This page shows what was measured, who it was measured in, and what that does not settle.
What Enoxaparin does in the body
Preventing and treating blood clots in the legs and lungs, and in heart attacks
Your blood already contains a natural brake on clotting called antithrombin, which works slowly on its own. Enoxaparin latches onto antithrombin and forces it into a shape that inactivates the clotting enzyme factor Xa hundreds of times faster. Because enoxaparin’s chains are short, most of them can accelerate the attack on factor Xa but are too short to bring antithrombin and thrombin together at the same time, so it acts mainly one step upstream. The effect is predictable enough from body weight that most people need no blood tests, which is the practical reason it replaced older heparin infusions.
What happened in people
Death or nonfatal reinfarction 9.9% against 12.0% on unfractionated heparin in 20,506 fibrinolysis patients, with major bleeding 2.1% against 1.4%
✎ Source-linked record
Where this came from
A person wrote this into the record with the study named beside it. No reviewer has signed it off.
The recorded finding that sits closest to something a person would notice. Written into the record, not signed off, and it carries no population or interval.
That enoxaparin reduces mortality after fibrinolysis — death alone was 6.9% against 7.5%, p=0.11, and the composite moved on reinfarction
Where it acts
Blood plasma, at the antithrombin III molecule circulating there — not inside any cell
Kind of result
Living longer, or avoiding a major event
Supervision
Professional supervision is normally required. A regulator classifies this substance in a way that restricts how it is supplied.
What the registries record it as
The substance registry classes this as polymer.
FDA substance registry · E47C0NF7LV · read 2026-08-29
Where each sentence above came from
No recorded sentence describes the change this makes in a way that stands on its own. The page opens with what it is taken for instead, and the recorded explanation follows below.
Shown as the opening line on this page.
A limit recorded against this substance. Not signed off as a reviewed claim.
The four opening statements run to 140 words.
Words this page uses
Four words worth knowing first
Chosen from what this page shows, with each one explained before the word it depends on.
Comparator
A comparator is whatever the treatment was measured against.
A picture of it, and where the picture fails
It is like the other runner in a race.
Where that stops being true. A race has one winner. A study can show both arms improved.
What people get wrong. Results are read without asking what the other group got. Beating nothing is not beating a treatment.
The control condition against which the experimental intervention is assessed.
Randomisation
Randomisation means chance decides who gets which treatment.
A picture of it, and where the picture fails
It is like a coin toss deciding the groups.
Where that stops being true. A coin toss is fair once. Fairness here comes from doing it for everyone.
What people get wrong. It is thought to make groups identical. It makes them similar on average, including on things nobody measured.
Allocation of participants to arms by a chance process, so that unmeasured factors are balanced in expectation.
Absolute difference
An absolute difference is how many more people in a hundred were affected.
A picture of it, and where the picture fails
It is like counting heads in two rooms of a hundred.
Where that stops being true. Heads are easy to count. Study results carry a margin of error too.
What people get wrong. It is confused with a percentage change, which can look far larger.
The arithmetic difference in event rates between arms.
Confidence interval
A confidence interval is the range the true answer is likely to sit in.
A picture of it, and where the picture fails
It is like a weather forecast giving a range rather than one number.
Where that stops being true. A forecast range covers tomorrow. This one covers what the study could resolve.
What people get wrong. The middle number is read as the answer. A range crossing zero means no change is still possible.
An interval estimate that would contain the true parameter in a stated proportion of repeated studies.
What happened in people◇Read from sources, not yet reviewed
What happened in people
Each card is one study: the exact question it asked, who was in it, and whether it showed what it set out to show.
Death or nonfatal recurrent myocardial infarction through 30 days, enoxaparin throughout hospitalisation versus unfractionated heparin for at least 48 hours, in patients receiving fibrinolysis
9.9% vs 12.0%, a 17% relative risk reduction, p<0.001. Reinfarction alone 3.0% vs 4.5%, p<0.001. Death alone 6.9% vs 7.5%, p=0.11
Repeated elsewhere
Partially Replicated
What this does not prove. Meeting one endpoint in one population does not carry to other goals or other people.
The limits of this study, and where it came from
Main limit. Major bleeding was 2.1% on enoxaparin against 1.4% on unfractionated heparin, p<0.001. The comparator received only 48 hours of treatment against enoxaparin’s full hospitalisation, so duration and drug are confounded.
How far it carries. This study is recorded from the curated record, not from the registry match.
Form and route. Subcutaneous injection from a prefilled syringe, once or twice daily
Interval reported. Not recorded in this summary
Written into the record, not signed off as a reviewed claim.
All-cause death or nonfatal myocardial infarction at 30 days, enoxaparin versus unfractionated heparin in high-risk non-ST-elevation acute coronary syndrome managed with an intended early invasive strategy
14.0% vs 14.5%, odds ratio 0.96 (95% CI 0.86 to 1.06) — non-inferior, superiority not demonstrated
Repeated elsewhere
Replicated
What this does not prove. A study that did not show an effect does not show that no effect exists anywhere.
The limits of this study, and where it came from
Main limit. TIMI major bleeding 9.1% vs 7.6%, p=0.008. Open-label, and a substantial proportion of patients crossed between anticoagulants before randomisation, which the investigators identified as a confounder.
How far it carries. This study is recorded from the curated record, not from the registry match.
Form and route. Subcutaneous injection from a prefilled syringe, once or twice daily
Interval reported. 95% CI 0
Written into the record, not signed off as a reviewed claim.
Death, myocardial infarction or refractory ischaemia at nine days, fondaparinux versus enoxaparin in acute coronary syndromes
✓ The study showed what it set out to show
Who was studied
OASIS-5 (NCT00139815)
How many people
20078
Study design
Phase 3 randomised double-blind non-inferiority trial, mean 6 days of treatment
Compared against
Not recorded for this study
Kind of result
Living longer, or avoiding a major event
What was found
5.8% vs 5.7%, hazard ratio 1.01 (95% CI 0.90 to 1.13), meeting non-inferiority. Major bleeding at nine days 2.2% vs 4.1%, hazard ratio 0.52, p<0.001
Repeated elsewhere
Unreplicated
What this does not prove. Meeting one endpoint in one population does not carry to other goals or other people.
