HEPARIN SODIUM 2,000 UNITS IN SODIUM CHLORIDE 0.9% IN PLASTIC CONTAINER
Clinical safety rating: safe
No 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. |
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 | Consult provider |
| 2nd trimester | Consult provider |
| 3rd trimester | Consult provider |
Clinical note
No significant drug interactions Can cause hypernatremia and fluid overload.
| FDA category | Animal |
| Breastfeeding | Heparin is not excreted into breast milk due to its high molecular weight and polarity. M/P ratio is not applicable. Considered compatible with breastfeeding. |
| 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. |
■ 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 |
["Uncontrolled active bleeding","History of heparin-induced thrombocytopenia (HIT) or hypersensitivity to heparin","Severe thrombocytopenia","When suitable blood coagulation tests cannot be performed at appropriate intervals"]
| 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."] |
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| 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. |