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How Does Tamiflu Work?

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Flu is a respiratory infection caused by the influenza virus. According to the Centers for Disease Control and Prevention (CDC), the flu can cause up to 40 million illnesses, 700,000 hospitalizations, and 50,000 deaths each year in the United States. Flu symptoms commonly include fever, chills, cough, sore throat, muscle aches, and body aches. Sometimes the flu can develop into a more severe illness like pneumonia. In some cases, it may be appropriate to use an antiviral medication called Tamiflu to treat the flu. Continue reading to learn how this medication works and why your doctor might prescribe Tamiflu.

What is Tamiflu? Can it relieve sore throat from the flu virus?

Tamiflu is the brand name of an antiviral drug called oseltamivir phosphate. It is a prescription medication available in both generic and brand name forms. 

Tamiflu is used to treat flu illnesses caused by influenza A and B viruses. The FDA has approved adults and children 2 weeks of age and older to take Tamiflu. When used along with other flu treatments, Tamiflu can relieve symptoms caused by a flu virus. 

Taking Tamiflu can also prevent the flu in adults and children ages 1 year and older. However, the frequency and duration of Tamiflu are different for prevention and treatment. You should take this medicine exactly as instructed by your healthcare provider.

Is Tamiflu an antibiotic?

No, Tamiflu is an antiviral medication that kills the flu viruses. Antibiotics are used to treat bacterial infections, which is why antibiotics will not be prescribed by your doctor. 

How exactly does Tamiflu work scientifically?

Oseltamivir (Tamiflu) works by blocking an enzyme called neuraminidase which is present on the surface of the flu virus. The virus needs this enzyme to move around the human respiratory tract. By blocking this enzyme, Tamiflu prevents the virus from exiting an infected cell, multiplying, and infecting more cells. Simply put, Tamiflu reduces flu symptoms by preventing the virus from infecting other cells and multiplying. 

How to use Tamiflu?

The usual adult dose of Tamiflu to treat the flu is 75 mg twice a day for five days. It is important to complete the full course of treatment as prescribed. Doctors sometimes prescribe a longer treatment course for some people. 

It is worth noting that Tamiflu is most effective when the first dose is taken within 48 hours of symptom onset (preferably at the first sign of flu symptoms). This makes it easier for the drug to prevent the virus from multiplying and spreading in the body. 

However, some people at high risk of developing severe symptoms or flu complications may be prescribed Tamiflu even if two days have passed since symptom onset. These people include pregnant women and people with asthma, diabetes, heart disease, or a weak immune system.

How quickly does Tamiflu work?

Tamiflu is absorbed from the stomach and immediately starts working to attack the virus, causing flu symptoms. However, there is still time between beginning the medication and seeing results. Remember that you should finish the 5-day course of treatment even if you have started feeling better. 

Does Tamiflu shorten flu symptoms?

Tamiflu will not eliminate all of your flu symptoms, but it can shorten the duration of your illness. The usual duration of a flu illness is 3-7 days, and Tamiflu can shorten it by 1-2 days. 

Can you get Tamiflu over the counter?

No, Tamiflu is a prescription medication, and you cannot buy it over the counter. You should take this medication only if advised by your doctor. 

What is so bad about Tamiflu?

There is nothing bad about this medicine. It is a very safe medication and is FDA approved for use in babies as young as 2 weeks old. Your healthcare provider can give you more information about the benefits and risks of taking Tamiflu in your specific case. 

You should know that, like most medications, there are potential side effects of Tamiflu. This drug's most common side effects are nausea, vomiting, diarrhea, headache, dizziness, nosebleeds, eye redness, and insomnia. However, it can also cause more serious side effects such as hallucinations in a small number of people.

Is Tamiflu a substitute for the flu vaccine?

No, Tamiflu is not a substitute for the flu shot. The CDC recommends that everyone over 6 months old get the flu vaccine every flu season, except in rare cases. 

While taking Tamiflu can prevent you from getting the flu if you take it before you get sick, this is not the best way to protect yourself and control the spread of the illness. Tamiflu works for a short period of time against flu infection. In contrast, the flu vaccine works by developing your immune system to fight against the infection for a longer duration. You should take Tamiflu only if recommended by a healthcare provider for treatment or prevention of the flu.

Besides the flu shot, there are other ways to prevent the flu and common cold, especially during flu season. This includes avoiding close contact with sick people, covering your nose and mouth when you cough and sneeze, and washing your hands frequently.


  1. https://www.fda.gov/drugs/postmarket-drug-safety-information-patients-and-providers/tamiflu-consumer-questions-and-answers
  2. https://www.accessdata.fda.gov/drugsatfda_docs/label/1999/21087lbl.pdf
  3. https://www.cdc.gov/flu/about/burden/index.html