MedDRA preferred term

Full blood count decreased: adverse event reports recording this term

19,892 reports to FDA record it, 2004–2026; 0.1% of the database.

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.

19,892
reports recording the term: 0.1% of all reports; 1,077
reports, 12 months to June 2026: 1,391 in the 12 months before; 69%
marked serious by the reporter: 57.4% across all reports; 4.7%
record death among outcomes, as reported: 9.1% across all reports

"Full blood count decreased" is a MedDRA preferred term recorded in 19,892 adverse event reports received by FDA, 0.1% of the database, from January 2004 to June 2026. The term is chosen by whoever codes the report to match what the reporter described.

1,077 reports recorded it in the 12 months to June 2026, down 23% from 1,391 in the 12 months before. FDA releases FAERS data quarterly, so the newest months are incomplete and grow in later releases. Of reports recording this term, 69% are marked serious, 4.7% include death among the outcomes and 34% include hospitalisation, as reported.

The drugs listed most often as suspect products in those reports are Revlimid, Ibrance and Pomalyst. That order mostly follows how many reports each drug has overall; the table also gives the term's share within each drug's own reports. 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

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

Drugs listed as suspect products in these reports

Drug	Class	Reports with this term	Share of the drug's own reports
Revlimid	Thalidomide analog	6,992	2%
Ibrance	Kinase inhibitor	1,927	2.4%
Pomalyst	Thalidomide analog	1,734	2%
Venclexta	BCL-2 inhibitor	452	1.3%
Jakafi	Janus kinase inhibitor	422	0.8%
Lenalidomide	Thalidomide analog	352	0.6%
Pegasys	Interferon alpha	242	0.6%
Zejula	Poly(ADP-Ribose) polymerase inhibitor	241	1.6%
Humira	—	235	0%
Kisqali	Kinase inhibitor	173	0.7%
Dexamethasone	Corticosteroid	168	0.1%
Thalomid	—	156	0.7%
Ribavirin	Nucleoside analog antiviral	141	0.3%
Sprycel	Kinase inhibitor	136	0.5%
Cyclophosphamide	Alkylating drug	132	0.1%
Lynparza	Poly(ADP-Ribose) polymerase inhibitor	124	0.9%
Ninlaro	Proteasome inhibitor	123	1.1%
Xpovio	Nuclear export inhibitor	122	2.7%
Vumerity	—	118	1%
Soliris	Complement inhibitor	116	0.2%
Niraparib	Poly(ADP-Ribose) polymerase inhibitor	113	1.7%
Methotrexate	Folate analog metabolic inhibitor	111	0.1%
Gilenya	Sphingosine 1-phosphate receptor modulator	109	0.1%
Glivec	—	99	0.5%
Cytarabine	Nucleoside metabolic inhibitor	97	0.2%

Drugs with a page on this site, ordered by the number of their reports recording this term. The last column is the term's share within that drug's own reports, against 0.1% across the whole database. 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."

By pharmacologic class

Class	Reports with this term	Share of class reports	Median drug in class
Thalidomide analog	9,098	1.8%	1.3%
Kinase inhibitor	3,151	0.4%	0%
Janus kinase inhibitor	598	0.2%	0%
Poly(ADP-Ribose) polymerase inhibitor	538	1%	0.9%
BCL-2 inhibitor	519	0.9%	0.8%
Nucleoside metabolic inhibitor	439	0.1%	0.1%
Proteasome inhibitor	308	0.3%	0.2%
Corticosteroid	281	0%	0%
Interferon alpha	247	0.6%	0.4%
Alkylating drug	195	0.1%	0%

Classes ordered by count. Class shares follow the class's overall report volume as much as anything else.

Patients in these reports

Patient age

Under 20.1%24

2 to 110.4%89

12 to 170.4%74

18 to 443.7%732

45 to 6417.8%3,540

65 to 7419.9%3,966

75 and over19.7%3,916

Age not given38%7,551

Patient sex

Female56.2%11,171

Male37.3%7,425

Not given6.5%1,296

Grey bar: all 20,646,523 reports in the database. 86.6% of these reports give the United States as the country.

Questions about "Full blood count decreased"

What does "Full blood count decreased" mean in an adverse event report?

It is a MedDRA preferred term, the dictionary FDA uses to code what a reporter described. The report's own description is not published by openFDA and is not shown here.

How many reports record full blood count decreased?

19,892 reports through June 2026 (0.1% of all reports), 1,077 of them in the latest 12 months.

Which drugs appear most often in these reports?

Revlimid (6,992), Ibrance (1,927), Pomalyst (1,734), Venclexta (452) and Jakafi (422). Drugs with many reports overall lead almost every term's list. 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."

Does a drug appearing here mean it was responsible for this reaction?

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."

I have this symptom. What should I do?

This site cannot assess anyone. A pharmacist or clinician can; for an emergency, call the local emergency number. Nothing on this page is medical advice.

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. Terms are pooled across spelling and capitalisation variants of one MedDRA preferred term. 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.