Generic Name: oseltamivir (os el TAM ih veer)
Brand Name: 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 influenza in people 2 weeks of age and older who have had flu symptoms for 2 days or less. Oseltamivir may also be given to prevent influenza in people who are at least 1 year old, who may be exposed but do not yet have symptoms. Oseltamivir will not treat the common cold.
It is dangerous to purchase oseltamivir on the Internet or from vendors outside of the United States. Medications distributed from Internet sales may contain dangerous ingredients, or may not be distributed by a licensed pharmacy. Samples of "Tamiflu" purchased on the Internet have been found to contain cloxacillin, a type of antibiotic that can have dangerous side effects in people who are allergic to penicillin. For more information, contact the U.S. Food and Drug Administration (FDA) or visit www.fda.gov/buyonlineguide.
Oseltamivir may also be used for purposes not listed in this medication guide.
What is the most important information I should know about oseltamivir?
Follow all directions on your medicine label and package. Tell each of your healthcare providers about all your medical conditions, allergies, and all medicines you use.
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 oseltamivir if you are allergic to it.
To make sure oseltamivir is safe for you, tell your doctor if you have:
heart disease or chronic lung disease;
a condition causing swelling or disorder of the brain;
weak immune system (caused by disease or by using certain medicine);
hereditary fructose intolerance; or
if you have used a nasal flu vaccine (FluMist) within the past 2 weeks.
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. Tell your doctor if you are pregnant. Your doctor will decide whether you should receive oseltamivir.
It is not known whether oseltamivir passes into breast milk or if it could harm a nursing baby. Tell your doctor if you are breast-feeding a baby.
Do not use this medication to prevent influenza in a child younger than 1 year old. Do not use this medication to treat influenza in a child younger than 2 weeks old.
How should I take oseltamivir?
Follow all directions on your prescription label. Do not take this medicine in larger or smaller amounts or for longer than recommended.
Start taking oseltamivir as soon as possible after 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. Measure the liquid with a special dose-measuring spoon or medicine cup. If you do not have a dose-measuring device, ask your pharmacist for one.
You may open the oseltamivir capsule and sprinkle the medicine into a sweet liquid (corn syrup, chocolate syrup, brown sugar dissolved in water) to make swallowing easier. Swallow the mixture right away without chewing. Do not save for later use. Ask your doctor or pharmacist before using this method to prepare an oseltamivir dose for a child who is younger than 13 years old or weighs less than 88 pounds.
Oseltamivir may be taken with food or milk if it upsets your stomach.
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 17 days.
The liquid may also be stored at cool room temperature for up to 10 days
What happens if I miss a dose?
Take the missed dose as soon as you remember. Skip the missed dose if your next dose is less than 2 hours away. Do not take extra medicine to make up the missed dose.
What happens if I overdose?
Seek emergency medical attention or call the Poison Help line at 1-800-222-1222.
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
Get emergency medical help if you have any of these signs of an allergic reaction:
chest pain or tightness, difficult breathing;
fever, sore throat, swelling in your face or tongue, burning in your eyes; or
hives, skin pain, followed by a red or purple skin rash that spreads (especially in the face or upper body) and causes blistering and peeling.
Some people using oseltamivir have had rare side effects of sudden confusion, shaking, problems with speech, hallucinations (hearing or seeing things that are not there), or seizure (convulsions). These symptoms have occurred most often in children, but it is not known whether oseltamivir was the exact cause. Anyone using oseltamivir should be watched closely for signs of confusion or unusual behavior, especially a child.
Common side effects may include:
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.
See also: Side effects (in more detail)
What other drugs will affect oseltamivir?
Other drugs may interact with oseltamivir, including prescription and over-the-counter medicines, vitamins, and herbal products. Tell each of your health care providers about all medicines you use now and any medicine you start or stop using.
More about Tamiflu (oseltamivir)
Related treatment guides
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.
- Disclaimer: 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 1996-2012 Cerner Multum, Inc. Version: 11.01.
Date modified: January 10, 2017
Last reviewed: July 21, 2016