oseltamivir, Tamiflu

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GENERIC NAME: oseltamivir


DRUG CLASS AND MECHANISM: Oseltamivir is an oral medication used for treating and preventing the "flu." It is similar to zanamivir (Relenza). Oseltamivir suppresses and decreases the spread of influenza A and B viruses, the viruses responsible for the flu. It does this by blocking the action of neuraminidase, an enzyme produced by the viruses that enables the viruses to spread from infected cells to healthy cells. By preventing the spread of virus from cell to cell, the symptoms and duration of influenza infection are reduced. On average, oseltamivir reduces the duration of symptoms by one and a half days if treatment is started within forty-eight hours of the beginning of symptoms. The FDA approved oseltamivir in October 1999.



PREPARATIONS: Capsules: 30, 45, and 75 mg. Suspension: 6 mg/ml and 12 mg/ml

STORAGE: Oseltamivir should be stored at room temperature, 15C to 30 C (59 F to 86 F).

PRESCRIBED FOR: Oseltamivir is used for the treatment of uncomplicated infections with the influenza viruses (A and B) in adults and children (including infants under age 1 who have had symptoms of the flu such as stuffy nose, cough, sore throat, fever, and body aches, for no longer than two days. It is not approved to prevent the flu in this age group.) within two days of the beginning of symptoms. Oseltamivir also is used for preventing the flu in healthy individuals 1 year and older, but it is not a substitute for flu vaccine. It also is used off-label for prevention and treatment of H1N1 (Swine Flu). During the H1N1 outbreak of 2009, the FDA approved emergency use of oseltamivir for children less than 1 year old.

DOSING: Oseltamivir is administered orally. For the best results, treatment should begin within 2 days of symptom onset or exposure.

  • The recommended dose for treating adults with flu is 75 mg twice daily for five days.
  • Children are treated with 30-75 mg twice daily for five days. Dosing depends on body weight.
  • The adult dose for prevention of flu is 75 mg daily for 10 days. Children receive 30-75 mg once daily for 10 days.

DRUG INTERACTIONS: Oseltamivir potentially may interfere with the action of the live attenuated flu vaccine that is given by injection because oseltamivir prevents viral replication. Therefore, live attenuated flu vaccine should not be administered within two weeks before or 48 hours after administration of oseltamivir.

PREGNANCY: The Centers for Disease Control (CDC) recommends use of oseltamivir for treating flu in pregnant women.

NURSING MOTHERS: The CDC recommends that women with flu who have recently given birth may be treated with oseltamivir. Oseltamivir is approved for use in children one year old and older, and available evidence suggests that the risk of adverse events is low when oseltamivir is used in children less than 1 year old.

SIDE EFFECTS: The most frequent side effects of oseltamivir are nausea, vomiting, diarrhea, bronchitis, abdominal pain, headache and dizziness. Administering oseltamivir after meals helps reduce nausea. Other reported adverse events include allergic reactions, skin reactions, seizures, behavioral disturbances, and aggravation of diabetes.


Tamiflu Prescribing Information, 2008. Roche Laboratories.

CDC. "Updated Interim Recommendations for the Use of Antiviral Medications in the Treatment and Prevention of Influenza for the 2009-2010 Season."

WebMD.com. FDA Approves Tamiflu for Infants.

Medically Reviewed by a Doctor on 1/10/2013

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