Tamiflu: Should You Worry About Side Effects?

Tamiflu: Should You Worry About Side Effects?

If you have the flu, this antiviral drug can be a big help—but some have reported hallucinations and suicidal thoughts.

Flu activity typically begins in October, peaking between the months of December and February. And as you likely know, the flu can cause some pesky symptoms, such as a fever, cough, sore throat, fatigue, and more serious complications, like pneumonia.    

If you do become sick with the flu, you can ask your doctor for an antiviral drug prescription, which could shorten the misery. 

But you may have heard some scary stuff about the most popular antiviral, Tamiflu (oseltamivir)—that it can spark unusual, even life-threatening behavior. In 2018, an Indiana family reportedly blamed the drug for the suicide of their teenaged son. That same year, a family in Texas told the media that their daughter, after taking Tamiflu, began hallucinating, and was about to jump out a window when her mother rescued her.

Are the side effects of Tamiflu something to worry about? Here's what you should know about this antiviral medication—and how to put it all into perspective.

Your antiviral options
Four antiviral drugs to treat flu are approved by the FDA and recommended by the Centers for Disease Control and Prevention (CDC). They are:

  • Tamiflu (oseltamivir)
  • Relenza (zanamivir)
  • Rapivab (peramivir)
  • Xofluza (baloxavir marboxil)

Of these, Tamiflu is the most popular, according to Amesh Adalja, MD, a senior scholar at the Johns Hopkins Center for Health Security and a spokesperson for the Infectious Diseases Society of America. It can be given in liquid or capsule form. A generic version of oseltamivir is also available.

Relenza is in inhaler form, he says, and can be cumbersome to use. Rapivab is given intravenously, usually to someone so sick they can't take medicine by mouth. And Xofluza is a pill given as a single dose. Two other antiviral drugs, amantadine (generic) and rimantadine (Flumadine and generic versions) have been approved by the FDA, but the CDC doesn't currently recommend them, as they don't work well against flu viruses circulating recently.

What Tamiflu does
Tamiflu works by blocking the action of an enzyme on the surface of the flu virus, restraining the virus from spreading to other cells, according to Genentech, its maker.

Tamiflu isn't just meant for people who want to save their sick time. It is especially recommended for those at risk of complications, such as pneumonia. This includes young children, older adults and those with other major health issues, like heart disease or diabetes. Doctors use their judgment in prescribing it to otherwise healthy people.

While the antiviral shortens the course of the flu by about a day, the drugs may also prevent complications of the flu, such as ear infections in children and pneumonia—and even death—in adults, according to the CDC.

The lowdown on side effects
"In general, Tamiflu is a well-tolerated drug," Dr. Adalja says. Nausea and vomiting are the most common side effects, and you can be given medicine to ease the vomiting. However, there are those rare reports of hallucinations, confusion and other unusual behavior, which are of concern to patients and doctors.

In 2005, the FDA reviewed reports of teens in Japan who experienced these symptoms after taking Tamiflu; these included reports of 12 deaths. The agency concluded the evidence could not prove the drug was responsible, and Genentech says there hasn't been a connection established between Tamiflu and the events.

Genentech warns that those with flu, especially children and teens, may be at an increased risk of seizures, confusion or abnormal behavior soon after they get sick. These side effects may occur after starting to take Tamiflu or may start when the patient has the flu but doesn't take Tamiflu, the company says.

Adalja agrees no cause and effect can be proven. It is possible, he says, that something about having the flu—by itself—may trigger these reactions in some people, with younger age groups perhaps more vulnerable. 

What's more, Adalja says he has never seen cases of psychiatric side effects from Tamiflu. "I am a pretty liberal prescriber of Tamiflu," he adds. ''We do know Tamiflu is very well tolerated by the vast majority of people."

Even so, he says, if you take the drug, you should be sure someone watches you for signs of abnormal behavior. If any worrisome or unusual behavior occurs, get medical help right away. 

Medically reviewed in February 2018. Updated in September 2019. 

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