Tamiflu dosage: how much to take, how often and for how many days

How much Tamiflu should an adult take?

Adults and teens 13 and older take 75 mg of Tamiflu twice a day for 5 days, usually one capsule in the morning and one in the evening. Starting within 48 hours of your first symptoms gives the best chance of a shorter, milder illness.

• Prevention after close contact: 75 mg once a day for 7 days after the last known exposure.
• Children 1 to 12 years: The dose is based on weight and given twice a day for 5 days. It ranges from 30 mg for children 15 kg or less up to 75 mg for children over 40 kg.
• Infants 2 weeks to under 1 year: The label dose is 3 mg/kg per dose, twice a day for 5 days. That equals 0.5 mL/kg of the 6 mg/mL oral suspension. The American Academy of Pediatrics recommends 3.5 mg/kg twice daily for infants 9 to 11 months old. A pediatrician sets the exact amount.
• After the 48-hour mark: People at higher risk of flu complications, and anyone with severe or worsening illness, should still be treated even if more than 48 hours have passed.

Tamiflu 75 mg: how many days and how often

Twice daily means about 12 hours apart, for the full 5 days. This dosing is based on clinical trials and FDA labeling.

Tamiflu dosage chart by age and weight

Tamiflu preventative dose for adults

Tamiflu can also be used to prevent flu in people exposed to the virus but not yet symptomatic. The typical dose for adults is 75 mg once daily for 7 days after the last known exposure, or longer during a community outbreak.

Is Tamiflu 150 mg ever used?

Yes, but 150 mg is usually the total amount you take in one day, not a single dose. The standard adult treatment is one 75 mg capsule twice daily for 5 days, which adds up to 150 mg per day. Taking two capsules at once is not part of that regimen.

A higher dose, such as 150 mg twice daily, is a separate clinical decision:

• Who it is considered for: Some experts have recommended 150 mg twice daily for adults with normal kidney function who have weakened immune systems or are severely ill in the hospital. Higher-dose oseltamivir is not routinely recommended, however, because available evidence has not shown additional clinical benefit over standard dosing.
• What the evidence shows: Standard doses appear to reach therapeutic blood levels even in critically ill adults.
• Body weight: Drug exposure is similar in people with and without obesity at both 75 mg and 150 mg twice daily, so a higher dose is not needed for size alone.

Do not increase your dose on your own. Extra Tamiflu can worsen nausea and vomiting, and adults with reduced kidney function may need a lower dose, not a higher one. If your symptoms are severe or you have a weakened immune system, call your prescriber, who can decide whether anything beyond the standard dose is appropriate.

Tips for taking Tamiflu

Tamiflu, known generically as oseltamivir, is a commonly prescribed antiviral medication for influenza. It works by blocking the virus from spreading within your body, helping to reduce symptoms and shorten the duration of the illness.

• Take Tamiflu with food to reduce stomach upset.
• Complete the full course even if you feel better early.
• Store Tamiflu suspension in the refrigerator and shake well before use.
• Call your prescriber if you have unusual side effects.

What is the typical Tamiflu dose for children?

Children’s treatment dosing depends heavily on weight:

• 15 kg or less: 30 mg twice daily
• Over 15 to 23 kg: 45 mg twice daily
• Over 23 to 40 kg: 60 mg twice daily
• Over 40 kg: Adult dosing applies

For children 1 to 12 years, the typical Tamiflu dose for prevention is a weight-based amount, the same amount used for treatment, but given once daily instead of twice daily. If your child cannot swallow capsules, the oral suspension (a liquid form of the medicine) is often used instead. Our guide to Tamiflu for kids covers safety and side effects.

Missed a Tamiflu dose?

If you miss a dose, take it as soon as you remember, unless it is almost time for your next dose. Our guide to a missed Tamiflu dose covers what to do in more detail. Do not double up to make up for the missed dose, as this can increase the risk of side effects. Keeping to a consistent schedule helps keep the medication effective.

How to adjust your Tamiflu dose for certain medical conditions

Kidney impairment

People with reduced kidney function may require dose adjustments because Tamiflu is cleared by the kidneys. Lower doses or extended dosing intervals may be necessary to avoid accumulation and toxicity. Your prescriber will set the right dose for your kidney function.

Label doses for adults, based on creatinine clearance (a measure of how well your kidneys filter blood):

• Treatment, 30 to 60 mL/min: 30 mg twice daily for 5 days
• Treatment, 10 to 30 mL/min: 30 mg once daily for 5 days
• Treatment, hemodialysis: 30 mg right away, then 30 mg after every dialysis cycle, for no more than 5 days
• Treatment, CAPD (a form of home dialysis): a single 30 mg dose right away
• Prevention, 30 to 60 mL/min: 30 mg once daily
• Prevention, 10 to 30 mL/min: 30 mg once every other day
• Prevention, hemodialysis: 30 mg right away, then 30 mg after every other dialysis cycle
• Prevention, CAPD: 30 mg right away, then 30 mg once weekly

Tamiflu is not recommended for people with end-stage kidney disease who are not on dialysis. For a full breakdown of oseltamivir renal dosing and generic forms, see the separate oseltamivir guide.

Pregnancy and breastfeeding

During pregnancy, Tamiflu is the preferred antiviral for flu treatment, and it is generally considered safe while breastfeeding, but a doctor should confirm your dose. Treatment works best when you start within 48 hours of your first symptoms, so call your prescriber early instead of waiting to see if you improve. Personalized advice helps balance the benefits and risks for your situation and health history.

Tamiflu overdose and warnings

Taking more than the prescribed dose of Tamiflu can cause nausea, vomiting, and other side effects. In case of overdose, seek medical attention immediately.

Our Tamiflu side effects guide covers the full list of possible side effects and what to do about them. Serious allergic reactions are rare but require urgent care.

Frequently Asked Questions

Can I take Tamiflu if I miss the 48-hour window after flu symptoms start?

Tamiflu is most effective when started within 48 hours of symptom onset. However, people at high risk for complications, or with severe or worsening illness, should still be treated even after this window.

Is it safe to take Tamiflu every flu season?

Yes, Tamiflu can be used each flu season if needed for treatment or prevention. Ask your doctor whether it's right for you each time.

Can children under 1 year take Tamiflu?

Tamiflu is approved to treat flu in infants as young as 2 weeks old (prevention is approved from age 1), but a pediatrician should set the dose.

What should I do if I experience side effects from Tamiflu?

Mild side effects like nausea often improve with food. If side effects are severe, contact a doctor right away. If they don't go away, call your prescriber.

How does Tamiflu interact with other medications?

Tamiflu has a few drug interactions, but always inform your doctor about all medications and supplements you are taking to avoid potential issues.

The Bottom Line

Adults and teens 13 and older usually take 75 mg of Tamiflu twice a day for 5 days to treat the flu, ideally starting within 48 hours of symptoms. Prevention after close contact uses 75 mg once a day for 7 days after the last known exposure. Kidney problems may call for a lower dose, so tell your prescriber. Do not change your dose on your own.