Leukocytosis adverse event reports that record this term

Kind of term: MedDRA preferred term

What a report is

A report is not proof that the drug was the cause of the event.

FDA says:

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.
Source: openFDA, Drug Adverse Event Overview, section "Responsible use of the data". The site read the page on 2 Oct 2026. The data have the reports that FDA received through 30 Jun 2026.

FDA also says:

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 has not been scientifically or otherwise verified as to a cause and effect relationship and cannot be used to estimate the incidence of these events.
Source: openFDA, Drug Adverse Event Overview. The site read the page on 2 Oct 2026.

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.
Source: openFDA, Response of the drug event API (meta.disclaimer). The site read the page on 2 Oct 2026.

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

Reports on file

From January 2004 to June 2026, FDA received 17,749 adverse event reports that record the MedDRA preferred term Leukocytosis. The person who codes a report selects the term that agrees best with the description of the reporter.

FDA received 1,085 reports in the 12 months to June 2026 and 1,070 in the 12 months before. FDA releases FAERS data every quarter, so the newest months are not complete. They grow in later releases.

The number of people who use the product is not in the data. A count is not a rate.

MedDRA

The Medical Dictionary for Regulatory Activities. The person who codes a report selects the preferred term that agrees best with the description of the reporter. FDA does not publish the description.

Data version

openFDA FAERS release of 1 Oct 2026. Reports received through 30 Jun 2026.

Drugs in these reports

The table has the 145 drug pages with 50 or more reports that record this term. The rows are in order of name. A drug page with fewer reports for this term is not in the table. The counts are the counts that the site keeps for each reaction term, and a count can be lower than the count of FDA.

FDA says:

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.
Source: openFDA, Drug Adverse Event Overview. The site read the page on 2 Oct 2026.

Importantly, the AEMS data by themselves are not an indicator of the safety profile of the drug or biologic.
Source: FDA, FDA Adverse Event Monitoring System (AEMS) Public Dashboard. Content current as of 11 Mar 2026. The site read the page on 2 Oct 2026.

