Pharmacologic class (EPC) · 23 drug pages

Alkylating drug: adverse event reports filed with FDA

253,205 reports list a drug in this class as a suspect or interacting product, 2004–2026.

Read first · FDA's statement on these data

Adverse event reports submitted to FDA do not undergo extensive validation or verification. Therefore, a causal relationship cannot be established between product and reactions listed in a report. While a suspected relationship may exist, it is not medically validated and should not be the sole source of information for clinical decision making or other assumptions about the safety or efficacy of a product. Additionally, it is important to remember that adverse event reports represent a small percentage of total usage numbers of a product. Common products may have a higher number of adverse events due to the higher total number of people using the product. openFDA, FDA

FDA adds: "There is no certainty that the reported event (adverse event or medication error) was actually due to the product. FDA does not require that a causal relationship between a product and event be proven, and reports do not always contain enough detail to properly evaluate an event." The information in these reports "cannot be used to estimate the incidence of these events."

Do not rely on openFDA to make decisions regarding medical care. While we make every effort to ensure that data is accurate, you should assume all results are unvalidated.

Not medical advice. This site counts what was reported to FDA. Questions about a medicine or device belong with a pharmacist or clinician.

253,205
reports across the class: 1.2% of all reports; 19,663
reports, 12 months to June 2026: 21,675 in the 12 months before; 93.5%
marked serious by the reporter: 57.4% across all reports; 23
drugs with a page: brand and generic names counted separately

Alkylating drug is a pharmacologic class (an FDA Established Pharmacologic Class) with 23 drug pages on this site. Together those drugs are listed as a suspect or interacting product in 253,205 adverse event reports received by FDA, 1.2% of the database, from January 2004 to June 2026.

19,663 reports arrived in the 12 months to June 2026, close to the 21,675 of the 12 months before. FDA releases FAERS data quarterly, so the newest months are incomplete and grow in later releases. 93.5% of the class's reports are marked serious, 20.8% record death among the outcomes and 33.3% record hospitalisation, as reported.

Across the class the reactions recorded most often are off label use (9.4%), febrile neutropenia (8.1%) and neutropenia (5.9%). The class median share shown beside each term is the middle value across the member drugs; it is the comparison used on every drug page in this class.

The members table is 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."

Drugs in the class

Drug	Name type	Reports	Latest 12 months	Marked serious	Top term recorded
Cyclophosphamide	generic	141,099	12,360	97.8%	Febrile neutropenia
Ifosfamide	generic	18,658	1,325	98.2%	Febrile neutropenia
Melphalan	generic	17,190	956	98.5%	Off label use
Temozolomide	generic	15,324	1,055	82.3%	Disease progression
Busulfan	generic	11,825	1,095	94.9%	Product use in unapproved indication
Thiotepa	generic	7,853	1,035	98.8%	Off label use
Bendamustine hydrochloride	generic	6,941	253	96%	Off label use
Dacarbazine	generic	6,431	511	96.3%	Febrile neutropenia
TemodarTemozolomide	brand	4,652	24	56.1%	Product use in unapproved indication
MatulaneProcarbazine hydrochloride	brand	3,845	284	15.9%	Nausea
Carmustine	generic	3,378	180	99%	Off label use
TreandaBendamustine hydrochloride	brand	3,330	3	66.5%	Rash
Chlorambucil	generic	2,486	75	98.5%	Pneumonia
ValchlorMechlorethamine hydrochloride	brand	2,114	16	28.4%	Pruritus
Mitomycin	generic	2,041	117	92.4%	Off label use
Lomustine	generic	1,100	92	94.8%	Thrombocytopenia
YondelisTrabectedin	brand	1,099	57	84.8%	Pancytopenia
Trabectedin	generic	1,099	99	98.3%	Neutropenia
ZepzelcaLurbinectedin	brand	602	57	72.1%	Disease progression
Procarbazine hydrochloride	generic	557	30	99.8%	Hepatic cytolysis
IfexIfosfamide	brand	543	11	96.7%	Sepsis
GliadelCarmustine	brand	523	2	95.4%	Brain oedema
GleostineLomustine	brand	515	26	61.4%	Death

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."

