When Is Tamiflu Worth Taking?

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The flu is always a nasty foe—and it’s particularly vicious this year. According to the U.S. Centers for Disease Control and Prevention (CDC), there have been at least 12 million flu infections since the fall in the U.S., leading to 160,000 hospitalizations and 6,600 deaths.

Dr. Mahesh Polavarapu, medical director of emergency medicine at NewYork-Presbyterian Westchester, has mostly seen influenza A this year, a strain that causes more serious illness than influenza B. “If you’re getting flu-like symptoms, and you’re like, ‘This feels worse than before,’ you're not wrong,” he says. “It’s pretty harsh this year.”

Fortunately, there are ways to alleviate at least some of the misery of the flu (besides, of course, getting your annual flu shot before you get sick). Doctors often prescribe Tamiflu, an antiviral that can treat both influenza A and B. Here’s what to know about how it works—and whether it might be right for you.

How does Tamiflu work?

Most people have flu symptoms for three to seven days. Tamiflu can shorten that by about 24 hours by blocking the virus from replicating in your body. “It’s basically stopping the virus from multiplying or shedding any more than it already has,” Polavarapu says. (Antibiotics, which treat bacterial infections, don’t work against a viral infection like the flu.)

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Tamiflu starts working after the first dose, and within a day or two, it will have built up in your body enough to make a noticeable difference. But timing is crucial—you need to start taking it within 48 hours of symptom onset. “I tell patients to consider it a way to reduce the duration of their symptoms by hopefully a day,” Polavarapu says.Tamiflu (sold under the generic name oseltamivir) can be prescribed as a pill or in liquid form, and most people take 75 mg twice a day for five days, he adds.

Who might benefit from taking Tamiflu?

You’re most likely to benefit from Tamiflu if you have risk factors that predispose you to serious influenza infection. That includes being 65 or older, under 2, pregnant, or immunocompromised, or having a chronic condition like diabetes, heart disease, or asthma. Research suggests that starting Tamiflu within two days of developing symptoms can reduce the risk of death from a serious case of the flu; it also lowers ICU admission rates among hospitalized adults.

Tamiflu is also available to people outside of these higher risk groups. It can be taken by anyone else who’s at least 2 weeks old and who’s had flu symptoms for no more than two days.

Is it really worth it just to feel better one day sooner? 

“Flu makes you feel very crummy, and so a day less is certainly better than a day more,” says Dr. Helen Chu, a professor of medicine, allergy, and infectious diseases at the University of Washington. “But it’s not like a dramatic difference, so I understand why people have reservations about it.”

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Whether it’s right for you comes down to your own priorities. “You have to weigh your pros and cons,” she says. “You have to go pick up the medicine”—an inconvenient task when you’re sick—“and it can make people nauseated.” Yet there’s another, often significant benefit to keep in mind: Tamiflu can be a way to help keep your family members safe.

Does Tamiflu make you less contagious?

You can still spread the flu to other people while you’re on Tamiflu, Chu says. Scientists aren’t sure exactly how much less contagious it makes you. However, research suggests that the antiviral helps prevent household outbreaks. In one study, it reduced secondary infections among people who lived in the same house by 50% if those who weren’t sick yet started Tamiflu within 24 hours. “You can use it to stop transmission,” Chu says. “If someone in your house has the flu, that person can take it for treatment, but you can also take it to prevent yourself from acquiring the infection.”

Can you take Tamiflu to prevent getting the flu?

If you haven’t been exposed to the flu and you’re simply desperate to avoid catching it, it doesn’t make sense to take Tamiflu. Your doctor won’t prescribe it for that reason—it’s not like a vitamin you might take in hopes of bolstering immune health. “It's not a preventive measure,” Polavarapu says. However, if you have been exposed to the flu—especially by someone in your household—many doctors will consider prescribing a prophylactic dose to lower your chance of infection.

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Keep in mind, however, that Tamiflu isn’t a guaranteed way to stay healthy, so you still need to practice other healthy behaviors when flu is in your house: washing your hands frequently, wearing a face mask, cleaning high-touch surfaces like doorknobs and light switches. And for family members with the flu, don’t go out unless you absolutely need to: The CDC recommends staying home until your symptoms have been improving and you haven't had a fever for at least 24 hours.

How do I know if I need Tamiflu?

Thanks to the rise of at-home tests, it’s now easy to confirm whether you have the flu without even leaving your house. “The way the flu works, unlike some other viruses, is that it really hits you like a truck,” Chu says. “You're feeling fine, and then suddenly you just need to crash.” If you’re overcome with the urge to climb into bed, and your entire body hurts, it’s time to test, she says. If it turns out you do in fact have the flu, call your doctor and ask about Tamiflu. “The earlier you start it, the better,” she adds—so don’t spend too much time vacillating about the decision.

When is it too late to take Tamiflu?

The gold standard is to start Tamiflu within two days of symptom onset; if you’ve been sick longer than that, your doctor probably won’t prescribe it for you. But there are some exceptions. If you’re immunocompromised or so sick that you’re hospitalized with the flu, “then we start it any time,” Chu says. “Most people clear the virus very quickly, but people who have suppressed immune systems are shedding it for much longer, so you can start Tamiflu later on.”

Can kids take Tamiflu?

Yes—but at a slightly smaller dose than teens and adults. Children who are 2 weeks to 12 years old take a twice-daily dose based on their weight. As the CDC notes, taking Tamiflu curbs the incidence of ear infections in kids with the flu, and may also reduce more serious complications like pneumonia and hospitalization.

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Does Tamiflu have any side effects?

Tamiflu is “a safe medication,” Polavarapu says, with a track record spanning more than two decades. It was approved by the U.S. Food and Drug Administration in 1999, and the generic version, oseltamivir phosphate, was approved in 2016.

Still, like most medications, there’s a risk of side effects. You might feel nauseous and even vomit if you take Tamiflu. Diarrhea is also possible, though less common. “Essentially what I tell patients is that the medicine itself can make you feel kind of crummy, particularly the nausea,” Polavarapu says. Sometimes, if a patient doesn’t tolerate it well, he prescribes anti-nausea medication alongside it. Ideally, he says, treating one set of symptoms won’t cause another set to pop up, but it’s smart to be aware what kind of side effects are possible.

“Medications like antivirals aren’t always the answer,” he says. “They’re an answer in a specific time duration,” and for certain people, but they’re not a magic, flu-dissipating bullet—and whether they’re right for you depends on your own unique circumstances.

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