Tamiflu (generic name Oseltamivir) is used to treat some types of influenza infection (‘flu’) in adults and children (older than 1 year of age) who have had symptoms of the flu for no longer than 2 days. This medication is also used to prevent some types of flu in adults and children (older than 1 year of age) when they have spent time with someone who has the flu or when there is a flu outbreak.

Oseltamivir is in a class of medications called neuraminidase inhibitors. It works by stopping the spread of the flu virus in the body. Oseltamivir helps shorten the time you have flu symptoms such as a stuffy or runny nose, sore throat, cough, muscle or joint aches, tiredness, headache, fever, and chills. Oseltamivir will not prevent bacterial infections, which may occur as a complication of the flu.

How should this medicine be used?

Oseltamivir comes as a capsule and a suspension (liquid) to take by mouth. When oseltamivir is used to treat flu symptoms, it is usually taken two times a day (morning and evening) for 5 days. When oseltamivir is used to prevent flu, it is usually taken once a day for at least 10 days, or for up to 6 weeks during a community flu outbreak. Oseltamivir may be taken with or without food, but you may lessen the chance of getting an upset stomach by taking oseltamivir with food or milk. Follow the directions on your prescription label carefully, and ask your doctor or pharmacist to explain any part that you do not understand. Take oseltamivir exactly as directed. Do not take more or less of it or take it more often than prescribed by your doctor.

Sometimes doses of oseltamivir oral suspension are measured in milliliters (mL) and sometimes they are measured in milligrams (mg). This depends on the age of the person being treated and on whether the commercial suspension or a suspension that has been prepared by a pharmacist is being used. It is important to know whether your or your child’s dose should be measured in mL or mg and to use a measuring device that will measure the dose in the proper units. If you are using a suspension that was prepared by a pharmacist, the dose should be measured in mL. If you are using the commercial suspension to treat a person older than one year of age, the dose should be measured in mg. If you are using either product to treat a child under one year of age, the dose should be measured in mL. Before taking oseltamivir oral suspension, check to be sure that the instructions on the prescription label are given in the proper units as described above and that the measuring device that was provided is marked in the proper units. If you think that the directions on your prescription label are incorrect, that the measuring device you received is marked with the wrong units, or you have any questions about how to measure the medication, call your doctor or pharmacist. Never use a household teaspoon to measure doses of oseltamivir oral suspension.

If you are giving the commercial suspension to a child over one year of age, follow these steps to measure the dose using the syringe provided:

Shake the suspension well (for about 5 seconds) before each use to mix the medication evenly.

Open the bottle by pushing down on the cap and turning the cap at the same time.

Push the plunger of the measuring device completely down to the tip.

Insert the tip of the measuring device firmly into the opening on the top of the bottle.

Turn the bottle (with the measuring device attached) upside down.

Pull back on the plunger slowly until the amount of suspension prescribed by your doctor fills the measuring device to the appropriate marking (in milligrams [mg]). Some larger doses may need to be measured using the measuring device twice. If you are not sure how to correctly measure the dose your doctor has prescribed, ask your doctor or pharmacist.

Turn the bottle (with the measuring device attached) right-side up and slowly remove the measuring device.

Take oseltamivir directly into your mouth from the measuring device; do not mix with any other liquids.

Replace the cap on the bottle and close tightly.

Remove the plunger from the rest of the measuring device and rinse both parts under running tap water. Allow the parts to air dry before putting back together for the next use.

Call your doctor or pharmacist to find out how you should measure a dose of oseltamivir suspension if you do not have the measuring device that came with this medication.

If you have difficulty swallowing capsules, your doctor may tell you to open the capsule and mix the contents with a sweetened liquid. To prepare doses of oseltamivir for people who cannot swallow the capsules:

Hold the capsule over a small bowl and carefully pull open the capsule and empty all of the powder from the capsule into the bowl. If your doctor has instructed you to take more than one capsule for your dose, then open the correct number of capsules into the bowl.

Add a small amount of sweetened liquid, such as regular or sugar-free chocolate syrup, to the powder.

Stir the mixture.

Swallow the entire contents of this mixture right away.

Continue to take oseltamivir until you finish the prescription, even if you start to feel better. Do not stop taking oseltamivir without talking to your doctor. If you stop taking oseltamivir too soon or skip doses, your infection may not be fully treated, or you may not be protected from the flu.

If you feel worse or develop new symptoms while taking oseltamivir, or if your flu symptoms do not start to get better, call your doctor.

Ask your pharmacist or doctor for a copy of the manufacturer’s information for the patient.

Other uses for this medicine

Oseltamivir may be used to treat and prevent infections from avian (bird) influenza (a virus that usually infects birds but can also cause serious illness in humans). Oseltamivir also may be used to treat and prevent infections from influenza A (H1N1).