The limits of this study, and where it came from
Main limit. Enoxaparin was the losing arm on safety: deaths at 30 days 352 against 295 (p=0.02) and at 180 days 638 against 574 (p=0.05). Fondaparinux carried its own excess of catheter thrombosis during percutaneous coronary intervention.
How far it carries. This study is recorded from the curated record, not from the registry match.
Form and route. Subcutaneous injection from a prefilled syringe, once or twice daily
Interval reported. 95% CI 0
Written into the record, not signed off as a reviewed claim.
0.78% vs 0.73%, difference 0.05 percentage points (96.2% CI -0.27 to 0.38), p<0.001 against a 0.75-point non-inferiority margin
Repeated elsewhere
Unreplicated
What this does not prove. Meeting one endpoint in one population does not carry to other goals or other people.
The limits of this study, and where it came from
Main limit. Deep vein thrombosis was significantly higher on aspirin, 2.51% against 1.71% (difference 0.80 points, 95% CI 0.28 to 1.31). Post-discharge prophylaxis followed each hospital’s own protocol rather than the randomised assignment.
How far it carries. This study is recorded from the curated record, not from the registry match.
Form and route. Subcutaneous injection from a prefilled syringe, once or twice daily
Interval reported. Not recorded in this summary
Written into the record, not signed off as a reviewed claim.
Death, myocardial infarction or recurrent angina at 14 days, enoxaparin versus intravenous unfractionated heparin in unstable angina or non-Q-wave myocardial infarction
✓ The study showed what it set out to show
Who was studied
ESSENCE
How many people
3171
Study design
Phase 3 randomised double-blind trial, 48 hours to 8 days of treatment
Compared against
Not recorded for this study
Kind of result
Living longer, or avoiding a major event
What was found
16.6% vs 19.8% at 14 days, p=0.019; 19.8% vs 23.3% at 30 days, p=0.016
Repeated elsewhere
Replicated
What this does not prove. Meeting one endpoint in one population does not carry to other goals or other people.
The limits of this study, and where it came from
Main limit. Bleeding of any kind was significantly higher on enoxaparin, 18.4% against 14.2%, p=0.001, though major bleeding was not (6.5% against 7.0%). The excess was attributed mainly to injection-site ecchymoses.
How far it carries. This study is recorded from the curated record, not from the registry match.
Form and route. Subcutaneous injection from a prefilled syringe, once or twice daily
Interval reported. Not recorded in this summary
Written into the record, not signed off as a reviewed claim.
RNAWiki holds 5 written-up human studies for this substance, each with the question it asked.
How we know it
Each card names the study, the number of people and what the study set out to measure.
What this does not prove
These summaries were written by a person and have not been signed off as reviewed claims.
Why it matters
A study that failed is as informative as one that worked, and both are here.
What we still do not know
No reviewed claim exists, so no exact population, effect size or interval is published yet.
What it changes in the body◇Read from sources, not yet reviewed
The path through the body
From what a person takes to what changes. A solid line is a step measured in people. A dashed line is a step nobody has measured that way.
Start
Enoxaparin
What a person takes: Subcutaneous injection from a prefilled syringe, once or twice daily.
The measurement behind this step
Preservative-free prefilled syringes at 100 mg/mL and 150 mg/mL concentrations, injected into subcutaneous tissue of the abdomen or thigh. An intravenous bolus is used at the start of treatment in ST-elevation myocardial infarction. Peak anti-factor Xa activity occurs 3 to 5 hours after subcutaneous injection, and no routine coagulation monitoring is required in most patients — the practical property that displaced continuous unfractionated heparin infusions from most wards.
Getting in
A fixed injection under the skin, sized by body weight
Given as a small injection into the fat of the abdomen or thigh rather than as a drip. The dose is worked out from body weight and, in most people, needs no blood test to check.
──Measured in people. Written by a person from the study named beside the step. Not signed off as a reviewed claim.
The measurement behind this step
Subcutaneous administration with peak anti-factor Xa activity 3 to 5 hours after injection. Weight-based dosing is possible because the shortened chains bind far less to plasma proteins, endothelium and macrophages than full-length heparin does, which is what makes the response predictable. The activated partial thromboplastin time is prolonged only modestly, up to about 1.8 times control, and is not the assay that reads this drug.
It finds the body’s own brake on clotting, floating in the blood
It never enters a cell. It works entirely in the bloodstream, by finding a protein already circulating there called antithrombin.
╌╌Described, with no measurement named. No measurement is named for this step, so it is drawn as an unconfirmed link.
The measurement behind this step
Enoxaparin is a polydisperse mixture with an average molecular weight of about 4500 daltons. Only the fraction of chains carrying the specific antithrombin-binding pentasaccharide sequence is pharmacologically active; the rest is inert. There is no cellular uptake, no receptor and no intracellular target anywhere in this mechanism.
Antithrombin normally disables clotting enzymes slowly. When enoxaparin binds it, it changes shape and does the same job hundreds of times faster.
╌╌Described, with no measurement named. No measurement is named for this step, so it is drawn as an unconfirmed link.
The measurement behind this step
The pentasaccharide induces a conformational change in antithrombin III that expels its reactive centre loop, converting a slow substrate-like inhibitor into a rapid one. The rate of factor Xa inactivation rises by roughly three orders of magnitude. Enoxaparin itself is not consumed — it dissociates and binds another antithrombin molecule, which is why a small molar quantity has a large effect.
Because the chains are short, most of them can only help attack the upstream enzyme, not the final one. That selectivity is what separates this drug from old-fashioned heparin.
╌╌Described, with no measurement named. No measurement is named for this step, so it is drawn as an unconfirmed link.
The measurement behind this step
Inactivating factor Xa needs only the pentasaccharide. Inactivating thrombin needs a chain long enough — roughly 18 saccharide units — to bridge antithrombin and thrombin simultaneously in a ternary complex. With an average of about 4500 daltons, most enoxaparin chains are too short. The label quantifies the consequence: anti-factor Xa to anti-factor IIa ratio 14.0 ± 3.1, against 1.22 ± 0.13 for unfractionated heparin.
Fewer clots, more bruising, and a kidney-dependent exit
Fewer repeat heart attacks and fewer leg clots, at the cost of more bleeding. The drug leaves through the kidneys, so poor kidney function makes it accumulate.
