Oseltamivir: uses, dosing, side effects & brands
Oseltamivir is a neuraminidase inhibitor sold in the U.S. under one brand, for human influenza. Below: what the FDA label says, every product that contains it, what the pills look like, and its recall record.
Key facts
- Drug class
- Neuraminidase Inhibitor
- Treats (across its forms)
- Human Influenza
- Available as
- Capsule · Powder
- Sold as
- Tamiflu
- Prescription?
- Prescription only
- Generic available?
- Not in our catalog
- Half-life
- about 1 to 3 hours
- What the pharmacy pays
- about $0.15 per ml — not your price
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How oseltamivir is dosed
From the FDA label for Tamiflu (application NDA021087). Other oseltamivir products — different forms, different strengths — are dosed differently. Follow the label for the one you were prescribed.
Treatment of influenza Adults and adolescents (13 years and older): 75 mg twice daily for 5 days ( 2.2 ) Pediatric patients 1 to 12 years of age: Based on weight twice daily for 5 days ( 2.2 ) Pediatric patients 2 weeks to less than 1 year of age: 3mg/kg twice daily for 5 days ( 2.2 ) Renally impaired adult patients (creatinine clearance >30-60 mL/min): Reduce to 30 mg twice daily for 5 days ( 2.4 ) Renally impaired adult patients (creatinine clearance >10-30 mL/min): Reduce to 30 mg once daily for 5 days ( 2.4 ) ESRD patients on hemodialysis: Reduce to 30 mg immediately and then 30 mg after every hemodialysis cycle. Treatment duration not to exceed 5 days ( 2.4 ) ESRD patients on CAPD: Reduce to a single 30 mg dose immediately ( 2.4 ) Prophylaxis of influenza Adults and adolescents (13 years and older): 75 mg once daily for at least 10 days ( 2.3 ) - Community outbreak: 75 mg once daily for up to 6 weeks ( 2.3 ) Pediatric patients 1 to 12 years of age: Based on weight once daily for 10 days ( 2.3 ) - Community outbreak: Based on weight once daily for up to 6 weeks ( 2.3 ) Renally impaired adult patients (creatinine clearance >30-60 mL/min): Reduce to 30 mg once daily ( 2.4 ) Renally impaired adult patients (creatinine clearance >10-30 mL/min): Reduce to 30 mg once every other day ( 2.4 ) ESRD patients on hemodialysis: Reduce to 30 mg immediately and then 30 mg after alternate…
Oseltamivir side effects
The following serious adverse reactions are discussed below and elsewhere in the labeling: Serious skin and hypersensitivity reactions [see Warnings and Precautions (5.1) ] Neuropsychiatric events [see Warnings and Precautions (5.2) ] Most common adverse reactions (>1% and more common than with placebo): Treatment studies – Nausea, vomiting, headache. ( 6.1 ) Prophylaxis studies – Nausea, vomiting, headache, pain. ( 6.1 ) To report SUSPECTED ADVERSE REACTIONS, contact Genentech at 1-888-835-2555 or FDA at 1-800-FDA-1088 or www.fda.gov/medwatch 6.1 Clinical Trials Experience Because clinical trials are conducted under widely varying conditions, adverse reaction rates observed in the clinical trials of a drug cannot be directly compared to rates in the clinical trials of another drug and may not reflect the rates observed in practice. Adverse Reactions from Treatment and Prophylaxis Trials in Adult and Adolescent Subjects (13 years of age and older) The overall safety profile of TAMIFLU is based on data from 2,646 adult and adolescent subjects that received the recommended dosage of 75 mg orally twice daily for 5 days for treatment of influenza and 1,943 adult and adolescent subjects that received the recommended dosage of 75 mg orally once daily for up to 6 weeks for prophylaxis of influenza in clinical trials. The most common adverse reactions in the pooled treatment and…
Who shouldn’t take oseltamivir
TAMIFLU is contraindicated in patients with known serious hypersensitivity to oseltamivir or any component of the product. Severe allergic reactions have included anaphylaxis and serious skin reactions including toxic epidermal necrolysis, Stevens-Johnson Syndrome, and erythema multiforme [see Warnings and Precautions (5.1) ] . Patients with known serious hypersensitivity to oseltamivir or any of the components of TAMIFLU ( 4 )
Oseltamivir drug interactions
Live attenuated influenza vaccine (LAIV), intranasal: Avoid administration of LAIV within 2 weeks before or 48 hours after TAMIFLU use, unless medically indicated. ( 7 ) 7.1 Influenza Vaccines Live Attenuated Influenza Vaccine The concurrent use of TAMIFLU with live attenuated influenza vaccine (LAIV) intranasal has not been evaluated. However, because of the potential for TAMIFLU to inhibit replication of live vaccine virus and possibly reduce the efficacy of LAIV, avoid administration of LAIV within 2 weeks before or 48 hours after TAMIFLU administration, unless medically indicated. Inactivated Influenza Vaccine Inactivated influenza vaccine can be administered at any time relative to use of TAMIFLU. 7.2 Drugs Without Clinically Significant Drug Interaction with TAMIFLU No dose adjustments are needed for either oseltamivir or the concomitant drug when coadministering oseltamivir with amoxicillin, acetaminophen, aspirin, cimetidine, antacids (magnesium and aluminum hydroxides and calcium carbonates), rimantadine, amantadine, or warfarin [see Clinical Pharmacology (12.3) ] .
