Enoxaparin

# Enoxaparin ## Overview - **Classification**: Low Molecular Weight Heparin (LMWH) - **Mechanism**: Potentiates antithrombin III, leading to accelerated inactivation of Factor Xa (primarily) and, to a lesser extent, Factor IIa (thrombin). ## Primary Indications 1. **VTE Prophylaxis** - Prevention of venous thromboembolism (DVT/PE) in surgical/medical patients. 2. **VTE Treatment** - Treatment of acute deep vein thrombosis (DVT) and pulmonary embolism (PE). 3. **STEMI** - Treatment of acute ST-segment elevation myocardial infarction (STEMI) managed medically or with PCI. ## Adult Dosing ### Standard Dosing **VTE Prophylaxis (Medical/Surgical)** - **Dose**: **40 mg** - **Frequency**: Once daily (QD) - **Route**: Subcutaneous (SC) - **Special considerations**: **30 mg** SC every 12 hours for hip replacement (initial), knee replacement, abdominal surgery. **VTE Treatment (DVT/PE)** - **Dose**: **1 mg/kg** - **Frequency**: Every 12 hours (Q12H) - **Route**: Subcutaneous (SC) - **Alternative**: **1.5 mg/kg** SC once daily (QD) for inpatient DVT/PE without PE. **STEMI** - **Dose**: **30 mg** IV bolus followed by **1 mg/kg** SC - **Frequency**: Every 12 hours (Q12H) for SC doses - **Route**: Intravenous (IV) then Subcutaneous (SC) - **Maximum dose**: Max **100 mg** for first two SC doses (then regular 1 mg/kg). ### Dose Adjustments - **Renal Impairment**: - **CrCl 15-30 mL/min**: Prophylaxis: **30 mg** SC QD. Treatment: **1 mg/kg** SC QD. - **CrCl < 15 mL/min**: Generally not recommended; consider unfractionated heparin. - **Hepatic Impairment**: No specific dose adjustment guidelines. Use with caution. - **Elderly Patients**: No dose adjustment solely based on age. Monitor renal function closely. ## Pediatric Dosing **Indication for all pediatric age groups below**: VTE Treatment or Prophylaxis. Dosing should be guided by anti-Factor Xa levels. Target anti-Xa range for treatment is typically **0.5-1.0 U/mL**. ### Neonates (0-28 days) - **Dose**: **0.75 mg/kg** - **Frequency**: Every 12 hours (Q12H) - **Maximum**: No specific max dose, but monitor anti-Xa levels to guide therapy. - **Special Notes**: Requires careful calculation from multi-dose vial. Anti-Xa levels 4 hours post-dose are crucial. ### Infants (1-12 months) - **Dose**: **1.5 mg/kg** - **Frequency**: Every 12 hours (Q12H) - **Maximum**: No specific max dose, but monitor anti-Xa levels to guide therapy. - **Special Notes**: Higher dose than neonates due to larger volume of distribution and faster clearance. ### Children (1-12 years) - **Dose**: **1 mg/kg** - **Frequency**: Every 12 hours (Q12H) - **Maximum**: Max **100 mg** per dose for initial doses. - **Special Notes**: Dose similar to adults, but still requires anti-Xa monitoring, especially in obesity or renal dysfunction. ### Adolescents (13-18 years) - **Dose**: **1 mg/kg** - **Frequency**: Every 12 hours (Q12H) or **1.5 mg/kg** QD - **Maximum**: Adult maximum doses apply (e.g., **100 mg** for first two STEMI doses). - **Special Notes**: Treat as adult dosing, but consider weight and renal function. Anti-Xa monitoring may be helpful in complex cases. ## Safety Information ### Contraindications - **Absolute**: Active major bleeding - **Absolute**: History of heparin-induced thrombocytopenia (HIT) with or without thrombosis - **Absolute**: Hypersensitivity to enoxaparin, heparin, or pork products - **Absolute**: Spinal or epidural hematoma risk (e.g., recent or anticipated neuraxial anesthesia/lumbar puncture) ### Common Adverse Effects - **Very Common (>10%)**: Hemorrhage, anemia - **Common (1-10%)**: Thrombocytopenia, injection site hematoma, elevated liver enzymes - **Serious but Rare**: Heparin-Induced Thrombocytopenia (HIT), major bleeding (e.g., intracranial, retroperitoneal), anaphylaxis ### Key Drug Interactions - **Anticoagulants (e.g., warfarin, dabigatran)**: Increased risk of bleeding. Avoid concomitant use when possible. - **Antiplatelet agents (e.g., aspirin, clopidogrel, NSAIDs)**: Increased risk of bleeding. Monitor closely. - **Thrombolytics**: Greatly increased risk of bleeding. Use with extreme caution. ## Monitoring & Follow-up - **Before Treatment**: Baseline CBC (platelets), PT/INR, aPTT, renal function (CrCl). - **During Treatment**: - CBC with platelets: Regularly, especially for HIT risk (e.g., every 2-3 days during first 2 weeks). - Anti-Factor Xa levels: For select populations (e.g., pediatrics, renal impairment, obesity, pregnancy). - Signs/symptoms of bleeding. - **Clinical Signs**: Watch for unusual bruising, petechiae, melena, hematuria, prolonged bleeding from minor cuts. ## Clinical Pearls - 💡 **Administration**: Administer SC deep into the fat layer, alternating sites (abdomen preferred). Do not expel the air bubble. - 💡 **Reversal**: Protamine sulfate is the antidote, partially reversing anti-Xa activity. - 💡 **Weight-Based Dosing**: For treatment, base doses on actual body weight unless extreme obesity. - 💡 **Bridging**: Enoxaparin is often used as a bridge to oral anticoagulants like warfarin. > **⚠️ Important**: This information is for educational purposes only. Always consult current prescribing information, local guidelines, and clinical judgment before prescribing.