Fludarabine phosphate: adverse event reports filed with FDA

8,426

reports as suspect product

0% of all reports · about 375 a year

419

reports, 12 months to June 2026

477 in the 12 months before

98.5%

marked serious by the reporter

92.2% across the class

31.6%

record death among outcomes, as reported

2,659 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 Fludarabine phosphate reports recording the termmedian drug in nucleoside metabolic inhibitor

1. Off label useused for a purpose or in a way not on the label15.5%1,305
2. Pyrexiafever8.6%721
3. Febrile neutropeniafever with low white blood cells8.1%682
4. Product use in unapproved indicationused for a purpose not on the label6%506
5. Neutropenialow neutrophils, a type of white blood cell5.9%501
6. Drug ineffectivethe medicine did not work as expected4.2%357
7. Thrombocytopenialow platelets4.1%347
8. Pancytopenialow counts of all blood cells4.1%345
9. Cytomegalovirus infection4.1%344
10. Sepsisa severe body-wide response to infection4%341
11. Mucosal inflammation4%336
12. Cytokine release syndrome3.9%328
13. Infectionan infection, type not specified3.4%286
14. Pneumonialung infection3.4%283
15. Cytomegalovirus infection reactivation3.2%272
16. Graft versus host disease3%256
17. Respiratory failurethe lungs could not supply enough oxygen2.9%248
18. Anaemialow red blood cells2.9%244
19. Bone marrow failure2.9%243
20. Acute myeloid leukaemia2.9%242
21. Myelodysplastic syndrome2.7%230
22. Diarrhoealoose or frequent stools2.7%227
23. Nauseafeeling sick2.5%210
24. Septic shockshock arising from infection2.4%200
25. Adenovirus infection2.3%198
26. Deaththe patient died; cause not stated by this term2.3%195
27. Platelet count decreasedlow platelet count2.3%193
28. Venoocclusive liver disease2.3%193
29. Acute graft versus host disease2.1%180
30. Multiple organ dysfunction syndromeseveral organs failing2.1%180

Top 30 of 1,328 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 19 drugs in the nucleoside metabolic 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 313,386 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. 20.9% 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 8,426 reports.

Drugs most often listed in the same reports

Other products listed in reports where Fludarabine phosphate 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

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 nucleoside metabolic 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 Fludarabine phosphate as a suspect or interacting product; reports listing it only as a concomitant medication (2,236) 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.