GENERIC NAME: Oseltamivir

COMMON BRAND: Tamiflu

Oseltamivir is an oral prescription antiviral drug belongs to the class of medications known as a neuraminidase inhibitor. It works by inhibiting (neuraminidase of influenza virus) the spread of the flu virus in the body. Oseltamivir sold under the brand name “Tamiflu” used to treat and prevent influenza A and influenza B which is also known as “Swine Flu“. The most common flu virus in human is influenza A – H1N1 virus. It is available with brand name version and the generic name version. The generic drug usually cost less.

What is Oseltamivir (Tamiflu) used for?

Treatment of Influenza (flu):

Oseltamivir is used to treat uncomplicated influenza infection in adults and children one year and above who have had symptoms of flu (such as stuffy nose, cough, sore throat, fever/chills, aches, tiredness) not more than two days.

Prevention of Influenza (flu):

Oseltamivir is also used to prevent influenza in adults and children above one year in case of exposure to an infected person with flu or if there is an outbreak.

How to use Oseltamivir (Tamiflu)?

Before you start your treatment with oseltamivir, and each time you get a refill, read the patient information guideline if available from your pharmacist.

Take oseltamivir exactly as instructed by your doctor. Do not alter your dose or take it more frequently than prescribed, as there is a risk of developing resistance.

Take oseltamivir orally with or without food but is less likely to cause stomach upset. Take this medication with the first sign of flu or immediately after you have been exposed to the flu. This medicine works best if you take within two days of either of these cases.

If oseltamivir is used to treat flu symptoms, it is usually taken twice a day (morning and evening) for five days. If it is used to prevent flu, it is usually taken once per day for about ten days.

This medication is available in capsule and liquid suspension form. If you are using suspension shake the bottle before use and measure the dose with the help of measuring spoon, do not use a household spoon for measuring the drug.

Seek advice from your doctor if your symptoms get worse or new symptoms appears while taking this drug.

What are the side effects of taking Oseltamivir (Tamiflu)?

The common side effects observed with the use of this drug like nausea, stomach pain, diarrhea, headache, and vomiting. If these effects continue or get worse, notify your doctor or pharmacist promptly.

Hallucination, delirium, abnormal behavior and self-injury have been noticed in patients with influenza who were receiving oseltamivir. This effects may be more likely in children. Tell your doctor right away if you see any of the above symptoms.

A severe hypersensitivity reaction may occur with use of this drug. However, get emergency medical help right away if you notice any symptoms of a severe hypersensitivity reaction, such as rash, itching/swelling (especially of the face/tongue/throat), severe dizziness, shortness of breath.

This is not a complete record of possible side effects. If you see other effects not listed above, contact your doctor or pharmacist promptly.

What are the precautions while using Oseltamivir (Tamiflu)?

Notify your doctor or pharmacist if you are allergic to this medicine before starting the treatment; or if you have some other allergies. The product containing oseltamivir may also include some other inactive ingredients that may cause allergic reactions or other illness. Ask your pharmacist regarding further information about this medicine.

This medicine may cause anaphylaxis (a type of allergic reaction which may be fatal). Seek medical assistance immediately if you have a rash, itching, breathlessness, hoarseness, trouble swallowing, or any swelling of your face/mouth/hands while you or your child are using this medicine.

In children and teenagers, this medication may cause display of abnormal behaviors like agitation and irritability, which may result in injury. If your child displays any of these effects, consult the doctor at the soonest. These effects can also be noticed in adults using this medication.

Notify your doctor or pharmacist about your medical history before the commencing the treatment with this medicine, especially if you have any kidney disease (including dialysis treatment).

This medication must be used only when clearly needed in pregnancy. Ask your doctor/pharmacist regarding the risks and benefits of this drug.

This medication may cross into breast milk. The effects of this drug are unknown on a nursing infant. Consult your doctor before breastfeeding.

What are the drug interactions of Oseltamivir (Tamiflu)?

Drug interactions may alter the efficacy of your medications or increase your risk of severe side effects. This record does not contain all the potential drug interactions. Keep a record of all the products you may be using (such as prescription, nonprescription drugs and herbal products) and discuss with your doctor and pharmacist. Do not start, stop, or alter the dosage of any medicines without your doctor’s consent.

Oseltamivir is known to interact with ampicillin, colchicine, probenecid, entecavir, probenecid, influenza virus vaccine (live H1N1), influenza virus vaccine-live trivalent (nasal spray), methotrexate, pemetrexed, warfarin.

Notify your doctor if you have received any nasal flu vaccine within 2 weeks before the commencement of the treatment with this medication. This medication may compromise your protection from the nasal flu vaccine against flu. Wait at least 2 days after the completion of the treatment with this medication before receiving the nasal flu vaccine.

WARNINGS:

Severe Skin/Hypersensitivity Reactions:

Cases of anaphylaxis (severe allergic reaction can lead to anaphylactic shock) and severe skin reactions including toxic epidermal necrolysis, Stevens-Johnson Syndrome (allergic reaction of face/tongue/throat with breathlessness) and erythema multiforme have been reported with Oseltamivir. This drug is not prescribed to people with any severe known hypersensitivity.

