Generic Name: Enoxaparin Sodium
Therapeutic Class: Low Molecular Weight Heparin (Anticoagulant)
Indications
Enoxaparin Sodium is a potent anticoagulant used for the prevention and treatment of thromboembolic disorders:
- Prophylaxis of Venous Thromboembolism (VTE): Prevention of Deep Vein Thrombosis (DVT) in patients undergoing orthopedic (hip/knee replacement) or general surgery, and in acutely ill medical patients with restricted mobility.
- Treatment of Existing VTE: Management of DVT with or without pulmonary embolism (PE).
- Unstable Angina & NSTEMI: Treatment of acute coronary syndromes when administered concurrently with Aspirin.
- Acute STEMI: Treatment of acute ST-segment Elevation Myocardial Infarction, including patients to be managed medically or with subsequent Percutaneous Coronary Intervention (PCI).
- Hemodialysis: Prevention of thrombus formation in the extracorporeal circulation during hemodialysis sessions.
Dosage & Administration
Enoxaparin is administered via Deep Subcutaneous (SC) Injection or Intravenous (IV) Bolus (only for specific MI protocols). It must not be given intramuscularly.
- Prophylaxis in Surgery: Usually 20 mg or 40 mg once daily SC. First dose is typically given 2 hours before surgery.
- Treatment of DVT/PE: 1.5 mg/kg body weight once daily SC or 1 mg/kg twice daily SC.
- Unstable Angina/NSTEMI: 1 mg/kg every 12 hours SC for 2 to 8 days.
- Renal Impairment: For severe renal impairment (Creatinine Clearance < 30 ml/min), the dosage must be adjusted (e.g., 30 mg once daily for VTE prophylaxis).
- Administration: Usually injected into the fatty tissue of the lower abdomen (love handles). Do not expel the air bubble from the pre-filled syringe before injection to avoid loss of drug.
Description & Pharmacokinetics
Enoxaparin is obtained by alkaline depolymerization of heparin benzyl ester derived from porcine intestinal mucosa.
Mechanism of Action: Enoxaparin acts by enhancing the inhibition rate of **Antithrombin III**. It possesses a high **Anti-Xa activity** and low **Anti-IIa (anti-thrombin) activity** (ratio of approx 4:1). By neutralizing Factor Xa, it effectively disrupts the coagulation cascade and prevents the conversion of prothrombin to thrombin, thereby inhibiting fibrin clot formation.
Pharmacokinetics:
Mechanism of Action: Enoxaparin acts by enhancing the inhibition rate of **Antithrombin III**. It possesses a high **Anti-Xa activity** and low **Anti-IIa (anti-thrombin) activity** (ratio of approx 4:1). By neutralizing Factor Xa, it effectively disrupts the coagulation cascade and prevents the conversion of prothrombin to thrombin, thereby inhibiting fibrin clot formation.
Pharmacokinetics:
- Bioavailability: Nearly 100% after subcutaneous injection.
- Peak Activity: Anti-Xa activity reaches its peak 3 to 5 hours after injection.
- Metabolism: Primarily desulfated and depolymerized in the liver to lower molecular weight species.
- Elimination: Excreted mainly via the kidneys. The elimination half-life is about 4.5 to 7 hours.
Side Effects
- Hemorrhage: Major bleeding, including intracranial or retroperitoneal hemorrhage.
- Thrombocytopenia: Moderate (Type I) or severe immune-mediated Heparin-Induced Thrombocytopenia (HIT).
- Local Reactions: Pain, bruising, or hematoma at the injection site.
- Hepatic: Transient increases in liver transaminases (ALT/AST).
- Others: Anemia, fever, and hyperkalemia.
Extra Important Information: Usage Insights
- Monitoring: Routine monitoring of Coagulation (PT/aPTT) is generally not required, unlike unfractionated heparin. However, Anti-Xa levels may be monitored in obese patients, pregnant women, or those with renal failure.
- Rotation of Sites: Always rotate the injection site between the left and right anterolateral and posterolateral abdominal wall to prevent skin issues.
- Spinal/Epidural Anesthesia: There is a risk of spinal hematoma if Enoxaparin is used during spinal/epidural puncture; this can lead to permanent paralysis.
Pregnancy & Lactation
- Pregnancy: Category B. It is the preferred anticoagulant for pregnant women requiring VTE prophylaxis or treatment as it does not cross the placenta.
- Lactation: It is not known whether it is excreted in human milk. However, due to its high molecular weight and poor oral absorption, it is unlikely to affect the nursing infant.
Storage
Store at room temperature (below 25°C). Do not freeze. Store in the original package to protect from light.
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