Every oseltamivir product we track (1)
Same active ingredient — different manufacturer, form, price and FDA recall record. That last one is what our independent score measures.
Only one: Tamiflu.
What oseltamivir pills look like
Imprint codes, colour and shape from the FDA’s labelling data. Match the imprint on your pill — or search any imprint.
Oseltamivir recalls
From the FDA Enforcement database. A recall covers specific lots — not the drug as a whole.
Oseltamivir and breastfeeding
From LactMed, the US National Library of Medicine’s Drugs and Lactation Database — quoted, not rewritten.
Full LactMed record for oseltamivir: levels in milk, effects in breastfed infants, and the drugs it would consider insteadLimited data indicate that oseltamivir and its active metabolite are poorly excreted into breastmilk. Maternal dosages of 150 mg daily produce low levels in milk and would not be expected to cause any adverse effects in breastfed infants. Infants over 2 weeks of age can receive oseltamivir directly in doses much larger than those in breastmilk.
National Institute of Child Health and Human Development, record revised February 15, 2024. LactMed states its information is not a substitute for professional judgement.
What people report to the FDA about oseltamivir
The FDA Adverse Event Reporting System (FAERS) collects reports from patients and clinicians. It holds 1,930 reports naming oseltamivir, and the FDA flagged 63% of those reports as serious. The effects reported most often — leaving out reports about overdose, misuse or the condition being treated, which dominate the raw list for common medicines:
- vomiting307 reports
- nausea274 reports
- abdominal pain178 reports
- abdominal distension164 reports
- constipation162 reports
- ascites157 reports
- appendicitis156 reports
- appendicolith153 reports
Read these as a signal, not a rate. A report does not mean oseltamivir caused the effect — anyone can file one, and many describe people taking several medicines for several conditions. Crucially there is no denominator: FAERS does not record how many people took the drug, so these counts cannot be turned into “X% of patients” — a bigger number often just means a more widely used or more talked-about drug. Duplicates exist, and publicity drives reporting. For what is actually established, read the FDA label section above.
Source: openFDA drug/event (FAERS), retrieved July 25, 2026.
How long oseltamivir stays in your system
The elimination half-life of oseltamivir is about 1 to 3 hours. Oseltamivir itself is a prodrug and clears fast — the label reports a plasma half-life of 1 to 3 hours in most people. What actually fights the flu is its active metabolite, oseltamivir carboxylate, which lasts far longer: a half-life of 6 to 10 hours. Less than 5% of an oral dose stays in the blood as oseltamivir; at least 75% arrives as the carboxylate, which is cleared unchanged by the kidneys. Kidney function is what matters most: exposure to the active metabolite rises as kidney function falls (the label gives reduced dosing for CrCl 30-60, 10-30 mL/min, and hemodialysis; oseltamivir has not been studied in end-stage kidney disease off dialysis). In adults 65-78, half-lives were similar to young adults even though metabolite exposure ran 25-35% higher, and no dose change is needed. Mild-to-moderate liver impairment did not change metabolite exposure. There is no extended-release form — only capsules and oral suspension.
