Reported Reactions

Drugs › Neuraminidase inhibitor

Generic name

Oseltamivir: adverse event reports filed with FDA

3,897 reports list it as a suspect or interacting product, 2004–2026. Class: Neuraminidase inhibitor. Also reported as Oseltamivir 75mg, Oseltamivir 75mg Capsules.

3,897
reports as suspect product
0% of all reports · about 175 a year
211
reports, 12 months to June 2026
666 in the 12 months before
72.8%
marked serious by the reporter
60.6% across the class
15.1%
record death among outcomes, as reported
590 reports · not verified by FDA

3,897 adverse event reports received by FDA list oseltamivir, a generic name as a suspect or interacting product, from April 2004 to June 2026. A further 2,445 reports list it only as a concomitant medication, and those are not counted in the figures on this page.

In the 12 months to June 2026, 211 reports listed it, down 68% from 666 in the 12 months before. FDA releases FAERS data quarterly, so the newest months are incomplete and grow in later releases. Over its reporting history that is about 175 reports a year and 0% of the 20,646,523 reports in the database, and 19.2% of the reports for the neuraminidase inhibitor class. How many people take it is not in the data, so a count is not a rate of occurrence.

The reactions recorded most often are off label use (31%), no adverse event (13.5%) and drug ineffective (9.9%). A report can list several reactions, so shares add to more than 100%; 626 different terms appear across these reports. Off label use is recorded in 31% of these reports, a larger share than in the median neuraminidase inhibitor drug (11%).

72.8% of the reports are marked serious by the reporter (60.6% across the class); 15.1% record death among the outcomes and 26.7% record hospitalisation, as reported. 52.9% of the reports came from other health professionals, and the largest patient age group is 18 to 44 (21.2%). FDA states that "a causal relationship cannot be established between product and reactions listed in a report" and that for any given report "there is no certainty that a suspected drug caused the event."

Reports by month, five years

0222443Jul 2021: 21Aug 2021: 43Sep 2021: 64Oct 2021: 28Nov 2021: 49Dec 2021: 492022Jan 2022: 19Feb 2022: 18Mar 2022: 16Apr 2022: 17May 2022: 14Jun 2022: 25Jul 2022: 16Aug 2022: 5Sep 2022: 24Oct 2022: 13Nov 2022: 32Dec 2022: 1452023Jan 2023: 10Feb 2023: 13Mar 2023: 3Apr 2023: 12May 2023: 8Jun 2023: 10Jul 2023: 23Aug 2023: 8Sep 2023: 5Oct 2023: 15Nov 2023: 14Dec 2023: 142024Jan 2024: 14Feb 2024: 24Mar 2024: 14Apr 2024: 4May 2024: 4Jun 2024: 30Jul 2024: 22Aug 2024: 7Sep 2024: 443Oct 2024: 29Nov 2024: 3Dec 2024: 122025Jan 2025: 29Feb 2025: 45Mar 2025: 25Apr 2025: 24May 2025: 13Jun 2025: 14Jul 2025: 14Aug 2025: 6Sep 2025: 16Oct 2025: 7Nov 2025: 24Dec 2025: 452026Jan 2026: 27Feb 2026: 25Mar 2026: 10Apr 2026: 8May 2026: 8Jun 2026: 21

Reports by the month FDA received them. FDA releases FAERS data quarterly, so the newest months are incomplete and grow in later releases.

By year received

03156302004: 320042005: 72006: 42007: 720072008: 152009: 2112010: 11220102011: 1222012: 482013: 4420132014: 232015: 522016: 6820162017: 832018: 1782019: 25220192020: 5922021: 6302022: 34420222023: 1352024: 6062025: 26220252026: 99

2026 covers reports received through June 2026 only.

