Oseltamivir

Generic Name: oseltamivir (os el TAM ih veer)Brand Names: Tamiflu

What is oseltamivir?

Oseltamivir is an antiviral medication that blocks the actions of influenza virus types A and B in your body.

Oseltamivir is used to treat flu symptoms caused by influenza virus in patients who have had symptoms for less than 2 days. Oseltamivir may also be given to prevent influenza in people who may be exposed but do not yet have symptoms. Oseltamivir will not treat the common cold.

Oseltamivir may also be used for other purposes not listed in this medication guide.

What is the most important information I should know about oseltamivir?

Oseltamivir is used to treat flu symptoms caused by influenza virus in patients who have had symptoms for less than 2 days. Oseltamivir may also be given to prevent influenza in people who may be exposed but do not yet have symptoms. Oseltamivir will not treat the common cold.

Before taking oseltamivir, tell your doctor if you have received a nasal flu vaccine within the past 2 weeks, or if you have kidney disease, heart disease, lung disease, or any other serious disease or health problem. Also tell your doctor if you have any condition causing swelling or disorder of the brain.

Treatment with oseltamivir should start as soon as possible when flu symptoms appear, such as fever, chills, muscle aches, sore throat, and runny or stuffy nose.

Take this medication for as many days as it has been prescribed for you even if you begin to feel better. Your symptoms may start to improve before the infection is completely treated. Some people using oseltamivir have had rare side effects of sudden confusion, delirium, hallucinations, unusual behavior, or self-injury. These symptoms have occurred most often in children. It is not known whether oseltamivir was the exact cause of these symptoms. However, anyone using oseltamivir should be watched closely for signs of confusion or unusual behavior. Call a doctor at once if you or the child using oseltamivir has any of these symptoms. Oseltamivir should not be used in place of getting a yearly flu shot. The Centers for Disease Control recommends an annual flu shot to help protect you each year from new strains of influenza virus.

What should I discuss with my healthcare provider before using oseltamivir?

Oseltamivir should not be used in place of getting a yearly flu shot. The Centers for Disease Control recommends an annual flu shot to help protect you each year from new strains of influenza virus.

You should not use this medication if you are allergic to oseltamivir.

Before taking oseltamivir, tell your doctor if you have used a nasal flu vaccine (FluMist) within the past 2 weeks, or if you have:

  • kidney disease;

  • heart disease;

  • lung disease;

  • a condition causing swelling or disorder of the brain; or

  • any other serious disease or health problem.

FDA pregnancy category C. It is not known whether oseltamivir is harmful to an unborn baby. However, not receiving this medication to prevent influenza could be harmful to the baby if the mother becomes infected with a disease that oseltamivir could prevent. Before taking this medication, tell your doctor if you are pregnant. Your doctor will decide whether you should receive oseltamivir, especially if you have a high risk of infection with H1N1 influenza (also called "swine" flu). It is not known whether oseltamivir passes into breast milk or if it could harm a nursing baby. Do not take this medication without telling your doctor if you are breast-feeding a baby. Do not give this medication to a child younger than 1 year old.

How should I take oseltamivir?

Take oseltamivir exactly as your doctor has prescribed it for you. Do not take more of the medication than recommended. Do not take oseltamivir for longer than your doctor has prescribed.

Treatment with oseltamivir should start as soon as possible when flu symptoms appear, such as fever, chills, muscle aches, sore throat, and runny or stuffy nose.

Take the oseltamivir capsule with a full glass of water. Shake the oral suspension (liquid) well just before you measure a dose. To be sure you get the correct dose, measure the liquid with the syringe provided with the medicine. Do not measure the medicine with a regular table spoon. If you do not have the syringe or another medicine dose-measuring device, ask your pharmacist for one.

You may take oseltamivir with or without food. If the medicine upsets your stomach, it may help to take it with food or milk.

To treat flu symptoms: Take oseltamivir every 12 hours for 5 days.

