Reported Reactions

Adverse event reports that FDA received

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Low molecular weight heparin adverse event reports that FDA received for the drugs of this class

Kind of class
Pharmacologic class (FDA Established Pharmacologic Class)
Drug pages
2

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 . The data have the reports that FDA received through .

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 .

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 .

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

Low molecular weight heparin is a pharmacologic class: an FDA Established Pharmacologic Class. The class has 2 drug pages on this site.

From January 2004 to June 2026, FDA received 25,243 adverse event reports that name a drug of the class. In these reports the drug is a suspect or interacting product. A report that names two drugs of the class counts one time for each.

FDA received 1,535 reports in the 12 months to June 2026 and 1,813 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.

Pharmacologic class

The Established Pharmacologic Class (EPC) of FDA is the class on the label of a drug. The site puts a drug in the class that its reports have most often.

Data version

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

Drugs of the class

The rows are in order of name. A brand name and its generic name are separate rows, because reporters name them separately.

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 .

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 . The site read the page on .

Drug pages of the class Low molecular weight heparin, in order of name
DrugName typeReportsReports, 12 months to June 2026
Enoxaparin sodiumGeneric name10,060761
LovenoxEnoxaparin sodiumBrand name15,183774

Reaction lookup

These are the reaction terms that the reports of the class record. Type a term or a plain word to find its count.

What this list leaves out

The table lists the 1,083 reaction terms that 5 or more reports record. A term with fewer than 5 reports is not in the table.

The site keeps reaction terms for 25,222 of the 25,243 reports (99.9%).

The reports of the other years are not in the counts.

So a count in the table can be lower than the count of FDA.

The table shows the first 50 of 1,083 terms.

Reaction terms in the reports that name a low molecular weight heparin drug, most reports first
Reaction term (MedDRA) and plain meaningReportsShare of the 25,243 reports
Off label useused for a purpose or in a way not on the label1,2645%
Thrombocytopenialow platelets9883.9%
Anaemialow red blood cells9553.8%
Haematomaa collection of blood under the skin or in tissue8453.3%
Haemorrhagebleeding7883.1%
Pulmonary embolisma blood clot in the lung7543%
Dyspnoeashortness of breath7062.8%
Exposure during pregnancythe medicine was taken during pregnancy6632.6%
Deaththe patient died; cause not stated by this term6312.5%
Drug ineffectivethe medicine did not work as expected6272.5%
Nauseafeeling sick6222.5%
Gastrointestinal haemorrhagebleeding in the stomach or bowel6082.4%
Haemoglobin decreasedlow haemoglobin6082.4%
Drug interactionan interaction between medicines5882.3%
Heparin-induced thrombocytopenia5752.3%
Maternal exposure during pregnancythe mother took the medicine during pregnancy5722.3%
Pruritusitching5682.3%
Abdominal painstomach or belly pain5652.2%
Pyrexiafever5632.2%
Deep vein thrombosisa blood clot in a deep vein5622.2%
Hypotensionlow blood pressure5442.2%
Falla fall5372.1%
Haematuriablood in the urine5372.1%
Injury associated with device5362.1%
Vomitingbeing sick5342.1%
Injection site painpain where the injection was given5252.1%
Device malfunctionthe device did not work properly5232.1%
Condition aggravatedthe condition being treated got worse5162%
Headachehead pain5072%
Foetal exposure during pregnancythe unborn baby was exposed to the medicine5002%
Thrombosis4972%
Shock haemorrhagic4921.9%
Injection site bruisingbruising where the injection was given4881.9%
Diarrhoealoose or frequent stools4821.9%
Astheniaweakness or lack of energy4611.8%
Dizzinesslight-headedness or unsteadiness4521.8%
No adverse eventno adverse event was reported4371.7%
Fatiguetiredness4351.7%
Acute kidney injurysudden loss of kidney function4321.7%
Tachycardiafast heart rate4201.7%
Sepsisa severe body-wide response to infection4191.7%
Rash maculo-papulara rash of flat and raised spots4181.7%
Contusiona bruise4161.6%
Rashskin rash4041.6%
Cholestasis4001.6%
Cardio-respiratory arrestthe heart and breathing stopped3951.6%
Haematemesis3861.5%
Eosinophilia3781.5%
International normalised ratio increasedblood clotting slower than intended (raised INR)3761.5%
Neutropenialow neutrophils, a type of white blood cell3641.4%

Download all 1,083 terms of the class (CSV)

The counts add to more than 25,243 reports, because one report can record more than one term. FDA says:

No individual drug is connected to any individual reaction. 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 .

Reports by month

Reports that name a low molecular weight heparin drug, by month, five years to June 2026
025050020222023202420252026

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

Outcomes, patients and reporters

Outcomes in the reports of the class Low molecular weight heparin
OutcomeReportsShareShare as a bar
Death3,96915.7%
Life-threatening2,0238%
Hospitalization (initial or prolonged)11,18444.3%
Disability or Permanent Damage4911.9%
Congenital Anomaly/Birth Defect2951.2%
Other Serious (Important Medical Events)11,14444.1%
Not serious4,71918.7%

An outcome in a report is not proof that a drug was the cause. The reporter gives the outcome, and FDA does not verify it. A report can have more than one outcome. FDA says:

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 .

Age of the patient in the reports of the class Low molecular weight heparin
AgeReportsShareShare as a bar
Under 21950.8%
2 to 111080.4%
12 to 171250.5%
18 to 443,12812.4%
45 to 645,22620.7%
65 to 744,31417.1%
75 and over5,15320.4%
Age not given6,99427.7%
Type of reporter in the reports of the class Low molecular weight heparin
ReporterReportsShareShare as a bar
Physician6,84027.1%
Pharmacist3,67114.5%
Other health professional7,41229.4%
Lawyer910.4%
Consumer or non-health professional6,12124.2%
Not given1,1084.4%

Official pages

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

Cite this page

Reported Reactions. Low molecular weight heparin: adverse event reports that FDA received. https://reportedreactions.com/class/low-molecular-weight-heparin/ Source: U.S. Food and Drug Administration, openFDA Drug Adverse Event (FAERS) files, release of . Reports received through .

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 class of a drug is the Established Pharmacologic Class that openFDA attaches to its reports most often. When the reports have none, it is the class in the NDC Directory. 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

Which drugs are in the Low molecular weight heparin class on this site?

Enoxaparin sodium and Lovenox, in order of name. The class of a drug comes from the pharmacologic class (EPC) on its FDA label.

Can the table of drugs rank the drugs?

No. FDA says:

Additionally, it is important to remember that adverse event reports represent a small percentage of total usage numbers of a product.

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

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 .

Drugs also differ in the conditions that they treat and in their time on the market.

How does a person report an adverse event?

FDA runs MedWatch, a program that takes voluntary reports from health professionals, patients and consumers. The guide on how to report has the links.