╌╌Described, with no measurement named. No measurement is named for this step, so it is drawn as an unconfirmed link.
The measurement behind this step
In ExTRACT-TIMI 25, death or nonfatal reinfarction 9.9% against 12.0% on unfractionated heparin, with major bleeding 2.1% against 1.4%. Clearance is predominantly renal, so exposure rises as creatinine clearance falls and the label carries a dose adjustment below 30 mL/min. Protamine sulfate neutralises the anti-factor IIa activity essentially completely but reverses only about 60% of the anti-factor Xa activity — reversal here is partial, unlike with unfractionated heparin.
No suggested links are held for this record, so nothing is hidden from this path.
What we know
The record describes 5 steps from taking it to an effect in a person.
How we know it
Each step names the study behind it in the technical detail beside it.
What this does not prove
A change inside the body is a reason to look. It is not a result in a person.
Why it matters
A reader can see exactly where the chain stops being measured in people.
What we still do not know
No reviewed claim binds any of these steps to a named population.
What is missing or unclear◇Read from sources, not yet reviewed
Were people like you studied?
RNAWiki cannot tell whether a study fits you. It can show who was in it, and where the result stops carrying.
Who was studied
People similar to this profile were included.
Surgical and medical inpatients at risk of leg clots, people being treated for an existing clot, and people having a heart attack. It is one of the most widely administered injectable drugs in hospital medicine, with 111 separate generic products listed in the United States acquisition-cost file.
Who is missing from the studies
Which groups were under-represented in the studies has not been recorded for this substance. Pregnancy, breastfeeding, children, older adults, and people with liver or kidney conditions are commonly excluded from trials; nothing here says whether they were.
What the label states about particular groups
On pediatric, the label states: “Safety and effectiveness of enoxaparin sodium injection in pediatric patients have not been established.”
US prescribing information · 7fa78f8d-92d9-434a-8e26-b886ab0ae77f · read 2026-08-30
On older people, the label states: “Prevention of Deep Vein Thrombosis in Hip, Knee and Abdominal Surgery;”
US prescribing information · 7fa78f8d-92d9-434a-8e26-b886ab0ae77f · read 2026-08-30
On people who are pregnant, the label states: “Risk Summary Placental transfer of enoxaparin was observed in the animal studies.”
US prescribing information · 7fa78f8d-92d9-434a-8e26-b886ab0ae77f · read 2026-08-30
On people who are breastfeeding, the label states: “Risk Summary It is unknown whether enoxaparin sodium injection is excreted in human milk.”
US prescribing information · 7fa78f8d-92d9-434a-8e26-b886ab0ae77f · read 2026-08-30
On people with reduced kidney function, the label states: “In patients with renal impairment, there is an increase in exposure of enoxaparin sodium injection.”
US prescribing information · 7fa78f8d-92d9-434a-8e26-b886ab0ae77f · read 2026-08-30
Where the result stopped carrying
Superiority over unfractionated heparin in SYNERGY, with a significant excess of TIMI major bleeding
The safety comparison against fondaparinux in OASIS-5, where major bleeding was twice as high and 30-day mortality significantly worse
The mortality component of ExTRACT-TIMI 25, p=0.11
Its position as the default after fracture, displaced in 2023 by a 12,211-patient non-inferiority trial of aspirin
This is a scope explorer, not a diagnosis engine.
It shows who was studied so you can see whether people similar to you were included.
RNAWiki cannot tell whether a study fits you. It can show who was in it.
What it would be like to take◇Read from sources, not yet reviewed
Why it might seem to do nothing
A real effect and a noticed effect are different things. These are the recorded reasons the two come apart.
It was studied in different people
The people in the studies were not much like the reader.
On this record: Which groups were under-represented in the studies has not been recorded for this substance. Pregnancy, breastfeeding, children, older adults, and people with liver or kidney conditions are commonly excluded from trials; nothing here says whether they were.
The evidence may simply be wrong
Small early studies often do not hold up.
On this record: RNAWiki has not yet published a reviewed conclusion for this use.
Other reasons RNAWiki checked and found nothing for (11)
It was studied for a different goal
The studies measured something else entirely. Nothing in this record points to this reason.
A different form was studied
The studied form is not the form on the shelf. Nothing in this record points to this reason.
There was nothing to correct
Where a level is already normal, topping it up may change nothing. Nothing in this record points to this reason.
Something else had to happen too
In the studies it was paired with training, a diet or another treatment. Nothing in this record points to this reason.
The change is too small to feel
A real change can still sit below what a person notices. Nothing in this record points to this reason.
Day-to-day swing hides it
Sleep, food, stress and time of day move most numbers more than this would. Nothing in this record points to this reason.
Not enough time yet
The studies ran longer than the person has waited. Nothing in this record points to this reason.
It was not taken as studied
Missed days change the result, and studies count them. Nothing in this record points to this reason.
Something else changed at the same time
Two changes at once cannot be told apart afterwards. Nothing in this record points to this reason.
The product may not be what it says
Contents of a sold product are not always what the label states. Nothing in this record points to this reason.
No recorded reason
RNAWiki has nothing stored that would explain it. Nothing in this record points to this reason.
None of these is a reason to take more. Taking more is not a step this page ever suggests.
What it would be like to take◇Read from sources, not yet reviewed
What taking it involves
The recorded facts about getting hold of it and using it. Nothing here is a suggestion about what you should do.
How it is supplied
Given by a clinician
❝ Quoted from a source
Where this came from
Copied from a source RNAWiki stored, with the source named.
Read from the recorded approval status.
No source is stored against this line.
Form and route
Subcutaneous injection from a prefilled syringe, once or twice daily
✎ Source-linked record
Where this came from
A person wrote this into the record with the study named beside it. No reviewer has signed it off.
The form and route recorded on this substance.
No source is stored against this line.
Who oversees it
Professional supervision is normally required. A regulator classifies this substance in a way that restricts how it is supplied.
❝ Quoted from a source
Where this came from
Copied from a source RNAWiki stored, with the source named.
Suppression classes recorded: S1.
No source is stored against this line.