Drugs that the reports with the term Leukocytosis name as a suspect product, in order of name
Drug	Class	Reports with this term
Acetaminophen		335
Acetylcysteine		50
Adalimumab	Tumor necrosis factor blocker	67
Alendronate sodium	Bisphosphonate	129
Allopurinol	Xanthine oxidase inhibitor	135
Alprazolam	Benzodiazepine	55
Amisulpride	Dopamine-2 receptor antagonist	50
Amlodipine	Calcium channel blocker	248
Amoxicillin	Penicillin-class antibacterial	91
Apixaban	Factor Xa inhibitor	59
Aredia		62
Aripiprazole	Atypical antipsychotic	118
Aspirin	Nonsteroidal anti-inflammatory drug	136
Atorvastatin		87
Augmentin '125		59
Avastin	Vascular endothelial growth factor inhibitor	55
Azacitidine	Nucleoside metabolic inhibitor	91
Azathioprine	Purine antimetabolite	67
Azithromycin	Macrolide antimicrobial	70
Azithromycin Anhydrous		53
Baclofen	gamma-Aminobutyric acid-ergic agonist	52
Bevacizumab	Vascular endothelial growth factor inhibitor	88
Bupropion	Aminoketone	62
Capecitabine	Nucleoside metabolic inhibitor	80
Carbamazepine	Mood stabilizer	130
Carboplatin	Platinum-based drug	197
Ceftriaxone	Cephalosporin antibacterial	119
Ciprofloxacin	Fluoroquinolone antibacterial	176
Cisplatin	Platinum-based drug	159
Clindamycin	Lincosamide antibacterial	78
Clonazepam	Benzodiazepine	95
Clozapine	Atypical antipsychotic	549
Clozaril	Atypical antipsychotic	1,212
Codeine		70
Colchicine	Alkaloid	156
Cyclophosphamide	Alkylating drug	281
Cyclosporine	Calcineurin inhibitor immunosuppressant	79
Cytarabine	Nucleoside metabolic inhibitor	101
Dasatinib	Kinase inhibitor	72
Dexamethasone	Corticosteroid	248
Diazepam	Benzodiazepine	88
Diclofenac	Nonsteroidal anti-inflammatory drug	69
Diclofenac sodium	Nonsteroidal anti-inflammatory drug	60
Digoxin	Cardiac glycoside	94
Docetaxel	Microtubule inhibitor	181
Doxorubicin	Anthracycline topoisomerase inhibitor	96
Doxorubicin hydrochloride	Anthracycline topoisomerase inhibitor	85
Doxycycline	Tetracycline-class drug	62
Duloxetine	Serotonin and norepinephrine reuptake inhibitor	51
Dupixent	Interleukin-4 receptor alpha antagonist	63
Enbrel	Tumor necrosis factor blocker	91
Etoposide	Topoisomerase inhibitor	98
Exjade	Iron chelator	77
Fentanyl	Opioid agonist	74
Filgrastim	Leukocyte growth factor	76
Fluorouracil	Nucleoside metabolic inhibitor	194
Fluoxetine	Serotonin reuptake inhibitor	92
Fosamax	Bisphosphonate	244
Furosemide	Loop diuretic	124
Gabapentin	Anti-epileptic agent	66
Gemcitabine	Nucleoside metabolic inhibitor	83
Gleevec	Kinase inhibitor	71
Glivec		113
Haloperidol	Typical antipsychotic	127
Heparin sodium	Anti-coagulant	114
Humira		221
Hydrochlorothiazide	Thiazide diuretic	81
Hydroxyurea	Antimetabolite	63
Ibrutinib	Kinase inhibitor	89
Ibuprofen	Nonsteroidal anti-inflammatory drug	281
Imatinib	Kinase inhibitor	107
Imbruvica	Kinase inhibitor	166
Infliximab	Tumor necrosis factor blocker	56
Insulin	Insulin analog	67
Irinotecan		55
Jakafi	Janus kinase inhibitor	168
Jakavi		100
Januvia	Dipeptidyl peptidase 4 inhibitor	79
Lacosamide		56
Lamotrigine	Anti-epileptic agent	142
Lansoprazole	Proton pump inhibitor	61
Leponex		72
Leucovorin		60
Leucovorin calcium	Folate analog	55
Levetiracetam		84
Levofloxacin	Fluoroquinolone antibacterial	102
Lisinopril	Angiotensin converting enzyme inhibitor	97
Lithium	Mood stabilizer	123
Lithium carbonate	Mood stabilizer	66
Lorazepam	Benzodiazepine	155
Meropenem	Penem antibacterial	100
Metformin	Biguanide	322
Metformin hydrochloride	Biguanide	66
Methotrexate	Folate analog metabolic inhibitor	226
Methylprednisolone	Corticosteroid	225
Metronidazole	Nitroimidazole antimicrobial	113
Morphine	Opioid agonist	63
Mycophenolate mofetil	Antimetabolite immunosuppressant	178
Neulasta	Leukocyte growth factor	198
Neupogen	Leukocyte growth factor	63
Nivolumab	Programmed death Receptor-1 blocking antibody	70
Nplate	Thrombopoietin receptor agonist	63
NuvaRing	Estrogen	114
Olanzapine	Atypical antipsychotic	242
Omeprazole	Proton pump inhibitor	123
Oxaliplatin	Platinum-based drug	168
Oxycodone	Opioid agonist	61
Paclitaxel	Microtubule inhibitor	137
Pantoprazole	Proton pump inhibitor	89
Paracetamol		69
Pegfilgrastim	Leukocyte growth factor	80
Pembrolizumab	Programmed death Receptor-1 blocking antibody	53
Phenytoin	Anti-epileptic agent	66
Piperacillin and tazobactam	Penicillin-class antibacterial	68
Piperacillin sodium,tazobactam sodium		53
Pradaxa	Direct thrombin inhibitor	74
Prednisolone	Corticosteroid	234
Prednisone	Corticosteroid	527
Propofol	General anesthetic	67
Quetiapine	Atypical antipsychotic	137
Ramipril	Angiotensin converting enzyme inhibitor	55
Remicade	Tumor necrosis factor blocker	72
Revlimid	Thalidomide analog	53
Risperdal	Atypical antipsychotic	64
Risperidone	Atypical antipsychotic	142
Rituximab	CD20-directed cytolytic antibody	263
Rosuvastatin	HMG-CoA reductase inhibitor	59
Ruxolitinib	Janus kinase inhibitor	80
Sertraline	Serotonin reuptake inhibitor	60
Simvastatin	HMG-CoA reductase inhibitor	87
Tacrolimus	Calcineurin inhibitor immunosuppressant	222
Tasigna	Kinase inhibitor	129
Tocilizumab	Interleukin-6 receptor antagonist	50
Tramadol		88
Trastuzumab	HER2/neu receptor antagonist	87
Trazodone		59
Tysabri	Integrin receptor antagonist	140
Valproic acid	Anti-epileptic agent	100
Vancomycin	Glycopeptide antibacterial	226
Venetoclax	BCL-2 inhibitor	112
Vidaza	Nucleoside metabolic inhibitor	51
Vincristine		93
Vioxx		119
Zometa		111
Zyprexa	Atypical antipsychotic	87

The page of each drug has the count of each reaction term in its reaction lookup.

Drug classes in these reports

The table has the 54 pharmacologic classes with 100 or more reports that record this term. The rows are in order of name.

FDA says:

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.
Source: openFDA, Drug Adverse Event Overview. The site read the page on 2 Oct 2026.

Importantly, the AEMS data by themselves are not an indicator of the safety profile of the drug or biologic.
Source: FDA, FDA Adverse Event Monitoring System (AEMS) Public Dashboard. Content current as of 11 Mar 2026. The site read the page on 2 Oct 2026.

