HEPARIN SODIUM 25,000 UNITS IN DEXTROSE 5%
Clinical safety rating: safe
Other drugs that affect hemostasis increase bleeding risk Can cause heparin-induced thrombocytopenia (HIT) and bleeding.
Heparin sodium binds to antithrombin III (ATIII), inducing a conformational change that accelerates ATIII-mediated inactivation of factor Xa and thrombin (factor IIa), thereby inhibiting coagulation.
| Metabolism | Heparin is partially metabolized in the liver by depolymerization and desulfation via heparinase; also cleared by the reticuloendothelial system. Unchanged drug and metabolites are excreted in urine. |
| Excretion | Renal: negligible; primarily metabolized by the liver and reticuloendothelial system; small amount excreted unchanged in urine (<5%). Biliary/fecal: minimal. |
| Half-life | Terminal elimination half-life is approximately 1.5 hours (range 1–2 hours) after intravenous administration; dose-dependent: at therapeutic doses, half-life is about 1 hour; at higher doses, up to 2.5 hours. Clinical context: shorter half-life in pulmonary embolism, longer in renal impairment. |
| Protein binding | Very high: 95–98% bound; primarily to antithrombin III (ATIII) with some binding to albumin and other plasma proteins. |
| Volume of Distribution | 0.06–0.1 L/kg (limited to plasma volume; does not distribute into extravascular spaces). Clinical meaning: small Vd indicates heparin remains largely in the vascular compartment with minimal tissue penetration. |
| Bioavailability | Intravenous: 100%. Subcutaneous: approximately 30–40% (due to poor absorption of large molecule; higher doses may achieve up to 50% bioavailability). |
| Onset of Action | Intravenous: immediate (within minutes). Subcutaneous: 20–60 minutes (with 20,000–40,000 U/mL concentration, onset delayed to 1–2 hours). |
| Duration of Action | Intravenous: 2–6 hours (dose-dependent; effects wear off within 2–4 hours after bolus). Subcutaneous: 8–12 hours (with continuous infusion, duration is sustained). Clinical note: effects can be prolonged in renal failure or with higher doses. |
Initial IV bolus of 5000 units, followed by continuous IV infusion at 1300 units/hour (typically 25,000 units in 500 mL D5W at 26 mL/hour) for therapeutic anticoagulation; dose titrated to aPTT 1.5-2.5 times control.
| Dosage form | INJECTABLE |
| Renal impairment | No specific dose adjustment required for GFR; however, heparin is eliminated renally, and accumulation may occur in severe renal impairment (CrCl <30 mL/min). Monitor aPTT closely and reduce infusion rate if prolonged. |
| Liver impairment | No specific dose adjustment based on Child-Pugh score; however, hepatic impairment may reduce anticoagulant effect due to decreased synthesis of coagulation factors. Monitor aPTT and adjust dose accordingly. |
| Pediatric use | Neonates and infants: initial IV bolus 75 units/kg, then continuous infusion 28 units/kg/hour (for age <1 year). Children >1 year: initial IV bolus 75 units/kg, then infusion 20 units/kg/hour. Titrate to aPTT 60-85 seconds. |
| Geriatric use | Elderly patients may have increased sensitivity to heparin due to reduced renal function and decreased clearance. Consider lower initial infusion rate (e.g., 1000 units/hour) and monitor aPTT more frequently to avoid bleeding. |
| 1st trimester | Consult provider |
| 2nd trimester | Consult provider |
| 3rd trimester | Consult provider |
Clinical note
Other drugs that affect hemostasis increase bleeding risk Can cause heparin-induced thrombocytopenia (HIT) and bleeding.
| FDA category | Human |
| Breastfeeding | Heparin is not excreted into breast milk due to high molecular weight and protein binding. M/P ratio is negligible. Considered safe during breastfeeding, though caution with high doses due to theoretical risk of infant anticoagulation. |
| Teratogenic Risk | Heparin does not cross the placenta and is not teratogenic. No increased risk of fetal malformations reported in any trimester. Considered low risk for embryotoxicity. |
■ FDA Black Box Warning
Heparin is not intended for intramuscular injection due to risk of hematoma. Spinal or epidural hematomas can occur in patients anticoagulated with heparin who receive neuraxial anesthesia or spinal puncture, resulting in long-term or permanent paralysis. Risk is increased by use of indwelling epidural catheters, concomitant use of drugs affecting hemostasis, or a history of traumatic or repeated epidural/spinal punctures. Monitor patients for signs and symptoms of neurological impairment.
| Common Effects | bleeding |
| Serious Effects |
["Hypersensitivity to heparin or any component","History of heparin-induced thrombocytopenia (HIT) or heparin-induced thrombocytopenia and thrombosis (HITT)","Active major bleeding or hemorrhagic disorders (e.g., hemophilia, thrombocytopenic purpura)","Severe thrombocytopenia (platelet count < 100,000/mm³)","Uncontrollable bleeding (except when due to disseminated intravascular coagulation)","Suspected intracranial hemorrhage or spinal cord injury","Inability to perform appropriate coagulation monitoring (e.g., aPTT)"]
| Precautions |
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| Fetal Monitoring | Monitor maternal aPTT, platelet counts (risk of heparin-induced thrombocytopenia), signs of bleeding, osteoporosis with prolonged use. Fetal monitoring: ultrasound for growth and well-being if indicated by underlying condition. |
| Fertility Effects | No known adverse effects on fertility or reproduction. Heparin is not associated with hormonal alterations affecting conception. |
| ["Hemorrhage: Major hemorrhage may occur; monitor coagulation tests and adjust dose. Use caution in conditions with increased bleeding risk.","Thrombocytopenia: Heparin-induced thrombocytopenia (HIT) may occur; monitor platelet counts. Discontinue heparin if HIT is suspected.","Heparin resistance: May occur in patients with antithrombin III deficiency or elevated factor VIII.","Hyperkalemia: May suppress adrenal aldosterone secretion, leading to hyperkalemia; monitor potassium levels.","Osteoporosis: Long-term use may increase risk of osteoporosis and fractures.","Heparin use in pregnancy: Contains benzyl alcohol (preservative), which can cause gasping syndrome in neonates; use preservative-free formulation if possible."] |