What is in the pack
Preservative-free prefilled syringes at 100 mg/mL and 150 mg/mL concentrations, injected into subcutaneous tissue of the abdomen or thigh. An intravenous bolus is used at the start of treatment in ST-elevation myocardial infarction.
✎ Source-linked record
Where this came from
A person wrote this into the record with the study named beside it. No reviewer has signed it off.
Recorded notes on how this is sold. The rest of the recorded wording: Peak anti-factor Xa activity occurs 3 to 5 hours after subcutaneous injection, and no routine coagulation monitoring is required in most patients — the practical property that displaced continuous unfractionated heparin infusions from most wards.
No source is stored against this line.
Where it is registered
Regulatory records are listed in the technical disclosure at the foot of this page.
# Counted from records
Where this came from
A count of rows RNAWiki holds. It describes our records, not your body.
Register entries are stored per jurisdiction and shown with their dates.
No source is stored against this line.
Why people stop
Not recorded.
∅ Nothing recorded
Where this came from
RNAWiki holds nothing here and says so rather than guessing.
No record of why people stopped taking it is stored for this substance.
No source is stored against this line.
What it would be like to take◇Read from sources, not yet reviewed
What can go wrong
Sorted by where each line came from. A regulator's label and a report somebody sent in are not the same kind of fact.
·Worth asking a clinician aboutWritten into the record from the studies named on this page
The United States label carries a boxed warning on spinal and epidural haematoma in patients receiving neuraxial anaesthesia or undergoing spinal puncture, which can cause long-term or permanent paralysis, and which applies across the low molecular weight heparin class. Clearance is predominantly renal, so exposure and bleeding risk rise as kidney function falls. Injection-site bruising is common and is not the same event as major bleeding. Heparin-induced thrombocytopenia is much rarer than with unfractionated heparin but not absent, and enoxaparin is contraindicated once that diagnosis is established because the antibody cross-reacts. Protamine sulfate provides only partial reversal.
Nobody counted how many people took this and were fine, so this cannot be turned into a rate.
Over a long time. No completed tested study window is recorded, so long-term effects are not established by the registry record.
Groups the studies covered thinly. Which groups were under-represented in the studies has not been recorded for this substance. Pregnancy, breastfeeding, children, older adults, and people with liver or kidney conditions are commonly excluded from trials; nothing here says whether they were.
What is missing or unclear◇Read from sources, not yet reviewed
Does the exact form matter?
Evidence belongs to the exact thing that was tested. A different salt, a different mixture or a different preparation is a different question.
The form that was studied
Subcutaneous injection from a prefilled syringe, once or twice daily
✎ Source-linked record
Where this came from
A person wrote this into the record with the study named beside it. No reviewer has signed it off.
The form used in the studies cited on this page.
No source is stored against this line.
What is sold
An intravenous bolus is used at the start of treatment in ST-elevation myocardial infarction.
✎ Source-linked record
Where this came from
A person wrote this into the record with the study named beside it. No reviewer has signed it off.
Recorded notes on which forms are sold. The rest of the recorded wording: Peak anti-factor Xa activity occurs 3 to 5 hours after subcutaneous injection, and no routine coagulation monitoring is required in most patients — the practical property that displaced continuous unfractionated heparin infusions from most wards.
No source is stored against this line.
What is recorded as being sold
172 products list this as an active ingredient in the United States drug directory. 172 of them contain it and nothing else.
FDA National Drug Code directory · 0548-5605 · read 2026-08-29
They are sold as injection, injection, solution and powder, taken intravenous and subcutaneous.
FDA National Drug Code directory · 0548-5605 · read 2026-08-29
The regulator's established pharmacologic class for it is heparin, low molecular weight heparin [epc] and low-molecular-weight [cs].
FDA National Drug Code directory · 0548-5605 · read 2026-08-29
29 published labels name it as an active ingredient. 29 of them describe this substance alone, which is where its own label text on this page comes from.
US prescribing information · 7fa78f8d-92d9-434a-8e26-b886ab0ae77f · read 2026-08-29
Those labels are classed as human prescription drug.
US prescribing information · 7fa78f8d-92d9-434a-8e26-b886ab0ae77f · read 2026-08-29
enoxaparin sodium is subcutaneous at 3 DOSAGE FORMS AND STRENGTHS Enoxaparin sodium injection, USP is a clear, colorless to pale-yellow solution available in two concentrations. 100 mg/mL Concentration - Single-Dose Prefilled Syringes 30 mg/0.3 mL, 40 mg/0…, recorded as fda label in effect 2026-01-14 in the United States.
US prescribing information · 7fa78f8d-92d9-434a-8e26-b886ab0ae77f · read 2026-08-30
Recorded price in US: 6.59327–10.89239 USD per one millilitre, across 107 priced products whose strengths and pack forms differ, as of 2026-08-26, paid by retail pharmacies buying the product, as surveyed by the Centers for Medicare & Medicaid Services. It is not a list price, an insurance price, or what anyone pays at a counter..
Recorded source · 2026-08-26 · read 2026-08-28
Evidence carries across two names for one substance. It does not carry across a salt, a mirror form or a mixture.
What it would be like to take◇Read from sources, not yet reviewed
What you could measure
This one is decided with a clinician, so this section holds questions to ask rather than a plan to run.
Self-experiment planning is not offered for a prescription or clinician-supervised medicine. The questions below are for a clinician or pharmacist.
Questions worth asking
Which of the trials of Enoxaparin studied people like me?
What was measured, and for how long?
Was the result a laboratory value or a health outcome?
What would we watch for, and when would we stop?
Tracking can show whether something changed for you. It cannot show what caused it.
RNAWiki records evidence. It does not say whether this substance is right for you.
What is missing or unclear◇Read from sources, not yet reviewed
Claims that go past the evidence
Things said about this substance that sound reasonable, and the exact step that is missing between the evidence and the claim.
✗Goes past the evidence
That enoxaparin reduces mortality after fibrinolysis — death alone was 6.9% against 7.5%, p=0.11, and the composite moved on reinfarction
Why it sounds right. It follows from something real on this page: a body step, an animal result or a related finding.
The missing step. Nobody measured this in people for this use, or the study that did measure it did not show it.
What would change this
A study in people, for this exact use, measuring this exact thing, that a reviewer signs off.
