Enoxaparin
A low-molecular-weight heparin injected under the skin to prevent and treat deep vein thrombosis and in acute coronary syndromes.
Drug card
- Class
- Heparin
- How it works
- Boosting antithrombin, which then switches off thrombin and factor Xa
- Used for
- Preventing and treating deep vein thrombosis
- Pulmonary embolism (with DVT)
- Unstable angina and heart attack, with aspirin
- Known for
- Bleeding
- Spinal or epidural hematoma, which can paralyze
- Its name
- -parin means a heparin or low-molecular-weight heparin
Study it as a flashcard, and it comes back before you forget it.
Mechanism of action
How does enoxaparin work?
A low-molecular-weight heparin made by breaking pig-derived heparin into shorter chains (about 4,500 daltons on average). It binds and activates antithrombin like heparin, but it acts mainly on factor Xa: its anti-Xa to anti-thrombin ratio is about 14, against about 1 for unfractionated heparin. Almost all of a dose under the skin is absorbed, and the kidneys clear part of it.
Like other heparins: Heparins bind antithrombin (heparin cofactor) and activate it. With unfractionated heparin, antithrombin then inactivates thrombin and factor Xa about equally; the shorter chains of low-molecular-weight heparins steer it mainly against factor Xa. They stop new clots forming and existing ones growing, but they do not dissolve a clot that is already there.
Uses
What is enoxaparin used for?
- Preventing and treating deep vein thrombosis
- Pulmonary embolism (with DVT)
- Unstable angina and heart attack, with aspirin
Side effects
Side effects of enoxaparin
- BleedingKnown forSerious
- Spinal or epidural hematoma, which can paralyzeKnown forSerious
- Heparin-induced thrombocytopenia (HIT)Serious
- Low platelet count
- Anemia
- Raised liver enzymes
- Pain and bruising at the injection site
- Nausea
- Diarrhea
- High potassium (hyperkalemia)Serious
- Osteoporosis with long-term use
- Allergic reactions, itching and hives
Known for marks what an exam expects you to know it for.
Watch for
Cautions and what sets it apart
- Spinal or epidural anesthesia or puncture (boxed warning): a hematoma can cause permanent paralysis, so time doses around the procedure.
- Severe kidney impairment (creatinine clearance under 30 mL/min): exposure rises, so a reduced dose is used.
- Contraindicated with active major bleeding, HIT in the past 100 days, or allergy to heparin or pork products.
- Pregnant women with mechanical heart valves: valve clots have occurred, so anti-Xa levels are checked often.
Good to know: Acts mainly on factor Xa; protamine neutralizes only about 60% of that effect, and HIT and osteoporosis are less common than with unfractionated heparin.
Remember it
A way to remember it
PATHOS
- P
- Protamine reverses them (fully only for unfractionated heparin)
- A
- Antithrombin is the partner they work through
- T
- Thrombocytopenia, including HIT
- H
- Hyperkalemia
- O
- Osteoporosis with long-term use
- S
- Spinal or epidural hematoma
Written for biofideX
Its name
-parin means heparin or low-molecular-weight heparin
Covers heparin itself and low-molecular-weight heparins such as enoxaparin and dalteparin. Fondaparinux, a synthetic factor Xa inhibitor, ends in -parinux.
- Every drug name stem
Its class
Heparins
Other heparins with a card:
Easily mixed up with direct factor Xa inhibitors, direct thrombin inhibitors and vitamin K antagonists.
Sources
Checked against
Written for biofideX in plain words, after checking these references:
- Enoxaparin sodium injection: label (DailyMed)
- Enoxaparin (NCI Thesaurus)
- Low Molecular Weight Heparin (NCI Thesaurus)
For learning pharmacology, not for treatment decisions: no doses are given, and a prescriber, pharmacist or the product's own label is the word on any one patient. Spotted a mistake? Tell us and we'll correct it.
Blood clots and cholesterol
Enoxaparin is one of 19 drugs practiced together here: their classes, how they work, what they treat and what they're known for.
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