Tamiflu is a prescription medication for the treatment of influenza, or flu, in children and adults. Possible side effects of Tamiflu include nausea, vomiting, and more.

The Food and Drug Administration (FDA) approved the use of Tamiflu in 1999.

In 2009, governments across the world stockpiled the drug in response to the worldwide spread of the H1N1, or “swine flu” strain of influenza.

However, recent research has shed doubt on how well Tamiflu works and raised concerns over possible side effects.

This article outlines the current evidence regarding the efficacy and safety of Tamiflu in children.

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Influenza antivirals are drugs that shorten the duration of flu symptoms. Tamiflu is the brand name for the antiviral drug oseltamivir.

Oseltamivir belongs to the neuraminidase inhibitor (NAI) class of antivirals.

Neuraminidase is an enzyme that allows a virus to replicate inside the body. NAIs block these enzymes and help prevent the virus from replicating.

A doctor may prescribe Tamiflu to reduce severe flu symptoms in children as young as 2 weeks old, or to help prevent flu in children aged 1 year or older.

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Tamiflu can cause a variety of side effects. Most of the common side effects are not serious, but rarer and more serious side effects are possible.

Common side effects

According to the FDA, the most common side effects of Tamiflu are nausea and vomiting. Both tend to occur within the first 2 days of treatment.

Taking Tamiflu with food may reduce the risk of an upset stomach.

Other potential side effects

Other side effects of oseltamivir may include:

In some cases, oseltamivir may cause more serious side effects. A child or adult who experiences any of the following should see a doctor immediately or contact the emergency services:

  • allergic skin rash, hives, or blisters
  • itching
  • swelling of the face or tongue
  • difficulty breathing or swallowing
  • mouth sores
  • hoarseness
  • speech problems
  • confusion
  • shaky movements
  • hallucinations

Neuropsychiatric side effects

A 2012 review investigated the risk of neuropsychiatric side effects among children and adults receiving oseltamivir. Neuropsychiatric effects are those that healthcare professionals link to a person’s mental health and the nervous system.

According to the review, between September 2007 and May 2010, some 1,330 people across the globe experienced what it terms neuropsychiatric adverse events (NPAEs) while taking oseltamivir.

A total of 1,072 of these NPAEs occurred in children aged 16 years or under.

The most common NPAEs among children were abnormal behavior, delusions, and perceptual disturbances.

However, the authors suggested that the NPAEs may not have been due to oseltamivir but were a symptom of the influenza virus.

The authors based this conclusion on the following observations:

  • NPAEs also occurred among people who did not take oseltamivir.
  • Most cases of NPAEs happened when people were experiencing fever.
  • Fever can directly cause psychiatric symptoms.

For some children, the benefits of taking Tamiflu may outweigh any potential risks. This includes children with severe flu symptoms and those with the following underlying medical conditions:

The flu is more likely to cause complications in children who have one or more of the above conditions.

Research suggests that whether Tamiflu works differs for otherwise healthy individuals with mild flu and those with severe flu or other underlying health issues.

Effects in healthy individuals

Early clinical trials suggested that Tamiflu was highly effective in treating influenza among otherwise healthy people. The FDA’s approval of the drug followed in 1999.

A 2014 Cochrane review reinvestigated the data. The authors found that the drug reduced the duration of flu symptoms by less than a day.

Oseltamivir, the generic name for Tamiflu, had no significant effect on whether doctors have to admit people to hospital subsequently. The drug did not significantly reduce serious complications of influenza, such as bronchitis, sinusitis, and middle ear infections. Some people also experienced side effects when taking the drug.

The authors of this review suggested that oseltamivir helps treat the symptoms of flu but does not prevent the virus from replicating.

Roche, the company which marketed the drug original, jointly funded a separate study that disagreed with this claim and supported the use of NAIs.

Effects in hospitalized patients

In 2009, countries around the world experienced an outbreak of the H1N1 or “swine flu” virus. For the first time, researchers were able to collect observational data on the efficacy of Tamiflu in hospitalized patients.

A 2013 study analyzed the medical records of 784 children whom doctors had hospitalized for flu.

Of these, 8 percent who did not receive NAI treatment died as a result of the infection. This was 2 percent more than the number of children who died after being treated with an NAI.

Also, children who received NAI treatment earlier in the progression of the illness were more likely to survive.

Authors of a 2016 review suggested that data from people with mild symptoms should not be used to determine whether NAIs are effective for those with severe cases of the flu.

Typically, in otherwise healthy people, the body’s immune system can fight off the influenza virus. In people with weaker immune systems, antiviral drugs may boost the immune system and help rid the body of the virus.

Zanamivir and peramivir are two alternative NAIs that are suitable for children.


Zanamivir (Relenza) is a powder that a person inhales by using a special inhalation device.

A doctor may prescribe zanamivir to treat the flu in children aged 7 years and above or to prevent the flu in those of 5 years and above.

Zanamivir is not suitable for individuals with asthma or other respiratory problems, as it increases the risk of bronchospasm where the muscles within the lungs tighten and restrict airflow.

According to the Centers for Disease Control and Prevention (CDC), fewer than 5 percent of people participating in clinical trials have experienced side effects in response to inhaling zanamivir.

Despite this, possible side effects may include:

  • diarrhea
  • nausea
  • headache
  • dizziness
  • sinusitis
  • nasal symptoms
  • cough
  • bronchitis
  • ear, nose, and throat infections


Peramivir is an intravenous drug with the trade name Rapivab. A doctor can prescribe peramivir to help treat the flu but not to prevent it.

Peramivir can help treat the flu in children aged 2 years and above. It is particularly convenient for children who are unable to take antivirals orally or via inhalation.

According to a 2016 review, the side effects of peramivir are more common among children, but they tend to be mild to moderate.

Side effects in children include:

  • abnormal behavior
  • cough
  • fever
  • gastrointestinal problems

Research shows that Tamiflu tends to be more beneficial for children and adults with severe flu symptoms and those with serious underlying health conditions.

The benefits of Tamiflu for otherwise healthy individuals with mild symptoms should be weighed against the risk of potential side effects.

Relenza (zanamivir) and Rapivab (peramivir) are two Tamiflu alternatives that are suitable for children. A doctor will decide which influenza antiviral medication is most appropriate on a case-by-case basis.