RNAWiki has not yet published a reviewed conclusion for this use.
✗Goes past the evidence
That the advantage over unfractionated heparin generalises across settings — it did not survive an early invasive strategy in SYNERGY
Why it sounds right. It follows from something real on this page: a body step, an animal result or a related finding.
The missing step. Nobody measured this in people for this use, or the study that did measure it did not show it.
What would change this
A study in people, for this exact use, measuring this exact thing, that a reviewer signs off.
RNAWiki has not yet published a reviewed conclusion for this use.
✗Goes past the evidence
That the low molecular weight heparins are interchangeable with one another — each is defined by its own depolymerisation chemistry, and enoxaparin has never been compared head to head with dalteparin in a large outcome trial
Why it sounds right. It follows from something real on this page: a body step, an animal result or a related finding.
The missing step. Nobody measured this in people for this use, or the study that did measure it did not show it.
What would change this
A study in people, for this exact use, measuring this exact thing, that a reviewer signs off.
RNAWiki has not yet published a reviewed conclusion for this use.
✗Goes past the evidence
That generic enoxaparin is clinically equivalent to the innovator — a reasoned inference from five analytical criteria, never tested against a clinical outcome
Why it sounds right. It follows from something real on this page: a body step, an animal result or a related finding.
The missing step. Nobody measured this in people for this use, or the study that did measure it did not show it.
What would change this
A study in people, for this exact use, measuring this exact thing, that a reviewer signs off.
RNAWiki has not yet published a reviewed conclusion for this use.
✗Goes past the evidence
That protamine reverses it — protamine neutralises the anti-factor IIa activity but only about 60% of the anti-factor Xa activity
Why it sounds right. It follows from something real on this page: a body step, an animal result or a related finding.
The missing step. Nobody measured this in people for this use, or the study that did measure it did not show it.
What would change this
A study in people, for this exact use, measuring this exact thing, that a reviewer signs off.
RNAWiki has not yet published a reviewed conclusion for this use.
What is missing or unclear◇Read from sources, not yet reviewed
What nobody knows yet
Open questions, each with why it is open and what would close it.
Missing populations
Which groups were under-represented in the studies has not been recorded.
Why it matters. Recorded by the evidence model as a gap on this record.
What would answer it
A study that measures it, and a reviewer to sign it off.
Last checked 2026-09-04. Searched: The sources listed in the receipts at the foot of this page.
Missing long-term data
No completed tested study window is recorded.
Why it matters. Recorded by the evidence model as a gap on this record.
What would answer it
A study that measures it, and a reviewer to sign it off.
Last checked 2026-09-04. Searched: The sources listed in the receipts at the foot of this page.
No reviewed conclusion
RNAWiki has not yet published a reviewed conclusion for this use.
Why it matters. Recorded by the evidence model as a gap on this record.
What would answer it
A study that measures it, and a reviewer to sign it off.
Last checked 2026-09-04. Searched: The sources listed in the receipts at the foot of this page.
Missing interaction studies
No interaction was found in the registers checked. Not finding one is not the same as showing there is none.
Why it matters. Recorded by the evidence model as a gap on this record.
What would answer it
A study that measures it, and a reviewer to sign it off.
Last checked 2026-09-04. Searched: The sources listed in the receipts at the foot of this page.
Formulation uncertainty
Several salts, forms or products of Enoxaparin are recorded. Results from one form may not transfer to another.
Why it matters. Recorded by the evidence model as a gap on this record.
What would answer it
A study that measures it, and a reviewer to sign it off.
Last checked 2026-09-04. Searched: The sources listed in the receipts at the foot of this page.
Mechanism not reviewed
No reviewed mechanism story exists for this substance.
Why it matters. Recorded by the evidence model as a gap on this record.
What would answer it
A study that measures it, and a reviewer to sign it off.
Last checked 2026-09-04. Searched: The sources listed in the receipts at the foot of this page.
What happened in people◇Read from sources, not yet reviewed
Check any of this yourself
Every line above traced back to the study it came from. This is the technical layer, and the vocabulary changes here.
Every line above can be traced to the study named beside it. Follow the link and read it.
ExTRACT-TIMI 25: death or reinfarction fell from 12.0% to 9.9% in 20,506 patients
In plain words
In people having a heart attack treated with clot-dissolving drugs, enoxaparin given for the whole hospital stay beat two days of standard heparin. About one in six of the bad outcomes was prevented.
What was measured
Death or nonfatal recurrent myocardial infarction through 30 days
Effect estimate
No reviewed effect estimate exists for this record.
Limits
See the technical detail.
From the source
ExTRACT-TIMI 25 (NCT00077792) randomised 20,506 patients with ST-elevation myocardial infarction scheduled for fibrinolysis to enoxaparin throughout the index hospitalisation or weight-based unfractionated heparin for at least 48 hours. Death or nonfatal recurrent myocardial infarction through 30 days occurred in 12.0% on unfractionated heparin against 9.9% on enoxaparin, a 17% relative risk reduction, p<0.001. The composite of death, nonfatal reinfarction or urgent revascularisation was 14.5% against 11.7%, p<0.001, and the net clinical benefit composite of death, nonfatal reinfarction or nonfatal intracranial haemorrhage was 12.2% against 10.1%, p<0.001. This is the largest and cleanest positive trial enoxaparin has.
Written into the record, not signed off as a reviewed claim
The mortality half of that composite did not move
In plain words
The headline benefit came almost entirely from fewer repeat heart attacks, not from fewer deaths. Deaths alone were 6.9% against 7.5%, a difference that could easily be chance.
What was measured
Death alone at 30 days, 6.9% against 7.5%, p=0.11; nonfatal reinfarction 3.0% against 4.5%, p<0.001; major bleeding 2.1% against 1.4%, p<0.001
Effect estimate
No reviewed effect estimate exists for this record.
Limits
See the technical detail.
From the source
Decomposing the ExTRACT-TIMI 25 primary endpoint: nonfatal reinfarction occurred in 4.5% of unfractionated heparin patients against 3.0% of enoxaparin patients, a 33% relative risk reduction, p<0.001. Death occurred in 7.5% against 6.9%, p=0.11. A composite endpoint made of one component that moved a third and another that did not move significantly is a legitimate primary endpoint and a misleading headline, and "enoxaparin saves lives after a heart attack" is not what this trial measured. The trial is also honest about its price: major bleeding was 2.1% on enoxaparin against 1.4% on unfractionated heparin, p<0.001, which is a 50% relative increase.
