Generic Name

Enoxaparin Sodium

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Classification

FDA Approved Indications

• Deep vein thrombosis (DVT) prophylaxis in abdominal surgery, hip or knee replacement, hospitalization for medical illness
• Treatment of DVT with or without pulmonary embolism (PE)
• Prophylaxis of ischemic complications in unstable angina/non-Q wave myocardial infarction (NSTEMI)

Mechanism of Action

Enoxaparin enhances the activity of antithrombin III, which inactivates factor Xa and IIa (thrombin), leading to anticoagulation. It predominantly inhibits factor Xa, reducing thrombin generation and clot formation.

Dosage and Administration

Adult: DVT prophylaxis: 40 mg SC once daily, started 2 hours before surgery or as directed; Treatment of DVT/PE: 1 mg/kg SC every 12 hours or 1.5 mg/kg once daily, with adjustments based on weight and renal function.

Pediatric: Use in children is not well established; consult specific pediatric dosing guidelines.

Geriatric: Adjust dose based on renal function; increased risk of bleeding in elderly.

Renal Impairment: Dose adjustment required based on renal function. Usually, reduce dose or extend dosing interval in patients with renal impairment.

Hepatic Impairment: No specific adjustment required.

Pharmacokinetics

Absorption: Administered subcutaneously; bioavailability approximately 90%.

Distribution: Limited data, but mainly remains within plasma and interstitial fluids.

Metabolism: Metabolized in the liver, with clearance also via the reticuloendothelial system.

Excretion: Primarily excreted unchanged in urine.

Half Life: Approximately 4.5 hours in adults.

Contraindications

• Active major bleeding
• History of heparin-induced thrombocytopenia (HIT)
• Hypersensitivity to enoxaparin or heparins

Precautions

• Use cautiously in patients with bleeding disorders, recent surgery, or trauma
• Monitor for signs of bleeding and thrombocytopenia during therapy

Adverse Reactions - Common

• Bleeding (Common)
• Injection site hematoma or pain (Common)
• Anemia (Less common)

Adverse Reactions - Serious

• Heparin-induced thrombocytopenia (HIT) (Rare)
• Spinal/epidural hematoma leading to paralysis, when used with neuraxial anesthesia (Very rare)

Drug-Drug Interactions

• Other anticoagulants (warfarin, dabigatran, rivaroxaban), antiplatelet agents (aspirin, clopidogrel), NSAIDs

Drug-Food Interactions

• No significant interactions

Drug-Herb Interactions

• Ginger, garlic, ginkgo may increase bleeding risk

Nursing Implications

Patient/Family Teaching

• Instruct patient to report signs of bleeding (unusual bruising, blood in urine/stool, bleeding gums), avoid activities that may cause injury, and inform healthcare providers of all medications including OTC and herbal supplements.

Special Considerations

Black Box Warnings:

• Epidural or spinal hematoma risk in patients receiving neuraxial anesthesia or lumbar puncture

Genetic Factors: No specific genetic factors affecting enoxaparin, but individual variations in metabolism or renal function can impact dosing.

Lab Test Interference: Calibrated for routine coagulation testing; can slightly affect aPTT and INR, but these are not reliable indicators of enoxaparin activity.

Overdose Management

Signs/Symptoms: Excessive bleeding, hematomas, hematuria, blood in stool or vomit, hypotension.

Treatment: Discontinue enoxaparin, apply local pressure for bleeding, transfusions if necessary, and consider administration of protamine sulfate—though it only partially neutralizes enoxaparin.

Storage and Handling

Storage: Store at room temperature between 20°C to 25°C, away from moisture and light.

Stability: Stable until the expiration date; do not freeze or shake the prefilled syringes.