Oseltamivir (Oral Route)

Drug Information provided by: Micromedex

ARTICLE SECTIONS

US Brand Names

Tamiflu

Description

Oseltamivir belongs to the family of medicines called antivirals, which are used to treat infections caused by viruses. Oseltamivir is used in the treatment of the infection caused by the flu virus (influenza A and influenza B). Oseltamivir may reduce flu symptoms (weakness, headache, fever, cough, and sore throat) by 1 day. Oseltamivir is also used to prevent influenza infection if you have come into close contact with someone who has the flu .

If you receive the flu vaccine every year, continue to do so. Oseltamivir is not a substitute for your yearly flu shot .

Oseltamivir is available only with your doctor's prescription .

This product is available in the following dosage forms:

Powder for Suspension
Capsule

Before Using

In deciding to use a medicine, the risks of taking the medicine must be weighed against the good it will do. This is a decision you and your doctor will make. For this medicine, the following should be considered:

Allergies

Tell your doctor if you have ever had any unusual or allergic reaction to this medicine or any other medicines. Also tell your health care professional if you have any other types of allergies, such as to foods, dyes, preservatives, or animals. For non-prescription products, read the label or package ingredients carefully.

Pediatric

Appropriate studies have not been performed on the relationship of age to the effects of oseltamivir in children younger than 1 year of age. Safety and efficacy have not been established .

Geriatric

Appropriate studies performed to date have not demonstrated geriatrics-specific problems that would limit the usefulness of oseltamivir in the elderly .

Pregnancy

	Pregnancy Category	Explanation
All Trimesters	C	Animal studies have shown an adverse effect and there are no adequate studies in pregnant women OR no animal studies have been conducted and there are no adequate studies in pregnant women.

Breastfeeding

There are no adequate studies in women for determining infant risk when using this medication during breastfeeding. Weigh the potential benefits against the potential risks before taking this medication while breastfeeding.

Drug Interactions

Although certain medicines should not be used together at all, in other cases two different medicines may be used together even if an interaction might occur. In these cases, your doctor may want to change the dose, or other precautions may be necessary. Tell your healthcare professional if you are taking any other prescription or nonprescription (over-the-counter [OTC]) medicine.

Other Interactions

Certain medicines should not be used at or around the time of eating food or eating certain types of food since interactions may occur. Using alcohol or tobacco with certain medicines may also cause interactions to occur. Discuss with your healthcare professional the use of your medicine with food, alcohol, or tobacco.

Other Medical Problems

The presence of other medical problems may affect the use of this medicine. Make sure you tell your doctor if you have any other medical problems, especially:

Heart disease or
Illnesses caused by viruses other than influenza Type A or B or
Kidney disease or
Liver disease or
Lung disease or
Serious medical problems that may need admission to a hospital—Safety of this medicine for people with these conditions is not established .

Hereditary fructose intolerance—Use with caution. The powder form of this medicine contains sorbitol .

Proper Use

Talk to your doctor about the possibility of getting a flu shot if you have not had one yet. This medicine comes with a patient information form. Read this information carefully and talk to your doctor if you have any questions .

For patients taking oseltamivir for the treatment of flu: This medicine works best if taken within 2 days of having flu symptoms (weakness, headache, fever, cough, and sore throat). Oseltamivir capsules may be taken with meals or on an empty stomach. Taking oseltamivir with food may lessen the possibility of stomach upset. This medicine should be taken for 5 days. Continue taking this medicine for the full time of treatment even if you begin to feel better after a few days. This will help clear up your infection completely. If you stop taking this medicine too soon, your symptoms may return .

For patients taking oseltamivir for the prevention of flu after an exposure: The medicine should be taken within 2 days of being exposed to the flu. Oseltamivir capsules may be taken with meals or on an empty stomach. Taking oseltamivir with food may lessen the possibility of stomach upset. This medicine should be taken for at least 10 days .