TAMIFLU (oseltamivir phosphate) prescribing information, Genentech, Inc. — Section 12.3 Pharmacokinetics ↗Half-life is how long the body takes to clear half a dose. It is not the same as how long a drug test can detect it, and it varies with age, kidney and liver function.
Related calculators
Frequently asked questions
What is oseltamivir?
TAMIFLU (oseltamivir phosphate), an influenza neuraminidase inhibitor (NAI), is available as: Capsules containing 30 mg, 45 mg, or 75 mg of oseltamivir for oral use, in the form of oseltamivir phosphate, and A powder for oral suspension, which when constituted with water as directed contains 6 mg per mL oseltamivir base. In addition to the active ingredient, each capsule contains croscarmellose sodium, povidone K30, pregelatinized starch, sodium stearyl fumarate and talc. The 30 mg capsule shell contains gelatin, red iron oxide, titanium dioxide, and yellow iron oxide. The 45 mg capsule shell contains black iron oxide, gelatin, and titanium dioxide. The 75 mg capsule shell contains black iron oxide, gelatin, red iron oxide, titanium dioxide, and yellow iron oxide. Each capsule is printed with blue ink, which includes FD&C Blue No. 2 as the colorant. In addition to the active ingredient, the powder for oral suspension contains monosodium citrate, saccharin sodium, sodium benzoate, sorbitol, titanium dioxide, tutti-frutti flavoring, and xanthan gum.
What kind of drug is oseltamivir?
The FDA classifies oseltamivir as a neuraminidase inhibitor. If you are checking whether it is safe to combine with something else, the class is what matters — two drugs from the same class usually should not be stacked.
How long does oseltamivir stay in your system?
The elimination half-life of oseltamivir is about 1 to 3 hours — that is how long the body takes to clear half of a dose. Oseltamivir itself is a prodrug and clears fast — the label reports a plasma half-life of 1 to 3 hours in most people. What actually fights the flu is its active metabolite, oseltamivir carboxylate, which lasts far longer: a half-life of 6 to 10 hours. Less than 5% of an oral dose stays in the blood as oseltamivir; at least 75% arrives as the carboxylate, which is cleared unchanged by the kidneys. Kidney function is what matters most: exposure to the active metabolite rises as kidney function falls (the label gives reduced dosing for CrCl 30-60, 10-30 mL/min, and hemodialysis; oseltamivir has not been studied in end-stage kidney disease off dialysis). In adults 65-78, half-lives were similar to young adults even though metabolite exposure ran 25-35% higher, and no dose change is needed. Mild-to-moderate liver impairment did not change metabolite exposure. There is no extended-release form — only capsules and oral suspension. Half-life is not the same as how long a drug test can detect the drug, and it varies with age, kidney and liver function.
Can you take oseltamivir with other medicines?
It depends on the medicine. We check it against the FDA labels rather than guessing: our interaction checker searches each drug's own label for the other and quotes what it says, naming the section it came from. Run oseltamivir against whatever else you take — and remember that a label not naming a drug is not the same as that combination being safe.
What forms does oseltamivir come in?
Across the brands we track, oseltamivir is currently marketed as capsule and powder, per the FDA's National Drug Code Directory. Each form is dosed differently — follow the label for the exact product you were prescribed.
Is there a generic oseltamivir?
We do not currently list a generic-labelled oseltamivir product. That does not always mean none exists — it means none appears under a generic name in the FDA data we track. Ask your pharmacist.
Has oseltamivir been recalled?
The FDA's Enforcement database lists 1 recall record whose product description mentions oseltamivir. The most recent: Oseltamivir Phosphate for Oral Suspension 6mg/ml (Feb 13, 2024). A recall applies to specific lots, not to the drug as a whole — check the record for the affected lot numbers.
Cite this page
- APA
- pharmaranks. (2026, July 24). Oseltamivir: uses, dosing, side effects & brands. https://pharmaranks.com/drugs/oseltamivir
- MLA
- “Oseltamivir: uses, dosing, side effects & brands.” pharmaranks, 24 July 2026, https://pharmaranks.com/drugs/oseltamivir.
We summarise public FDA and NIH sources — for a clinical claim, cite the primary source we link to as well.
Sources: FDA openFDA drug label, National Drug Code Directory, and Enforcement (recall) database. This page reproduces public FDA data and is not medical advice. Dosing is set by your prescriber.
Read the full FDA label for oseltamivir on DailyMed (NIH) ↗.