HEPARIN SODIUM 2,000 UNITS IN SODIUM CHLORIDE 0.9% IN PLASTIC CONTAINER
Clinical safety rating
safeNo significant drug interactions Can cause hypernatremia and fluid overload.
Heparin binds to antithrombin III, causing a conformational change that accelerates the inactivation of thrombin (factor IIa) and activated factor X (factor Xa), thereby inhibiting coagulation.
| Metabolism | Heparin is primarily metabolized by the reticuloendothelial system (liver and spleen) via desulfation and depolymerization, with partial metabolism by the kidney. It is excreted in urine as unchanged drug and metabolites. |
| Excretion | Heparin is primarily cleared by the reticuloendothelial system and the liver, where it undergoes desulfation and depolymerization. Renal excretion of intact heparin accounts for <10% of total clearance. Biliary/fecal elimination is negligible. |
| Half-life | The terminal elimination half-life of heparin is dose-dependent: at 100 U/kg IV, approximately 60 minutes; at 400 U/kg, approximately 150 minutes. The half-life is prolonged in hepatic dysfunction and shortened in pulmonary embolism. |
| Protein binding | Heparin binds to antithrombin III (ATIII), heparin cofactor II, and other plasma proteins. Protein binding is high but variable (often reported as >90%) due to binding to ATIII and nonspecific binding. |
| Volume of Distribution | The apparent volume of distribution (Vd) is approximately 0.06 L/kg (range 0.04-0.07 L/kg). This low Vd reflects confinement to the vascular space. |
| Bioavailability | Subcutaneous: approximately 20-30% due to binding to endothelial cells and macrophages. IV: 100%. |
| Onset of Action | IV: Immediate (within minutes). Subcutaneous: Approximately 1-2 hours (therapeutic effect may take 2-4 hours). |
| Duration of Action | IV: 2-6 hours depending on dose. Subcutaneous: 8-12 hours (with higher doses may last up to 24 hours). Monitoring aPTT is required for dose adjustment. |
| Molecular Weight | 15000 Da (unfractionated heparin, average) |
Intravenous: Initial bolus of 5,000-10,000 units, followed by continuous infusion at 15-25 units/kg/hour. Subcutaneous: 5,000-10,000 units every 8-12 hours. Dose adjusted to maintain aPTT 1.5-2.5 times control.
| Dosage form | INJECTABLE |
| Renal impairment | No specific dose adjustment required for GFR ≥30 mL/min. For GFR <30 mL/min, use with caution and monitor aPTT closely; consider dose reduction of 25-50%. |
| Liver impairment | Child-Pugh Class A: No adjustment. Child-Pugh Class B: Use with caution, monitor aPTT; consider dose reduction of 25-50%. Child-Pugh Class C: Avoid use due to increased bleeding risk; if necessary, use with extreme caution and reduce dose by 50-75%. |
| Pediatric use | Intravenous: Initial bolus 75-100 units/kg, then continuous infusion 20-25 units/kg/hour. Subcutaneous: 75-100 units/kg every 8 hours. Adjust to target anti-factor Xa level of 0.3-0.7 units/mL. |
| Geriatric use | Elderly patients have reduced clearance; start with lower end of dosing range (e.g., initial bolus 5,000 units, infusion at 15-20 units/kg/hour) and monitor aPTT frequently due to increased risk of bleeding. |
| 1st trimester | Heparin does not cross the placenta; no known teratogenic effects. Use is considered safe if clinically indicated. |
| 2nd trimester | No increased risk of fetal harm; heparin is preferred for anticoagulation during pregnancy due to lack of placental transfer. |
| 3rd trimester | Use with caution due to risk of maternal hemorrhage at delivery; can be used for thromboprophylaxis but may need reversal before labor. |
Clinical note
No significant drug interactions Can cause hypernatremia and fluid overload.
| FDA category | Animal |
| Placental transfer | None; heparin does not cross the placenta due to high molecular weight and negative charge. |
| Breastfeeding | Heparin does not enter breast milk due to high molecular weight and ionized state; compatible with breastfeeding. |
| Lactation Rating | Safe (L1) |
| Teratogenic Risk | Heparin does not cross the placenta and is not associated with teratogenic risk. No increased risk of fetal malformations has been reported. First trimester: no known risk. Second trimester: no known risk. Third trimester: no known risk. |
| Fetal Monitoring | Monitor platelet counts regularly for heparin-induced thrombocytopenia (HIT). Monitor activated partial thromboplastin time (aPTT) for anticoagulant effect. Assess for signs of bleeding or hemorrhage. Fetal monitoring: nonstress test or biophysical profile if indicated for maternal condition. |
| Fertility Effects | No known adverse effects on fertility. Heparin does not affect reproductive function or gamete integrity. |
■ FDA Black Box Warning
Heparin should not be used interchangeably with heparin lock flush or other heparin products. Fatal hemorrhage can occur. Monitor for thrombocytopenia and signs of bleeding. Heparin-induced thrombocytopenia (HIT) can lead to new thrombotic events.
| Common Effects | fluid replacement |
| Serious Effects |
Active major bleedingHemophilia or other coagulation disordersSevere thrombocytopenia (e.g., heparin-induced thrombocytopenia)Hypersensitivity to heparin or pork productsIntracranial hemorrhageInability to perform regular coagulation monitoring
| Precautions | Monitor for signs of bleeding, especially in patients with renal impairment, hypertension, or gastrointestinal lesions., Heparin-induced thrombocytopenia (HIT) with thrombosis (HITT) can occur; discontinue if platelets fall significantly., Use with caution in patients with bleeding disorders, recent surgery, or hypersensitivity to heparin., Protamine sulfate should be available for reversal of overdose. |
| Food/Dietary | No known food interactions. Maintain a consistent intake of vitamin K-rich foods if also on warfarin; otherwise, no dietary restrictions. |
| Clinical Pearls | Monitor aPTT 6 hours after initiation and after dose changes; target 1.5-2.5 times control. Use weight-based dosing for therapeutic anticoagulation (e.g., 80 units/kg bolus then 18 units/kg/hour). Avoid IM injections due to hematoma risk. Reversal agent: protamine sulfate (1 mg per 100 units heparin). Check platelet count regularly for heparin-induced thrombocytopenia (HIT). Use with caution in renal impairment. |
| Patient Advice | Report any unusual bleeding, bruising, or dark stools immediately. · Avoid aspirin, NSAIDs, and other blood thinners unless prescribed. · Use a soft toothbrush and electric razor to prevent cuts. · Inform all healthcare providers that you are on heparin. · Do not stop or change the dose without consulting your doctor. |
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