Reactions recorded in the reports

share of Oseltamivir reports recording the termmedian drug in neuraminidase inhibitor

  1. Off label useused for a purpose or in a way not on the label31%1,210
  2. No adverse eventno adverse event was reported13.5%528
  3. Drug ineffectivethe medicine did not work as expected9.9%385
  4. Foetal exposure during pregnancythe unborn baby was exposed to the medicine5.1%197
  5. Condition aggravatedthe condition being treated got worse4.2%165
  6. Maternal exposure during pregnancythe mother took the medicine during pregnancy4.2%165
  7. Vomitingbeing sick4%154
  8. Neutropenialow neutrophils, a type of white blood cell3.8%149
  9. Product use in unapproved indicationused for a purpose not on the label3.3%128
  10. Nauseafeeling sick3.3%127
  11. Pneumonialung infection2.8%109
  12. Bradycardiaslow heart rate2.6%101
  13. Multiple organ dysfunction syndromeseveral organs failing2.6%100
  14. Sepsisa severe body-wide response to infection2.5%97
  15. Dyspnoeashortness of breath2.4%94
  16. Exposure during pregnancythe medicine was taken during pregnancy2.3%89
  17. Drug exposure during pregnancythe medicine was taken during pregnancy2.2%86
  18. General physical health deteriorationgeneral decline in health2.2%84
  19. Pyrexiafever2.1%83
  20. Premature babya baby born early2%76
  21. Respiratory failurethe lungs could not supply enough oxygen2%76
  22. Stressstress1.9%74
  23. Drug interactionan interaction between medicines1.9%73
  24. Headachehead pain1.9%73
  25. Hyponatraemialow blood sodium1.9%73
  26. Abdominal painstomach or belly pain1.8%72
  27. Diarrhoealoose or frequent stools1.8%69

Top 30 of 626 MedDRA preferred terms recorded across these reports, with a plain-language gloss where one is available. One report can record several terms. The hollow bar is the median share across the 4 drugs in the neuraminidase inhibitor class; it describes the reports, not the patients. FDA states that adverse event reports "represent a small percentage of total usage numbers of a product", that "common products may have a higher number of adverse events due to the higher total number of people using the product", and that the data "by themselves are not an indicator of the safety profile of the drug or biologic."

Outcomes recorded

Death15.1%590
Life-threatening7.3%284
Hospitalisation (initial or prolonged)26.7%1,041
Disability2.6%103
Congenital anomaly3.4%131
Other serious48.7%1,897
Not serious27.2%1,061

Outcome flags as the reporter set them; a report can carry several, and "other serious" is FDA's own category for serious reports outside the named outcomes. Grey bar: all 20,262 reports in the class. FDA has not verified any outcome and states that the reports "cannot be used to estimate the incidence of these events."

Patients and reporters

Patient age

Under 21.8%70
2 to 116.4%248
12 to 173.2%123
18 to 4421.2%828
45 to 6413.5%526
65 to 747%273
75 and over8.4%327
Age not given38.5%1,502

Patient sex

Female39.6%1,543
Male40.2%1,565
Not given20.2%789

Who reported

Physician29.4%1,146
Pharmacist6.8%264
Other health professional52.9%2,061
Lawyer0%1
Consumer or non-health professional8.6%334
Not given2.3%91

Age and sex as stated in the report; the reporter's qualification is the primary source recorded by FDA. 29% of reports give the United States as the country of the event or reporter.

Reason for use recorded

Indication as recorded (MedDRA)ReportsShare
Influenza1,13829.2%
Covid-191,00325.7%
H1n1 influenza1634.2%
Covid-19 pneumonia832.1%
Pneumonia511.3%
Avian influenza491.3%

The indication field is filled in by the reporter and is often blank; shares are of all 3,897 reports.

Drugs most often listed in the same reports

Drug (any role in the report)ReportsShare of Oseltamivir reports
Hydroxychloroquine43511.2%
Azithromycin Anhydrous41210.6%
Ceftriaxone3879.9%
Meropenem2646.8%
Vancomycin2045.2%
Azithromycin1965%
Methylprednisolone1914.9%
Acetaminophen1814.6%
Levofloxacin1263.2%
Prednisone1012.6%

Other products listed in reports where Oseltamivir is a suspect product, whatever their own role. Co-listing means the two were recorded together; it says nothing about either product's part in the event. Only the 2,500 most-reported names are counted here.