Written into the record, not signed off as a reviewed claim
SYNERGY: no advantage over plain heparin when patients went early to the catheter lab
In plain words
In 10,027 high-risk patients taken quickly for angiography, enoxaparin was no better than ordinary heparin at preventing death or heart attack, and caused significantly more serious bleeding.
What was measured
Death or nonfatal myocardial infarction at 30 days, and TIMI major bleeding, in an early invasive strategy
Effect estimate
No reviewed effect estimate exists for this record.
Limits
This entry records a failure.
From the source
SYNERGY was an open-label randomised trial in 10,027 high-risk non-ST-elevation acute coronary syndrome patients managed with an intended early invasive strategy. Death or nonfatal myocardial infarction at 30 days occurred in 14.0% (696 of 4,993) on enoxaparin against 14.5% (722 of 4,985) on unfractionated heparin, odds ratio 0.96 (95% CI 0.86 to 1.06) — non-inferior, not superior. Procedural outcomes were indistinguishable: abrupt closure 1.3% against 1.7%, unsuccessful percutaneous coronary intervention 3.6% against 3.4%. TIMI major bleeding was significantly higher on enoxaparin, 9.1% against 7.6%, p=0.008, with a non-significant excess in GUSTO severe bleeding (2.7% against 2.2%, p=0.08). The authors’ own conclusion states that the convenience advantage "should be balanced with the modest excess of major bleeding".
Written into the record, not signed off as a reviewed claim
OASIS-5: fondaparinux halved major bleeding against it, and fewer patients died
In plain words
The largest trial ever to compare enoxaparin with another anticoagulant found the same number of heart attacks and half the serious bleeds on the competitor — and fewer deaths at a month.
What was measured
Major bleeding at nine days, 4.1% on enoxaparin against 2.2% on fondaparinux, and 30-day mortality 352 against 295
Effect estimate
No reviewed effect estimate exists for this record.
Limits
This entry records a failure.
From the source
OASIS-5 (NCT00139815) randomised 20,078 acute coronary syndrome patients to fondaparinux 2.5 mg daily or enoxaparin 1 mg/kg twice daily for a mean of six days. Death, myocardial infarction or refractory ischaemia at nine days occurred in 5.8% on fondaparinux against 5.7% on enoxaparin (hazard ratio 1.01, 95% CI 0.90 to 1.13) — a tie meeting non-inferiority. Major bleeding at nine days was 2.2% against 4.1% (hazard ratio 0.52, p<0.001). The combination of the primary outcome and major bleeding favoured fondaparinux, 7.3% against 9.0% (hazard ratio 0.81, p<0.001). Deaths at 30 days were 295 against 352, p=0.02, and at 180 days 574 against 638, p=0.05. This is enoxaparin losing a fair fight on safety in the largest randomised comparison it has been in.
Written into the record, not signed off as a reviewed claim
PREVENT CLOT: twice-daily aspirin was non-inferior after a fracture
In plain words
Guidelines had recommended injected heparin after fractures for years. A 12,211-patient trial in 2023 found that two cheap aspirin tablets a day prevented death just as well, though slightly more leg clots occurred.
What was measured
Death from any cause at 90 days, and deep vein thrombosis, after operatively treated fracture
Effect estimate
No reviewed effect estimate exists for this record.
Limits
See the technical detail.
From the source
PREVENT CLOT (NCT02984384) was a pragmatic randomised non-inferiority trial in 12,211 patients aged 18 or over with an operatively treated extremity fracture or any pelvic or acetabular fracture, assigned to enoxaparin 30 mg twice daily or aspirin 81 mg twice daily in hospital. Death from any cause at 90 days occurred in 47 aspirin patients (0.78%) against 45 enoxaparin patients (0.73%), difference 0.05 percentage points, 96.2% CI -0.27 to 0.38, p<0.001 against a non-inferiority margin of 0.75 points. Deep vein thrombosis was higher on aspirin, 2.51% against 1.71%, difference 0.80 points (95% CI 0.28 to 1.31); pulmonary embolism was identical at 1.49% in each group, and bleeding complications were similar. The field’s conclusion moved from "low molecular weight heparin is the standard after fracture" to "aspirin is a defensible choice", on a trial whose primary endpoint was death rather than clot — which is exactly the caveat the result carries.
Written into the record, not signed off as a reviewed claim
Heparin-induced thrombocytopenia is roughly thirteen times rarer than with plain heparin
In plain words
Heparins can trigger an immune reaction that destroys platelets and paradoxically causes clots. It happens far less often with enoxaparin than with older heparin — about 1 patient in 500 rather than 1 in 40.
What was measured
Absolute risk of heparin-induced thrombocytopenia, 0.2% with low molecular weight heparin against 2.6% with unfractionated heparin
Effect estimate
No reviewed effect estimate exists for this record.
Limits
See the technical detail.
From the source
A meta-analysis of 15 studies in 7,287 thromboprophylaxis patients compared heparin-induced thrombocytopenia rates between unfractionated heparin and low molecular weight heparin, defining the condition as a platelet fall below 50% or below 100 × 10^9/L together with a positive laboratory assay. Two randomised trials measuring heparin-induced thrombocytopenia gave an odds ratio of 0.10 (95% CI 0.01 to 0.2, p=0.03) favouring low molecular weight heparin, and three prospective studies gave the same 0.10 (95% CI 0.03 to 0.33, p<0.001). The inverse variance-weighted absolute risk was 0.2% with low molecular weight heparin against 2.6% with unfractionated heparin. Two limits belong on this: most of the included patients were orthopaedic surgical patients, and lower is not zero — enoxaparin remains contraindicated in a patient with established heparin-induced thrombocytopenia, because the antibody cross-reacts.
Written into the record, not signed off as a reviewed claim
The generics were approved as "the same" without a single clinical outcome trial
In plain words
Enoxaparin is not one molecule but thousands of different sugar chains. In 2010 the FDA decided a copy could be called identical on laboratory characterisation alone, with no trial in patients.