This medication may be prescribed for other uses; ask your doctor or pharmacist for more information.
What special precautions should I follow?

Before taking oseltamivir,

tell your doctor and pharmacist if you are allergic to oseltamivir or any other medications.

tell your doctor what prescription and nonprescription medications, vitamins, nutritional supplements and herbal products you are taking or plan to take. Be sure to mention any of the following: medications that affect the immune system such as azathioprine (Imuran); cyclosporine (Neoral, Sandimmune); cancer chemotherapy medications; methotrexate (Rheumatrex); sirolimus (Rapamune); oral steroids such as dexamethasone (Decadron, Dexone), methylprednisolone (Medrol), and prednisone (Deltasone); or tacrolimus (Prograf). Your doctor may need to change the doses of your medications or monitor you carefully for side effects.

tell your doctor if you have ever taken oseltamivir to treat or prevent the flu.

tell your doctor if you have any disease or condition that affects your immune system such as human immunodeficiency virus (HIV) or acquired immunodeficiency syndrome (AIDS) or if you have heart, liver, lung, or kidney disease.

tell your doctor if you are pregnant, plan to become pregnant, or are breast-feeding. If you become pregnant while taking oseltamivir, call your doctor.

you should know that people, especially children and teenagers, who have the flu may become confused, agitated, or anxious, and may behave strangely, have seizures or hallucinate (see things or hear voices that do not exist), or harm or kill themselves. You or your child may develop these symptoms whether or not you or your child uses oseltamivir, and the symptoms may begin shortly after starting treatment if you do use the medication. If your child has the flu, you should watch his or her behavior very carefully and call the doctor right away if he or she becomes confused or behaves abnormally. If you have the flu, you, your family, or your caregiver should call the doctor right away if you become confused, behave abnormally, or think about harming yourself. Be sure that your family or caregiver knows which symptoms may be serious so they can call the doctor if you are unable to seek treatment on your own.

ask your doctor if you should receive a flu vaccination each year. Oseltamivir does not take the place of a yearly flu vaccine. If you received or plan to receive the intranasal flu vaccine (FluMist; flu vaccine that is sprayed into the nose), you should tell your doctor before taking oseltamivir. Oseltamivir may make the intranasal flu vaccine less effective if it is taken up to 2 weeks after or up to 48 hours before the intranasal flu vaccine is given.

if you have fructose intolerance (an inherited condition in which the body lacks the protein needed to break down fructose, a fruit sugar, such as sorbitol), you should know that the oseltamivir suspension is sweetened with sorbitol. A 75 mg dose of oseltamivir suspension contains 2 grams of sorbitol, which is likely above the recommended maximum daily amount of sorbitol for someone with this condition. Tell your doctor if you have fructose intolerance.

What should I do if I forget a dose?

If you forget to take a dose, take it as soon as you remember it. If it is no longer than 2 hours before your next scheduled dose, skip the missed dose and continue your regular dosing schedule. If you miss several doses, call your doctor for directions. Do not take a double dose to make up for a missed one.

What side effects can this medication cause?

Oseltamivir may cause side effects. Tell your doctor if any of these symptoms are severe or do not go away:

nausea

vomiting

stomach pain

diarrhea

headache

Some side effects can be serious. If you experience any of these symptoms or those mentioned in the SPECIAL PRECAUTIONS section, call your doctor immediately:

rash, hives, or blisters on the skin

itching

swelling of the face or tongue

difficulty breathing or swallowing

hoarseness

changes in behavior

What storage conditions are needed for this medicine?

Keep this medication in the container it came in and out of reach of children. Store the capsules at room temperature and away from excess heat and moisture (not in the bathroom). Keep the suspension in the refrigerator. Do not freeze oseltamivir suspension. Throw away any unused suspension after 10 days. Throw away any medication that is outdated or no longer needed. Talk to your pharmacist about the proper disposal of your medication.
In case of emergency/overdose

In case of overdose, call hospital emergency.

Symptoms of overdose may include:

nausea

vomiting

What other information should I know?

Oseltamivir will not stop you from giving the flu to others. You should wash your hands frequently, and avoid practices such as sharing cups and utensils that can spread the virus to others.

Do not let anyone else take your medication. Your prescription is probably not refillable. If you still have symptoms of the flu after you finish taking oseltamivir, call your doctor.

It is important for you to keep a written list of all of the prescription and nonprescription (over-the-counter) medicines you are taking, as well as any products such as vitamins, minerals, or other dietary supplements. You should bring this list with you each time you visit a doctor or if you are admitted to a hospital. It is also important information to carry with you in case of emergencies.