Cyclophosphamide: adverse event reports filed with FDA

141,099

reports as suspect product

0.7% of all reports · about 6,273 a year

12,360

reports, 12 months to June 2026

13,414 in the 12 months before

97.8%

marked serious by the reporter

93.5% across the class

20.5%

record death among outcomes, as reported

28,981 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 Cyclophosphamide reports recording the termmedian drug in alkylating drug

1. Febrile neutropeniafever with low white blood cells9.2%12,947
2. Off label useused for a purpose or in a way not on the label9%12,764
3. Neutropenialow neutrophils, a type of white blood cell6.3%8,854
4. Drug ineffectivethe medicine did not work as expected5.9%8,320
5. Disease progressionthe disease advanced5.2%7,284
6. Pyrexiafever5%7,047
7. Product use in unapproved indicationused for a purpose not on the label3.9%5,516
8. Thrombocytopenialow platelets3.9%5,491
9. Pneumonialung infection3.8%5,394
10. Anaemialow red blood cells3.7%5,171
11. Nauseafeeling sick3.6%5,047
12. Sepsisa severe body-wide response to infection3.5%4,880
13. Diarrhoealoose or frequent stools2.9%4,142
14. Deaththe patient died; cause not stated by this term2.9%4,104
15. Vomitingbeing sick2.9%4,035
16. Myelosuppression2.8%3,896
17. Infectionan infection, type not specified2.7%3,859
18. Pancytopenialow counts of all blood cells2.6%3,704
19. White blood cell count decreasedlow white cell count2.3%3,307
20. Fatiguetiredness2.2%3,125
21. Mucosal inflammation2.2%3,098
22. Neuropathy peripheralnerve damage in hands or feet2%2,787
23. Dyspnoeashortness of breath1.9%2,731
24. Leukopenialow white blood cells1.9%2,666
25. Septic shockshock arising from infection1.8%2,591
26. Malignant neoplasm progression1.8%2,584
27. Astheniaweakness or lack of energy1.8%2,472
28. Respiratory failurethe lungs could not supply enough oxygen1.7%2,428
29. Cytokine release syndrome1.7%2,423
30. Neutrophil count decreased1.6%2,295

Top 30 of 5,398 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 23 drugs in the alkylating drug 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 253,205 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. 24.2% 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 141,099 reports.

Drugs most often listed in the same reports

Other products listed in reports where Cyclophosphamide 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 alkylating drug 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 Cyclophosphamide as a suspect or interacting product; reports listing it only as a concomitant medication (39,413) 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.