What was measured
That physicochemical and pharmacodynamic equivalence establishes clinical equivalence for a polydisperse, animal-derived mixture — a reasoned regulatory inference, never tested against a clinical outcome
Effect estimate
No reviewed effect estimate exists for this record.
Limits
See the technical detail.
From the source
The FDA approved the first generic enoxaparin in July 2010 through the abbreviated new drug application pathway, requiring five criteria of sameness rather than a clinical endpoint study: equivalence of physicochemical properties; equivalence of heparin source material and mode of depolymerisation; equivalence of disaccharide building blocks, fragment mapping and sequence of oligosaccharide species; equivalence of biological and biochemical assays; and equivalence of in vivo pharmacodynamic profile. The agency published its reasoning in Nature Biotechnology in 2013. The scientific case is serious and the inference is still an inference: the argument is that a sufficiently complete structural and pharmacodynamic fingerprint implies clinical equivalence, and that implication was never tested against an outcome. The counter-argument — that a polydisperse animal-derived mixture may carry clinically relevant properties not captured by any current assay — is the same argument, run in the opposite direction, and it is also untested.
Written into the record, not signed off as a reviewed claim
ESSENCE, 1997: the trial that started it, and the bleeding it did and did not cause
In plain words
The original trial found fewer heart events on enoxaparin than on standard heparin. Serious bleeding was not increased; visible bruising at the injection sites was, substantially.
What was measured
Composite of death, myocardial infarction or recurrent angina at 14 and 30 days, and major versus any bleeding
Effect estimate
No reviewed effect estimate exists for this record.
Limits
See the technical detail.
From the source
ESSENCE randomised 3,171 patients with rest angina or non-Q-wave myocardial infarction to enoxaparin 1 mg/kg subcutaneously twice daily or continuous intravenous unfractionated heparin, for 48 hours to 8 days. Death, myocardial infarction or recurrent angina occurred in 16.6% against 19.8% at 14 days (p=0.019) and 19.8% against 23.3% at 30 days (p=0.016), with revascularisation at 30 days 27.1% against 32.2% (p=0.001). Major bleeding at 30 days was 6.5% against 7.0% — no significant difference — while bleeding of any kind was 18.4% against 14.2% (p=0.001), attributed primarily to injection-site ecchymoses. The distinction between those two bleeding numbers is the whole of what a patient needs to understand about this drug’s visible side effect.
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What is not here
7 questions this page could not answer
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How close this is to real life — found nothing in the sources checked.
Felt, measured, or meaningful — found nothing in the sources checked.
How long anything takes — found nothing in the sources checked.
What it may clash with — found nothing in the sources checked.
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The record as stored
The full record, for auditing
Everything above is built from what is below. This layer keeps the technical vocabulary, record identifiers and every stored row, so a reader who wants to check the page can.
The older medicine-wide conclusion held in this record
Written for a clinical reader, and about the medicine as a whole rather than about one indication, population and set of trials. RNAWiki does not treat it as a programme conclusion and no reviewer has signed it off in that form. It is here word for word because it is what the record holds.
A chemically shortened heparin, given as a fixed weight-based injection instead of a monitored infusion, which cut death or reinfarction from 12.0% to 9.9% in 20,506 heart attack patients — a result driven by reinfarction rather than by death, and bought with more major bleeding, 2.1% against 1.4%.
Recorded evidence blocks (9)
Q2
On the Enoxaparin label: indicated for what?
"Lovenox is a low molecular weight heparin (LMWH) indicated for: Prophylaxis of deep vein thrombosis (DVT) in abdominal surgery, hip replacement surgery, knee replacement surgery, or medical patients with severely restricted mobility during acute illness ( 1.1 ) Inpatient treatment of acute DVT with or without…": indications and usage on Enoxaparin's label. DailyMed label · 5017a927-2a24-4f27-89f9-27c805bf7d59 · 2026-05-28
Q3
278 registered trials of Enoxaparin — at which phases?
Registered studies posting no result
207 of 278
278 registered studies of Enoxaparin: 95 phase3, 69 phase2, 63 phase4, 35 na, 19 phase1, 13 na or unstated, 2 early phase1. CLINICALTRIALS_SNAPSHOT · 2026-09-01
994 with a PubMed record
Show the evidence
phase3
95
phase2
69
phase4
63
na
35
phase1
19
na or unstated
13
10 more recorded rows
early phase1
2
completed
181
unknown
34
terminated
31
recruiting
13
not yet recruiting
9
withdrawn
6
active not recruiting
2
enrolling by invitation
1
no longer available
1
recorded 2026-09-01 · last checked 2026-09-04
Q4
36 of Enoxaparin's trials stopped: safety, futility/efficacy, accrual/recruitment, funding/business, other?
safety (1), futility/efficacy (3), accrual/recruitment (17), funding/business (2) and other (13): Enoxaparin's stop wording, clustered. CLINICALTRIALS_SNAPSHOT · 2026-09-01
"Inadequate number of eligible patients"; 36 of 293 registered studies
Show the evidence
Trial
NCT00426127
terminated; "Inadequate number of eligible patients"
NCT00493896
terminated; "low enrollment"
NCT00518245
terminated; "Low rate of patient recruitment. Cannot achieve sample size."
NCT00521885
terminated; "Study stopped due to lack of accrual"
NCT00633061
terminated; "Futility; unable to complete screening due to clinical practice change"
NCT00769873
terminated; "Recruitment was slower than anticipated. Insufficient funding to expand to multi-centered trial."
14 further recorded trials
NCT00836355
terminated; "Too few acute stroke patients available to meet enrollment requirements."
NCT00916669
withdrawn; "sponsor withdrew funding prior to patient enrollment"
NCT01058759
terminated; "The external funding (pharmaceutical company) was stopped and could not be substituded by internal funding."
NCT01164046
terminated; "Due to slow inclusion of patients"
NCT01325779
withdrawn; "poor enrollment"
NCT01356992
terminated; "Change in strategy regarding the product by the company"
NCT01474902
withdrawn; "Poor enrollment"
NCT01573169
terminated; "The trial has been terminated prematurely after the randomization of 73 patients due to a lack of funding."
