever greater than 101 degrees, chills, headache and brutal body ache. People often describe it as being run over by a truck.

However, for many people with influenza, they only experience fatigue, malaise, sore throat and cough. So, it can be hard to differentiate the real flu from an upper respiratory infection when these are the only symptoms.

Many doctors will prescribe Tamiflu or other antiviral drug over the phone when a person has classic symptoms during flu season. Or your doctor may ask you to come to the office for evaluation and perhaps perform a rapid flu test if what you’re describing is not straightforward or you are at high risk for a complication.

Tamiflu is a tablet taken by mouth twice per day for five days. There are other antivirals available include zanamivir (Relenza), baloxavir (Xofluza) and peramivir (Rapivab).

Relenza is a powder that is inhaled twice per day also for five days. Xofluza, the newest drug for influenza, is just a single dose. Rapivab is also a single dose, but must be given intravenously in the office. Xofluza and Rapivab are more expensive options. So far there is no evidence that any of them is more effective than generic oseltamivir.

All of these antivirals should be started within two days of the onset of symptoms. On average, they can reduce symptoms by about one day. Some studies suggest that these drugs when taken within 48 hours of onset of symptoms may also reduce the risk of pneumonia and other complications that require hospitalization.

Having the option of taking an antiviral drug to treat influenza should never be considered as an alternative to the flu shot. The flu shot is still the best way to prevent the illness.

(Howard LeWine, MD, is an internist at Brigham and Women’s Hospital in Boston and assistant professor at Harvard Medical School. For additional consumer health information, please visit