Enoxaparin exerts its anticoagulant effect by enhancing the activity of antithrombin III (ATIII), a natural inhibitor of clotting factors. The mechanism of action involves:

1. Inhibition of Factor Xa and Thrombin:
   • Enoxaparin binds to ATIII, causing a conformational change that enhances its ability to inactivate factor Xa and, to a lesser extent, thrombin (factor IIa).
   • By inhibiting these clotting factors, enoxaparin prevents the formation of blood clots.
2. Selective Action:
   • Enoxaparin has a higher ratio of anti-factor Xa to anti-factor IIa activity compared to unfractionated heparin, making it more specific and predictable.
3. Subcutaneous Administration:
   • Enoxaparin is administered subcutaneously, allowing for convenient outpatient use and reduced need for frequent monitoring.

Enoxaparin is approved for the following conditions:

1. Prevention of Venous Thromboembolism (VTE):
   • Used in patients undergoing surgery (e.g., hip or knee replacement) or those at high risk of VTE due to immobility.
2. Treatment of Deep Vein Thrombosis (DVT) and Pulmonary Embolism (PE):
   • Used for the acute treatment of DVT and PE, often in combination with warfarin or other oral anticoagulants.
3. Unstable Angina and Non-ST-Segment Elevation Myocardial Infarction (NSTEMI):
   • Used as part of the management of acute coronary syndromes to prevent further thrombotic events.
4. Prevention of Clotting in Extracorporeal Circuits:
   • Used in patients undergoing hemodialysis or hemofiltration to prevent clotting in the extracorporeal circuit.

The dosage of enoxaparin varies depending on the indication and patient-specific factors. Below are general guidelines:

1. Prevention of VTE:
   • General Surgery: 20–40 mg subcutaneously once daily, starting 2 hours before surgery.
   • Hip or Knee Replacement: 30 mg subcutaneously twice daily or 40 mg once daily, starting 12 hours before surgery.
   • Medical Patients: 40 mg subcutaneously once daily.
2. Treatment of DVT and PE:
   • Standard Dose: 1 mg/kg subcutaneously every 12 hours or 1.5 mg/kg once daily.
   • Duration: Typically 5–10 days, followed by transition to an oral anticoagulant.
3. Unstable Angina and NSTEMI:
   • Standard Dose: 1 mg/kg subcutaneously every 12 hours, in combination with aspirin.
4. Prevention of Clotting in Extracorporeal Circuits:
   • Dose: 1 mg/kg subcutaneously at the start of the procedure, followed by 0.5–1 mg/kg every 4 hours as needed.
5. Special Populations:
   • Renal Impairment: Dose adjustment is required for patients with severe renal impairment (CrCl < 30 mL/min).

Elderly: No dose adjustment is required unless renal function is impaired

Enoxaparin is generally well-tolerated, but some side effects may occur. These include:

1. Common Side Effects:
   • Bleeding (e.g., hematoma at the injection site, nosebleeds)
   • Injection site reactions (e.g., pain, redness, swelling)
   • Anemia
2. Less Common Side Effects:
   • Thrombocytopenia (low platelet count)
   • Elevated liver enzymes
   • Allergic reactions (e.g., rash, itching)
3. Rare but Serious Side Effects:
   • Major Bleeding: Gastrointestinal bleeding, intracranial hemorrhage.
   • Heparin-Induced Thrombocytopenia (HIT): A severe immune-mediated reaction that can lead to thrombosis.

Osteoporosis: With long-term use, especially in high doses

1. Contraindications:
   • Hypersensitivity to enoxaparin, heparin, or pork products.
   • Active major bleeding.
   • History of heparin-induced thrombocytopenia (HIT).
2. Warnings:
   • Bleeding Risk: Enoxaparin increases the risk of bleeding. Use with caution in patients with a history of bleeding disorders or conditions that predispose to bleeding.
   • Renal Impairment: Use with caution in patients with severe renal impairment (CrCl < 30 mL/min). Dose adjustment may be required.
   • Pregnancy and Lactation: Enoxaparin is generally considered safe during pregnancy and breastfeeding, but consult a healthcare provider for risks and benefits.
3. Monitoring:
   • Regular monitoring of platelet counts to detect HIT.
   • Watch for signs of bleeding (e.g., unusual bruising, blood in stool or urine).

Enoxaparin interacts with several medications, including:

1. Other Anticoagulants (e.g., warfarin, heparin): Increased risk of bleeding.
2. Antiplatelet Agents (e.g., aspirin, clopidogrel): Increased risk of bleeding.
3. NSAIDs (e.g., ibuprofen): Increased risk of gastrointestinal bleeding.
4. Thrombolytics (e.g., alteplase): Increased risk of bleeding.

Enoxaparin is available under its generic name as well as brand names. Some common formulations include:

• Generic Name: Enoxaparin sodium
• Brand Names: Lovenox (commonly used in the US and UK), Clexane (commonly used in Europe), and others depending on the region.