In context

MeasureOseltamivirNeuraminidase inhibitorAll reports
Reports as suspect product3,89720,26220,646,523
Share of that pool—19.2%0%
Reports, latest 12 months211—1,332,454
Marked serious72.8%60.6%57.4%
Death recorded among outcomes, per 1,000 reports15110291
Hospitalisation recorded, per 1,000 reports267200213
Consumer-filed share8.6%32.8%45.8%
Top term, share of reportsOff label use 31%median 11%4.1%

Shares are of reports, not of patients treated. The number of people taking a product is not in the data, so none of these figures is a rate, and differences between columns reflect who takes a product, who reports and how long it has been sold. FDA states that adverse event reports "represent a small percentage of total usage numbers of a product", that "common products may have a higher number of adverse events due to the higher total number of people using the product", and that the data "by themselves are not an indicator of the safety profile of the drug or biologic."

Other drugs in the neuraminidase inhibitor class

DrugName typeReportsLatest 12 monthsMarked serious
Tamiflubrand13,22319057.2%
Relenzabrand2,073056.4%
Oseltamivir phosphategeneric1,06912066.9%

Ordered by report count for navigation only. FDA states that adverse event reports "represent a small percentage of total usage numbers of a product", that "common products may have a higher number of adverse events due to the higher total number of people using the product", and that the data "by themselves are not an indicator of the safety profile of the drug or biologic." A brand and its generic are separate rows because reporters name them separately.

Questions about Oseltamivir reports

How many adverse event reports has FDA received for Oseltamivir?

3,897 reports list Oseltamivir as a suspect or interacting product in the openFDA FAERS release of 28 Sep 2026, covering reports received through June 2026. 211 of them arrived in the latest 12 months. Another 2,445 list it only as a concomitant medication.

What reactions are recorded in Oseltamivir reports?

off label use (31%), no adverse event (13.5%), drug ineffective (9.9%), foetal exposure during pregnancy (5.1%) and condition aggravated (4.2%). These are MedDRA preferred terms coded from what the reporter described; a report can list several, and a term's presence is not a finding that Oseltamivir was responsible.

How serious are the reports?

72.8% are marked serious by the reporter. Among the outcomes recorded, 15.1% of reports include death and 26.7% include hospitalisation. FDA has not verified these outcomes and states that the reports "cannot be used to estimate the incidence" of the events.

Who files these reports?

other health professional (52.9%), physician (29.4%) and consumer or non-health professional (8.6%). Most reports reach FDA through the manufacturer, which must forward reports it receives.

Are reports for Oseltamivir rising?

211 reports in the 12 months to June 2026, down 68% from 666 in the 12 months before. FDA releases FAERS data quarterly, so the newest months are incomplete and grow in later releases. Counts also move with how many people take a product, its time on the market and publicity.

Do these reports show that Oseltamivir was responsible for these reactions?

No. FDA states that "a causal relationship cannot be established between product and reactions listed in a report" and that for any given report "there is no certainty that a suspected drug caused the event." The reaction may relate to the condition being treated, to other medicines, or to something else.

Is this a list of the side effects of Oseltamivir?

No. It is a count of what was reported to FDA. The adverse reactions observed in clinical studies are printed on the FDA-approved label, which a pharmacist or clinician can go through with you.

How do I report an adverse event?

Consumers and health professionals can report to FDA through MedWatch (Form FDA 3500 online, or 1-800-FDA-1088), or to the manufacturer, which must pass reports on. See the guide on how to report.

Where this comes from. Counts are built from the openFDA Drug Adverse Event (FAERS) bulk export released 28 Sep 2026, which holds reports FDA received through 30 Jun 2026. Drug names are as reported, resolved to the brand or generic name on the FDA label where openFDA's harmonisation matched them; classes are the pharmacologic class (EPC) from the label and the National Drug Code Directory of 17 Sep 2026. A report counts here when it lists Oseltamivir as a suspect or interacting product; reports listing it only as a concomitant medication (2,445) are excluded. No report narrative, lot number, patient detail or reporter identity is published. See the methodology and sources; FDA's record is authoritative, and corrections are handled within five working days.

Drug data (FAERS) through 30 Jun 2026; device data (MAUDE) through 31 Aug 2026. Not medical advice.