For patients taking the oral suspension form of this medicine:

This medicine is to be taken only by mouth. Use the specially marked measuring device that comes with the medicine to measure each dose accurately. The average household teaspoon may not hold the right amount of liquid. If the measuring device is lost or damaged, contact your pharmacist or doctor to find out the appropriate dose .
Do not use the medicine after the expiration date on the label. The medicine may not work properly after that date. If you have any questions about this, check with your pharmacist .

Dosing

The dose of this medicine will be different for different patients. Follow your doctor's orders or the directions on the label. The following information includes only the average doses of this medicine. If your dose is different, do not change it unless your doctor tells you to do so.

The amount of medicine that you take depends on the strength of the medicine. Also, the number of doses you take each day, the time allowed between doses, and the length of time you take the medicine depend on the medical problem for which you are using the medicine.

For oral dosage forms (capsules and suspension):
- For treatment of the flu:
  - Adults and teenagers—75 milligrams (mg) two times a day for five days.
  - Children 1 year of age or older—Dose is based on body weight and must be determined by your doctor. It is usually between 30 and 75 mg two times a day for five days.
  - Children up to 1 year of age—Use and dose must be determined by your doctor .
- For prevention of the flu:
  - Adults and teenagers—75 milligrams (mg) once a day for at least ten days.
  - Children 1 year of age or older—Dose is based on body weight and must be determined by your doctor. It is usually between 30 and 75 mg once a day for ten days.
  - Children up to 1 year of age—Use and dose must be determined by your doctor .

Missed Dose

If you miss a dose of this medicine, take it as soon as possible. However, if it is almost time for your next dose, skip the missed dose and go back to your regular dosing schedule. Do not double doses.

Storage

Store the medicine in a closed container at room temperature, away from heat, moisture, and direct light. Keep from freezing.

Keep out of the reach of children.

Do not keep outdated medicine or medicine no longer needed.

Ask your healthcare professional how you should dispose of any medicine you do not use.

Precautions

Oseltamivir may cause some people, especially children and teenagers, to be agitated, irritable, or display other abnormal behaviors, which may result in injury. If you, your child, or your caregiver notice any of these side effects, tell your doctor or your child's doctor right away .

If your symptoms do not improve after you finish taking the medicine, or if they become worse, check with your doctor .

Side Effects

Along with its needed effects, a medicine may cause some unwanted effects. Although not all of these side effects may occur, if they do occur they may need medical attention.

Check with your doctor immediately if any of the following side effects occur:

Less common

Phlegm-producing cough
Wheezing

Rare

Abdominal or stomach cramps, or abdominal tenderness
Arm, back, or jaw pain
Bloating
Chest pain or discomfort
Chest tightness or heaviness
Diarrhea, watery and severe, which may also be bloody
Drooling
Facial swelling
Fast or irregular heartbeat
Fever
Hoarseness
Humerus fracture (broken forearm)
Increased thirst
Pain
Shortness of breath
Tender glands of the jaw and throat
Unusual tiredness or weakness
Unusual weight loss

Incidence not known

Blistering, peeling, or loosening of the skin
Chills
Convulsions (seizures)
Dark urine
Difficulty swallowing
Fainting
Fast, slow, or irregular heartbeat
General tiredness and weakness
Hives or welts
Itching
Itching, puffiness, or swelling of the eyelids or around the eyes, face, lips, or tongue
Joint or muscle pain
Light-colored stools
Loss of bladder control
Loss of consciousness
Muscle spasm or jerking of all extremities
Red skin lesions, often with a purple center
Red, irritated eyes
Red skin
Shortness of breath
Skin rash
Skin rash or itching over the entire body
Sore throat
Sores, ulcers, or white spots in the mouth or on the lips
Sudden loss of consciousness
Sweating
Swelling of the face or tongue
Tightness in the chest
Upper right abdominal pain
Weakness
Yellow eyes and skin

Some side effects may occur that usually do not need medical attention. These side effects may go away during treatment as your body adjusts to the medicine. Also, your health care professional may be able to tell you about ways to prevent or reduce some of these side effects. Check with your health care professional if any of the following side effects continue or are bothersome or if you have any questions about them:

More common