Pharmacologic classes of the drugs that the reports with the term Leukocytosis name, in order of name
Class	Reports with this term
Alkaloid	156
Alkylating drug	379
Angiotensin 2 receptor blocker	134
Angiotensin converting enzyme inhibitor	201
Anthracycline topoisomerase inhibitor	200
Anti-coagulant	117
Anti-epileptic agent	499
Antimetabolite immunosuppressant	260
Atypical antipsychotic	2,707
BCL-2 inhibitor	137
Benzodiazepine	627
beta-Adrenergic blocker	170
Biguanide	457
Bisphosphonate	434
Calcineurin inhibitor immunosuppressant	364
Calcium channel blocker	258
CD20-directed cytolytic antibody	343
Cephalosporin antibacterial	264
Corticosteroid	1,433
Dipeptidyl peptidase 4 inhibitor	109
Estrogen	119
Factor Xa inhibitor	198
Fluoroquinolone antibacterial	303
Folate analog metabolic inhibitor	299
Glycopeptide antibacterial	235
HER2/neu receptor antagonist	180
HMG-CoA reductase inhibitor	194
Integrin receptor antagonist	169
Janus kinase inhibitor	336
Kinase inhibitor	1,016
Leukocyte growth factor	417
Loop diuretic	213
Macrolide antimicrobial	106
Microtubule inhibitor	346
Mood stabilizer	356
Nitroimidazole antimicrobial	131
Nonsteroidal anti-inflammatory drug	689
Nucleoside metabolic inhibitor	706
Opioid agonist	489
Penem antibacterial	117
Penicillin-class antibacterial	263
Platinum-based drug	524
Programmed death Receptor-1 blocking antibody	225
Proton pump inhibitor	326
Serotonin and norepinephrine reuptake inhibitor	147
Serotonin reuptake inhibitor	314
Sodium-Glucose cotransporter 2 inhibitor	101
Thalidomide analog	103
Thrombopoietin receptor agonist	100
Topoisomerase inhibitor	134
Tumor necrosis factor blocker	338
Typical antipsychotic	131
Vascular endothelial growth factor inhibitor	169
Xanthine oxidase inhibitor	135

A class with many reports in all has many reports for almost every term.

Reports by month

Reports that record Leukocytosis, by month, five years to June 2026

FDA releases FAERS data every quarter, so the newest months are not complete. They grow in later releases.

Patients in these reports

Age of the patient in the reports that record Leukocytosis
Age	Reports	Share
Under 2	142	0.8%
2 to 11	290	1.6%
12 to 17	477	2.7%
18 to 44	3,633	20.5%
45 to 64	4,792	27%
65 to 74	2,547	14.4%
75 and over	1,976	11.1%
Age not given	3,892	21.9%

Sex of the patient in the reports that record Leukocytosis
Sex	Reports	Share
Female	8,077	45.5%
Male	8,205	46.2%
Unknown or not given	1,467	8.3%

Age and sex are as the report gives them. 41.3% of these reports give the United States as the country.

Terms near this one

These are the next terms in the A to Z list. The links are for navigation.

Official pages

MedWatch Online Voluntary Reporting FormThe online form of FDA for a voluntary report.
MedWatch: The FDA Safety Information and Adverse Event Reporting ProgramThe page of the FDA program that receives reports about drugs and devices.
FDA Adverse Event Monitoring System (AEMS) Public DashboardThe public dashboard of FDA for adverse event reports on drugs and biologics.

The site checked these addresses on 2 Oct 2026. The links open in a new tab.

Cite this page

Reported Reactions. Leukocytosis: adverse event reports that record this term. https://reportedreactions.com/reaction/leukocytosis/ Source: U.S. Food and Drug Administration, openFDA Drug Adverse Event (FAERS) files, release of 1 Oct 2026. Reports received through 30 Jun 2026.

Where the data come from

The counts come from the openFDA Drug Adverse Event (FAERS) bulk files, release of 1 Oct 2026. The files have the reports that FDA received through 30 Jun 2026. A drug name is the name on the report. The site matches it to a brand name or a generic name of the National Drug Code Directory of 2 Oct 2026. A class is the pharmacologic class (EPC) of the FDA label.

The count has the reports with each spelling of one MedDRA preferred term. The site does not publish a report narrative, a lot number, a detail of a patient or the identity of a reporter. The record of FDA is the authority. See how the site counts reports, the data sources and the corrections page.

Questions

What does Leukocytosis mean in an adverse event report?

It is a MedDRA preferred term. FDA codes the description of a reporter with the MedDRA dictionary. The openFDA files do not have the description itself, and this site does not show it.

Does a drug in the table mean that the drug was responsible for this reaction?

No. FDA says:

No individual drug is connected to any individual reaction.
Source: openFDA, Drug Adverse Event Overview. The site read the page on 2 Oct 2026.

When a report lists multiple drugs and multiple reactions, there is no way to conclude from the data therein that a given drug is responsible for a given reaction.
Source: openFDA, Drug Adverse Event Overview. The site read the page on 2 Oct 2026.

What does this page tell a person who has this symptom?

This page gives counts of reports. It cannot assess a person. A pharmacist or a clinician can assess a person.

If this is a medical emergency, please call 911.
Source: FDA, MedWatch Online Voluntary Reporting Form. The site read the page on 2 Oct 2026.

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