1. Clinical Overview
Enoxaparin sodium is a low molecular weight heparin (LMWH) derived from porcine intestinal mucosa. It is an anticoagulant that acts by potentiating the inhibition of Factor Xa and thrombin (Factor IIa) by antithrombin III. The 40mg strength (equivalent to 4000 IU anti-Factor Xa activity) is primarily used for prophylaxis against deep vein thrombosis (DVT) and pulmonary embolism (PE) in medical and surgical patients, and for the treatment of acute coronary syndromes (ACS) in the Indian context.
| Onset | Duration | Bioavailability |
|---|---|---|
| 3-5 hours after subcutaneous injection for peak anti-Factor Xa activity. | Approximately 12 hours for a single subcutaneous dose. | Approximately 92% after subcutaneous administration. |
2. Mechanism of Action
Enoxaparin binds to and potentiates the activity of antithrombin III (AT-III), a natural inhibitor of coagulation enzymes. This binding causes a conformational change in AT-III, dramatically accelerating its rate of inhibition of activated coagulation Factor X (Xa). It has a higher ratio of anti-Factor Xa to anti-Factor IIa (thrombin) activity (approximately 3.8:1) compared to unfractionated heparin.
3. Indications & Uses
- Prophylaxis of deep vein thrombosis (DVT) and pulmonary embolism (PE) in patients undergoing abdominal surgery, hip or knee replacement surgery, or medical patients at risk due to severely restricted mobility during acute illness.
- Treatment of acute ST-segment elevation myocardial infarction (STEMI) in patients <75 years receiving thrombolytic therapy (as per Indian guidelines).
- Prophylaxis of ischemic complications in patients with unstable angina and non-Q-wave myocardial infarction (NSTEMI/UA).
4. Dosage & Administration
Adult Dosage: **DVT/PE Prophylaxis (Surgical/Medical):** 40 mg (4000 IU) SC once daily, starting 2 hours pre-op (surgical) or at admission (medical). **ACS (Unstable Angina/NSTEMI):** 1 mg/kg SC every 12 hours (concomitant with aspirin). **STEMI (<75 years with thrombolytic):** 30 mg IV bolus followed by 1 mg/kg SC every 12 hours (max 100 mg for first two doses).
Administration: For subcutaneous use only. Administer by deep SC injection into the abdominal wall, alternating sides. Use prefilled syringe. Do not expel air bubble. Pinch a skin fold between thumb and forefinger and insert needle at a 90-degree angle. Do not rub the injection site. Do not mix with other injections. Intramuscular injection is contraindicated.
5. Side Effects
Common side effects may include:
- Injection site reactions: pain, hematoma, erythema, ecchymosis.
- Mild elevation of liver transaminases (AST/ALT).
- Minor bleeding (e.g., epistaxis, gum bleeding).
6. Drug Interactions
| Drug | Effect | Severity |
|---|---|---|
| Oral Anticoagulants (Warfarin, Acenocoumarol) | Increased risk of bleeding. Monitor INR closely during overlap. | Major |
| Antiplatelet Agents (Aspirin, Clopidogrel, Ticagrelor) | Additive risk of bleeding, but often used together in ACS. Monitor for signs of bleeding. | Major |
| NSAIDs (Diclofenac, Ibuprofen, Naproxen) | Increased bleeding risk due to antiplatelet effect and GI irritation. | Moderate |
| Thrombolytics (Streptokinase, Alteplase) | Profound increase in bleeding risk. Used together in STEMI with specific protocols. | Major |
| Other Anticoagulants (Fondaparinux, Dabigatran) | Concomitant use is generally contraindicated due to excessive bleeding risk. | Major |
| Herbal Supplements (Ginkgo biloba, Garlic, Ginseng) | Potential increased bleeding risk. | Moderate |
7. Patient Counselling
- **DO** inject at the same time each day as prescribed.
- **DO** rotate injection sites on the abdomen.
- **DO** inform all healthcare providers (dentist, surgeon) that you are on enoxaparin.
- **DO** use a soft-bristle toothbrush and electric razor to minimize minor bleeding.
- **DON'T** rub the injection site after administration.
- **DON'T** take aspirin, NSAIDs (like ibuprofen), or other blood thinners without consulting your doctor.
- **DON'T** inject intramuscularly or into a vein.
- **DON'T** change the dose or stop taking it without medical advice.
8. Toxicology & Storage
Overdose: Manifested as bleeding complications ranging from minor oozing at injection sites to major internal hemorrhage (e.g., GI, intracranial).
Storage: Store at room temperature (15°C to 25°C). Do not freeze. Keep in original package to protect from light. Keep out of reach of children. Do not use if the solution is discolored or contains particles. Prefilled syringes are for single use only; discard any unused portion.