Oseltamivir phosphate: adverse event reports filed with FDA

1,069

reports as suspect product

0% of all reports · about 51 a year

120

reports, 12 months to June 2026

118 in the 12 months before

66.9%

marked serious by the reporter

60.6% across the class

22.6%

record death among outcomes, as reported

242 reports · not verified by FDA

Reports by month, five years

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

2026 covers reports received through June 2026 only.

Reactions recorded in the reports

share of Oseltamivir phosphate reports recording the termmedian drug in neuraminidase inhibitor

1. Vomitingbeing sick22.6%242
2. Nauseafeeling sick20.6%220
3. Off label useused for a purpose or in a way not on the label20.3%217
4. Abdominal painstomach or belly pain16.6%177
5. Abdominal distensiona bloated abdomen16.1%172
6. Appendicitis16%171
7. Ascitesfluid in the abdomen16%171
8. Appendicolith15.7%168
9. Cardiogenic shockshock from the heart failing to pump15.3%164
10. General physical health deteriorationgeneral decline in health15.3%164
11. Constipationconstipation14.9%159
12. Ventricular fibrillationa chaotic rhythm from the lower heart chambers14.9%159
13. Hyponatraemialow blood sodium14.6%156
14. Stressstress14.4%154
15. Multiple organ dysfunction syndromeseveral organs failing14.3%153
16. Sepsisa severe body-wide response to infection14.3%153
17. Blood phosphorus increased13.9%149
18. Condition aggravatedthe condition being treated got worse13.6%145
19. Dry mouthdry mouth12.9%138
20. Somnolencedrowsiness12.2%130
21. Blood cholesterol increasedraised cholesterol11.8%126
22. Blood uric acid increasedraised uric acid10.9%117
23. Anaemialow red blood cells10.7%114
24. Drug intolerancethe medicine was not tolerated10.6%113
25. Dyspnoeashortness of breath10.5%112
26. Drug hypersensitivityan allergic-type reaction to a medicine10.4%111
27. Bacterial infectiona bacterial infection10.3%110
28. Diabetes mellitusdiabetes10.2%109
29. Myasthenia gravis10.1%108
30. Chronic obstructive pulmonary diseaseCOPD, a long-term lung disease9.5%102

Top 30 of 292 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

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

Age and sex as stated in the report; the reporter's qualification is the primary source recorded by FDA. 51.5% of reports give the United States as the country of the event or reporter.

Reason for use recorded

The indication field is filled in by the reporter and is often blank; shares are of all 1,069 reports.

In context

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

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.

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 phosphate as a suspect or interacting product; reports listing it only as a concomitant medication (659) 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.