HEPARIN SODIUM 25,000 UNITS IN SODIUM CHLORIDE 0.45% IN PLASTIC CONTAINER
Clinical safety rating: safe
No significant drug interactions Can cause hypernatremia and fluid overload.
Heparin binds to antithrombin III, accelerating its inhibition of thrombin (factor IIa) and factor Xa, leading to anticoagulation.
| Metabolism | Primarily metabolized by the liver via desulfation and depolymerization; partially cleared by the reticuloendothelial system. |
| Excretion | Renal: 40% (as unchanged drug and metabolites); hepatic/biliary: minimal (<5%); fecal: negligible. |
| Half-life | Terminal elimination half-life: 1.5–2 hours (dose-dependent and saturable clearance); prolonged in hepatic/renal impairment and at higher doses. |
| Protein binding | Very high: ~95–98% (primarily to antithrombin III, also albumin and other proteins); binding is saturable. |
| Volume of Distribution | Vd: 0.05–0.1 L/kg; primarily confined to plasma volume (low distribution); minimal extravascular penetration. |
| Bioavailability | Subcutaneous: 30–35% (due to first-pass clearance and tissue binding); intravenous: 100%. |
| Onset of Action | Intravenous: immediate (within minutes); subcutaneous: 20–30 minutes; intramuscular: avoided due to hematoma risk. |
| Duration of Action | Intravenous: 2–6 hours (mean 4 hours); subcutaneous: 8–12 hours; clinical monitoring (aPTT) required for dose adjustment. |
Continuous IV infusion: Initial bolus 80 units/kg, then 18 units/kg/hour; adjust based on aPTT. Typical infusion rate: 1000-2000 units/hour for adults.
| Dosage form | INJECTABLE |
| Renal impairment | No specific GFR-based dose adjustment required; monitor aPTT closely in renal impairment due to increased bleeding risk. |
| Liver impairment | No established Child-Pugh based guidelines; use with caution and monitor aPTT due to reduced antithrombin III and increased bleeding risk. |
| Pediatric use | IV: Bolus 75-100 units/kg, then maintenance infusion 20-25 units/kg/hour; adjust to target aPTT. |
| Geriatric use | Lower initial doses recommended (e.g., bolus 50-60 units/kg, infusion 12-15 units/kg/hour) due to altered pharmacokinetics and increased bleeding risk; monitor aPTT closely. |
| 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 lack of oral bioavailability. Considered compatible with breastfeeding. M/P ratio is not available but expected to be negligible. |
| Teratogenic Risk | Heparin does not cross the placenta and has not been associated with teratogenicity in any trimester. No increased risk of fetal malformations. Prolonged use may be associated with maternal osteoporosis and hemorrhage, but fetal risks are minimal. |
■ FDA Black Box Warning
Heparin-induced thrombocytopenia (HIT) can occur; monitor platelets closely. Risk of bleeding, especially in patients with uncontrolled hypertension or concomitant use of antiplatelet agents.
| Common Effects | fluid replacement |
| Serious Effects |
["Hypersensitivity to heparin or pork products","Active major bleeding","Thrombocytopenia (platelet count <100,000/μL) due to HIT","Uncontrolled severe hypertension"]
| Precautions | Monitor for signs of bleeding; adjust dose based on aPTT. Discontinue if HIT is confirmed. Use with caution in renal impairment, hepatic disease, or history of gastrointestinal ulcers. |
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| Fetal Monitoring | Monitor maternal platelet count (risk of heparin-induced thrombocytopenia), signs of bleeding, anti-Xa levels if needed, and fetal growth and well-being with ultrasound if prolonged use. Assess for osteoporosis with long-term therapy. |
| Fertility Effects | No known adverse effects on fertility. Heparin is used in assisted reproductive technology protocols without evidence of impairment. |