Reports by month, five years

FDA releases FAERS data quarterly, so the newest months are incomplete and grow in later releases.

Reactions recorded across the class

share of class reports recording the termmedian drug in the class

Off label useused for a purpose or in a way not on the label9.4%23,820
Febrile neutropeniafever with low white blood cells8.1%20,535
Neutropenialow neutrophils, a type of white blood cell5.9%14,942
Drug ineffectivethe medicine did not work as expected5.6%14,057
Disease progressionthe disease advanced5.4%13,735
Pyrexiafever4.7%11,879
Thrombocytopenialow platelets4.5%11,289
Product use in unapproved indicationused for a purpose not on the label4.4%11,230
Nauseafeeling sick3.8%9,646
Anaemialow red blood cells3.5%8,885
Pneumonialung infection3.4%8,626
Sepsisa severe body-wide response to infection3.2%8,210
Deaththe patient died; cause not stated by this term3.1%7,787
Diarrhoealoose or frequent stools3%7,648
Vomitingbeing sick2.9%7,278
Infectionan infection, type not specified2.8%7,021
Mucosal inflammation2.7%6,866
Pancytopenialow counts of all blood cells2.7%6,744
Fatiguetiredness2.4%6,197
Myelosuppression2.2%5,445
Malignant neoplasm progression2.1%5,239
White blood cell count decreasedlow white cell count1.9%4,801
Dyspnoeashortness of breath1.7%4,269
Platelet count decreasedlow platelet count1.7%4,227
Neuropathy peripheralnerve damage in hands or feet1.7%4,185

Solid bar: share of all class reports. Hollow bar: the median share across the 23 member drugs, the reference used on each member's page. One report can record several terms.

Outcomes, patients and reporters

Outcomes recorded

Death20.8%52,615

Life-threatening7.5%18,869

Hospitalisation (initial or prolonged)33.3%84,332

Disability1.3%3,199

Congenital anomaly0.2%590

Other serious64.4%162,942

Not serious6.5%16,465

Patient age

Under 21.7%4,297

2 to 116.3%16,077

12 to 173.9%9,796

18 to 4413.6%34,346

45 to 6423.2%58,660

65 to 7412.6%31,865

75 and over6.2%15,651

Age not given32.6%82,513

Who reported

Physician41.3%104,474

Pharmacist3.7%9,396

Other health professional43.7%110,678

Lawyer0.1%180

Consumer or non-health professional6.3%15,872

Not given5%12,605

Grey bar: all 20,646,523 reports in the database. Outcome flags are as the reporter set them and are not verified by FDA.

Questions about Alkylating drug reports

Which drugs are in the Alkylating drug class on this site?

Cyclophosphamide, Ifosfamide, Melphalan, Temozolomide, Busulfan and Thiotepa and 17 more. Class membership comes from the pharmacologic class (EPC) on the drug's FDA label.

How many reports does the class have?

253,205 reports through June 2026, 19,663 of them in the latest 12 months. A report listing two drugs of the class counts once for each.

What reactions are recorded most often?

off label use (9.4%), febrile neutropenia (8.1%), neutropenia (5.9%), drug ineffective (5.6%) and disease progression (5.4%).

Can the members table be used to rank the drugs?

No. 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." Drugs differ in how many people take them, in the conditions they treat, in time on the market and in how diligently reports are collected.

How do I report an adverse event?

Through FDA MedWatch (Form FDA 3500, or 1-800-FDA-1088) or to the manufacturer. 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 class is the Established Pharmacologic Class most often attached to a drug's reports by openFDA's label harmonisation, or from the NDC Directory where reports carry none. 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.