To prevent flu symptoms: Take oseltamivir every 24 hours for 10 days or as prescribed. Follow your doctor's instructions.

Use this medication for the entire length of time prescribed by your doctor. Your symptoms may get better before the infection is completely treated. Tell your doctor if your symptoms do not improve, or if they get worse. Store oseltamivir capsules at room temperature away from moisture and heat. Store oseltamivir liquid in the refrigerator but do not freeze. Throw away any unused liquid after 10 days.

See also: Oseltamivir dosage in more detail

What happens if I miss a dose?

Take the missed dose as soon as you remember. If your next dose is less than 2 hours away, skip the missed dose and take the medicine at the next regularly scheduled time. Do not take extra medicine to make up the missed dose.

What happens if I overdose?

Seek emergency medical attention if you think you have used too much of this medicine.

Overdose symptoms may include nausea and vomiting.

What should I avoid while taking oseltamivir?

Do not use a nasal flu vaccine (FluMist) within 48 hours after taking oseltamivir. Oseltamivir may interfere with the drug action of FluMist, making the vaccine less effective. Follow your doctor's instructions.

Oseltamivir side effects

Stop using oseltamivir and get emergency medical help if you have any of these signs of an allergic reaction: hives; difficulty breathing; swelling of your face, lips, tongue, or throat; a red and blistering or peeling skin rash. Some people using oseltamivir have had rare side effects of sudden confusion, delirium, hallucinations, unusual behavior, or self-injury. These symptoms have occurred most often in children. It is not known whether oseltamivir was the exact cause of these symptoms. However, anyone using oseltamivir should be watched closely for signs of confusion or unusual behavior. Call a doctor at once if you or the child using oseltamivir has any of these symptoms.

Less serious side effects may include:

  • nausea, vomiting, diarrhea;

  • dizziness, headache;

  • nosebleed;

  • eye redness or discomfort;

  • sleep problems (insomnia); or

  • cough or other respiratory symptoms.

This is not a complete list of side effects and others may occur. Call your doctor for medical advice about side effects. You may report side effects to FDA at 1-800-FDA-1088.

Oseltamivir Dosing Information

Usual Adult Dose for Influenza:

75 mg orally twice a day for 5 daysSeverely ill hospitalized patients with 2009 H1N1 influenza virus infection (previously referred to as novel influenza A [H1N1] virus infection): Increasing the dose to 150 mg orally twice a day or extending the treatment duration can be considered.

Usual Adult Dose for Influenza Prophylaxis:

75 mg orally once a dayOseltamivir should be started in anticipation of an outbreak and before or after a known exposure. For maximal effectiveness in an outbreak, the drug should be continued for the entire duration of influenza activity in the community, or at least during the period of peak influenza activity if cost is a concern. However, there are no data on the safety and efficacy of oseltamivir prophylaxis beyond 6 weeks.When used as an adjunct to influenza vaccination, chemoprophylaxis with antiviral agents may be given for approximately 2 weeks to provide interim protection until development of adequate antibody response. While no interaction study with influenza vaccine has been conducted, studies of naturally acquired and experimental influenza indicate that treatment with oseltamivir does not impair normal humoral antibody response to infection.Prophylaxis given after contact with individuals who have influenza A or B respiratory tract illness should begin within 48 hours of exposure and continued for at least 10 days.

Usual Adult Dose for Avian Influenza:

Postexposure prophylaxis: 75 mg orally once or twice a day for 7 to 10 daysTreatment: Mild infection: 75 mg orally twice a day for 5 daysSevere infection: 150 mg twice a day for 7 to 10 daysLimited data are available.

