Tamiflu (oseltamivir)
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.
If you have any of the conditions listed above, you may need a dose adjustment or special tests to safely take this medication.
Tamiflu is in pregnancy category C. This medication may be harmful to an unborn baby. Tell your doctor if you are pregnant or plan to become pregnant during treatment. 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.
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. Tell your doctor about any unusual or bothersome side effect.
What other drugs will affect oseltamivir?
There may be other 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.