NCT01817257
terminated; "Early findings showed trial was not feasible"
NCT01965002
terminated; "Accrual factor"
NCT02396732
terminated; "Terminated due to futility and less subjects meeting entry criteria"
NCT02401594
terminated; "Remaining outdated treatments and additional costs too high for new manufacturing"
NCT02589145
terminated; "Closed due to very slow accrual"
NCT02744833
terminated; "The trial was funded in part by a grant; the trial closed when the grant ended."
recorded 2026-09-01 · last checked 2026-09-04
Q5
Human studies of Enoxaparin used Enoxaparin 0.5 mg/kg once daily — over how long?
studies of Enoxaparin used the recorded amount. ClinicalTrials.gov · 2026-09-01
15 recorded entries; human; also "Enoxaparin 0.5 mg/kg once daily", "Enoxaparin sodium 20mg", "Enoxaparin sodium 20 mg (=2000IU)"
Show the evidence
human
NCT00585182
Enoxaparin 0.5 mg/kg once daily
NCT01181141
Enoxaparin sodium 20mg
NCT01203098
Enoxaparin sodium 20 mg (=2000IU)
NCT01970202
40mg Enoxaparin
NCT01970202
60mg Enoxaparin
NCT02342444
Enoxaparin Sodium Injection 30 mg BID
9 more recorded rows
humanNCT02342444
Enoxaparin Sodium Injection 40 mg QD
humanNCT02444572
Enoxaparin 4000 IU
humanNCT02774265
VTE prophylaxis with Enoxaparin 30mg BID
humanNCT03081169
Enoxaparin Sodium 150 MG/ML Prefilled Syringe
humanNCT03244020
Enoxaparin 40Mg/0.4mL Prefilled Syringe
humanNCT03891524
Enoxaparin 40 mg
humanNCT04409834
Enoxaparin 1 mg/kg
humanNCT04409834
Enoxaparin 40 mg SC
humanNCT04427098
Enoxaparin 40 Mg/0.4 mL Injectable Solution
recorded 2026-09-01 · last checked 2026-09-04
Q6
Enoxaparin's half-life is 4.5 hours — which schedules were studied?
4.5 hours; Elimination half-life based on anti-Factor Xa activity was 4.5 hours after a single subcutaneous dose to about 7 hours after repeated dosing.
tmaxpharmacokinetics
5 Days; Table 13: Pharmacokinetic Parameters Means ±SD at Day 5 and 90% Confidence Interval (CI) of the ratio After 5 Days of 1.5 mg/kg Subcutaneous Once-Daily Doses of Enoxaparin Sodium Using 100 mg/mL or 200 mg/mL Concentrations Concentration Anti-Xa Anti-IIa Heptest aPTT A max (IU/mL or Δ sec) 100 mg/mL 1.37 (±0.23) 0.23 (±0.05) 105 (±17) 19 (±5) 200 mg/mL 1.45 (±0.22) 0.26 (±0.05) 111 (±17) 22 (±7)…
bioavailabilitypharmacokinetics
100 %; Mean absolute bioavailability of enoxaparin, after 1.5 mg/kg given subcutaneously, based on anti-Factor Xa activity is approximately 100% in healthy subjects.
metabolismpharmacokinetics
Metabolism Enoxaparin sodium is primarily metabolized in the liver by desulfation and/or depolymerization to lower molecular weight species with much reduced biological potency.
recorded 2026-05-28 · last checked 2026-09-04
Q7
Which 117 trials of Enoxaparin posted no result?
Posted no result
117 of 117 completed trials
Registrations
NCT00004875, NCT00839826, NCT00321009, NCT01945879, NCT00398905 and NCT00289042, and 111 more
Completion dates
oldest 1999-03; newest 2024-08-26
Show the evidence
Trial
NCT00004875
1999-03
NCT00839826
2003-11
NCT00321009
2004-04
NCT01945879
2004-04
NCT00398905
2004-09
NCT00289042
2004-11
14 further recorded trials
NCT00074828
2005-05
NCT00420667
2005-05
NCT00396786
2005-07
NCT00170378
2005-08
NCT00077844
2005-09
NCT00097357
2005-12
NCT00139815
2005-12
NCT00298285
2006-10
NCT00077792
2006-12
NCT00790387
2006-12
NCT00253396
2007-01
NCT00361894
2007-01
NCT00077753
2007-02
NCT00329628
2007-03
Q8
At the median, Enoxaparin's trials enrolled 153 people — anything larger?
Median enrolment
153
Largest enrolment
149248
Registered trials counted
289
Q9
What do 8069 spontaneous reports say about Enoxaparin — and not say?
These are reports people sent to a regulator. They do not show the medicine caused the reaction. Nobody counted how many people took the medicine and reported nothing. The same event can be reported more than once, and many reports are incomplete. News coverage, lawsuits and new warnings change how often people report. A count is not a rate and not a risk.
Enoxaparin appears in spontaneous reports to regulators. Across the 10 most-reported reaction terms, 8069 reaction mentions were counted: heparin-induced thrombocytopenia 1425; thrombocytopenia 1223; anaemia 913; haematoma 868. FAERS via Open Targets · CHEMBL1201685 · 2026-06-24
Show the evidence
heparin-induced thrombocytopenia
1425
thrombocytopenia
1223
anaemia
913
haematoma
868
haemorrhage
831
haemoglobin decreased
734
4 more recorded rows
premature baby
559
deep vein thrombosis
544
pulmonary embolism
486
gastrointestinal haemorrhage
486
recorded 2026-06-24 · last checked 2026-09-04
Q10
Which 10 reactions does Enoxaparin's label not list?
ClinicalTrials.gov — US Government work · Open Targets 26.06 — CC0 · mixed register set; per-register licences in docs/specs/corpus-20k-sources.md · openFDA / DailyMed — US Government work
✗ required summary fields resolved: 4 required field(s) not terminal: Why people use it, Best-supported result, Biggest unanswered question, Human evidence
✓ public claims reviewed: 0 reviewed claim(s); drafts are never rendered
✓ source coverage passed: 6 source rows
✓ no critical contamination: no quarantine open
✓ canonical metadata passed: slug and display name present
✓ no raw internal fields: enforced by the copy-contract test over the rendered page
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