Usual Pediatric Dose for Influenza:

Recommendations approved by FDA for emergency use in full-term infants:Weight-based dosing (preferred):Less than 1 year: 3 mg/kg orally twice a dayDosing by age (if weight not known):Birth through 2 months: 12 mg orally twice a day3 through 5 months: 20 mg orally twice a day6 through 11 months: 25 mg orally twice a day1 to 12 years:15 kg or less: 30 mg orally twice a day16 to 23 kg: 45 mg orally twice a day24 to 40 kg: 60 mg orally twice a day41 kg or more: 75 mg orally twice a day13 years or older: 75 mg orally twice a dayDuration: 5 days

Usual Pediatric Dose for Influenza Prophylaxis:

Recommendations approved by FDA for emergency use in full-term infants:Less than 3 months: Not recommended unless situation judged critical.Weight-based dosing (preferred):3 months to less than 1 year: 3 mg/kg orally once a dayDosing by age (if weight not known):3 through 5 months: 20 mg orally once a day6 through 11 months: 25 mg orally once a day1 to 12 years: 15 kg or less: 30 mg orally once a day16 to 23 kg: 45 mg orally once a day24 to 40 kg: 60 mg orally once a day41 kg or more: 75 mg orally once a day13 years or older: 75 mg orally once a dayOseltamivir should be started in anticipation of an outbreak and before or after a known exposure. For maximal effectiveness in an outbreak, the drug should be continued for the entire duration of influenza activity in the community, or at least during the period of peak influenza activity if cost is a concern. However, there are no data on the safety and efficacy of oseltamivir prophylaxis beyond 6 weeks.When used as an adjunct to influenza vaccination, chemoprophylaxis with antiviral agents may be given for approximately 2 weeks to provide interim protection until development of adequate antibody response. While no interaction study with influenza vaccine has been conducted, studies of naturally acquired and experimental influenza indicate that treatment with oseltamivir does not impair normal humoral antibody response to infection.Prophylaxis given after contact with individuals who have influenza A or B respiratory tract illness should begin within 48 hours of exposure and continued for at least 10 days.

Usual Pediatric Dose for Avian Influenza:

Mild infection:Children 1 to 12 years:15 kg or less: 30 mg orally twice a day16 to 23 kg: 45 mg orally twice a day24 to 40 kg: 60 mg orally twice a day41 kg or more: 75 mg orally twice a day13 years or older: 75 mg orally twice a dayLimited data are available.

What other drugs will affect oseltamivir?

There may be other drugs that can interact with oseltamivir. Tell your doctor about all the prescription and over-the-counter medications you use. This includes vitamins, minerals, herbal products, and drugs prescribed by other doctors. Do not start using a new medication without telling your doctor.

Where can I get more information?

  • Your pharmacist can provide more information about oseltamivir.
  • Remember, keep this and all other medicines out of the reach of children, never share your medicines with others, and use this medication only for the indication prescribed.
  • Every effort has been made to ensure that the information provided by Cerner Multum, Inc. ('Multum') is accurate, up-to-date, and complete, but no guarantee is made to that effect. Drug information contained herein may be time sensitive. Multum information has been compiled for use by healthcare practitioners and consumers in the United States and therefore Multum does not warrant that uses outside of the United States are appropriate, unless specifically indicated otherwise. Multum's drug information does not endorse drugs, diagnose patients or recommend therapy. Multum's drug information is an informational resource designed to assist licensed healthcare practitioners in caring for their patients and/or to serve consumers viewing this service as a supplement to, and not a substitute for, the expertise, skill, knowledge and judgment of healthcare practitioners. The absence of a warning for a given drug or drug combination in no way should be construed to indicate that the drug or drug combination is safe, effective or appropriate for any given patient. Multum does not assume any responsibility for any aspect of healthcare administered with the aid of information Multum provides. The information contained herein is not intended to cover all possible uses, directions, precautions, warnings, drug interactions, allergic reactions, or adverse effects. If you have questions about the drugs you are taking, check with your doctor, nurse or pharmacist.
Copyright 1996-2006 Cerner Multum, Inc. Version: 6.01. Revision Date: 11/11/2009 11:42:20 AM.
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