Neuropsychiatric Events:

Neuropsychiatric symptoms like delirium and abnormal behaviour have been noticed in patients with influenza who were receiving this drug. Regularly monitor patients taking oseltamivir for signs of unusual behaviour. Discontinue this drug seek immediate medical attention if neuropsychiatric symptoms occur.

Bacterial Infections:

Serious bacterial infections may occur with similar symptoms like influenza or may overlap with or occur as complications during the treatment of flu. Oseltamivir does not help to prevent such complications.

What are the forms and strengths of Oseltamivir (Tamiflu)?

Form: Capsule
Strengths: 30mg, 45mg, 75mg

Form: Powder for oral suspension
Strengths: 6mg/mL

What is the dosage of Oseltamivir (Tamiflu)?

For Treatment of Influenza A and B:

Adult (18 and above):

Regular dose: Take 75mg orally twice a day for five days.

Pediatric:

Children (0 to 2 weeks):

This drug is not recommended in this age group as safety and efficacy has not been established.

Children (2 weeks to 1 year):

Regular dose: Take 3mg/kg orally twice a day for 5 days.

Children (1 year and above): Dosage is based on weight in this age group.

Children (below 15kg): 30mg orally twice a day for 5 days
Children (15-23kg): 45mg orally twice a day for 5 days
Children (23-40kg): 60mg orally twice a day for 5 days
Children (Above 40kg): 75mg orally twice a day for 5 days

Dosing considerations: Take this drug for acute, uncomplicated flu infection in patients having flu symptoms no more than 48 hours.

For prevention of Influenza A and B:

Adult (18 and above):

Regular dose: Take 75mg orally once a day for 10 days.

Pediatric:

Children (below 1 year): 

Safety and efficacy of the drug have not been established for prevention in this age group.

Children (1 year and above): Dosage is based on weight in this age group.

Children (below 15kg): 30mg orally twice a day for 10 days
Children (15-23kg): 45mg orally twice a day for 10 days
Children (23-40kg): 60mg orally twice a day for 10 days
Children (40kg and above): 75mg orally twice a day for 10 days

Dosing considerations:

Treatment should start within 48 hours of exposure.
For community outbreak, may administer for up to 6 weeks

For Treatment of Swine Flu ( H1N1 Influenza A) (Off-label):

Adult (18 and above):

Regular dose: Take 75mg orally twice a day for 5 days.

Acute illness:

Pediatric:

Children (below 1 year):

Children (below 3 months): 12mg orally twice a day for 5 days.
Children (3-5 months): 20mg orally twice a day for 5 days.
Children (6-11 months): 25mg orally twice a day for 5 days.

Children (1 year and above): Dosage is based on weight in this age group.

Children (Below 15kg): 30mg orally twice a day for 5 days.
Children (15-23kg): 45mg orally twice a day for 5 days.
Children (23-40kg): 60mg orally twice a day for 5 days.
Children (40kg and above): Administered as in adults.

Dosing considerations:

Start within 48 hours of onset influenza symptom.

For Prevention of Swine Flu ( H1N1 Influenza A) (Off-label):

Adult (18 and above):

Regular dose: Take 75mg orally once a day.

Pediatric:

Children (below 1 year):

Children (below 3 months): Data limited; not recommended unless situation judged critically.
Children (3-5 months): 20mg orally once a day for 10 days.
Children (6-11 months): 25mg orally once a day for 10 days.

Children (1 year and above): Dosage is based on weight in this age group.

Children (below 15kg): 30mg orally once a day for 10 days.
Children (15-23kg): 45mg orally once a day for 10 days.
Children (23-40kg): 60mg orally once a day for 10 days.
Children (40kg and above): Administered as in adults.

Dosing considerations:

Post-exposure prevention: Initiate within seven days of exposure and continue for at least ten days.

Pre-exposure Prevention (community outbreak): Start during the potential exposure period and continue for 10 days after last known exposure.

Most common questions asked about Oseltamivir (Tamiflu) / Q&A’s:

How long are you contagious with the flu after taking Oseltamivir (Tamiflu)?

You are contagious from the day1, even before you see any symptoms, until 5 days to a week after you start feeling the sickness. You stay that way for 5 to 7 days after you start feeling sick. Children may spread the virus for even longer until all of their symptoms fade.

Does Oseltamivir (Tamiflu) prevent pneumonia?

No, Tamiflu is an antiviral drug and used for the treatment of swine flu which is a viral infection and not the bacterial infection. However, antibiotics can be used for the treatment of some severe complications of swine flu that may develop such as pneumonia.

Disclaimer

TheMedPharma has made every effort to make sure that all the information is factually correct, comprehensive, and up-to-date. However, this website should not be considered as a substitute for the advice, knowledge and expertise of a licensed healthcare professional. You should always consult your doctor or licensed health care professional before taking any medication. The drug information contained herein is subjected to changes if required. The lack of warnings or other information for a given drug does not mean that the drug or its combination is safe, effective or appropriate for use in all patients.