HEPARIN SODIUM 5,000 UNITS IN SODIUM CHLORIDE 0.45%
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 inhibition of thrombin and activated factor X (factor Xa). It also catalyzes the inhibition of other coagulation factors including XIIa, XIa, IXa, and VIIa.
| Metabolism | Heparin is partially metabolized by the reticuloendothelial system and desulfated. Clearance is dose-dependent and saturable, primarily via the liver (heparinase) and to a lesser extent renal excretion. |
| Excretion | Primarily renal, with some hepatic metabolism and reticuloendothelial system clearance. Unchanged heparin is excreted in urine via glomerular filtration; high molecular weight fractions are cleared more rapidly than low molecular weight fractions. |
| Half-life | Mean terminal elimination half-life is 1-2 hours at therapeutic doses, but it is dose-dependent and can increase with higher doses. Clinical context: Anticoagulant effect persists longer than plasma levels due to irreversible binding to antithrombin III. |
| Protein binding | Very high; ~95% bound primarily to antithrombin III, with some binding to albumin and other proteins. |
| Volume of Distribution | 0.05-0.07 L/kg (approximately 4-5 L in adults). Clinical meaning: Low Vd indicates predominantly intravascular distribution; heparin does not cross the placenta or blood-brain barrier. |
| Bioavailability | Subcutaneous: 20-30% (due to first-pass metabolism and binding); Intravenous: 100%. |
| Onset of Action | Intravenous: Immediate. Subcutaneous: 20-30 minutes. |
| Duration of Action | Intravenous: 2-6 hours (dose-dependent). Subcutaneous: 8-12 hours (prolonged with higher doses). Clinical note: Effect monitored via aPTT; prolonged use may require dose adjustment. |
| Molecular Weight | 12000 |
IV: Initial bolus 80 units/kg, then continuous infusion at 18 units/kg/hr, adjusted to aPTT 1.5-2.5 times control. Subcutaneous: 5,000 units every 8-12 hours.
| Dosage form | INJECTABLE |
| Renal impairment | CrCl <30 mL/min: Reduce infusion rate by 50% or consider alternative. Monitor aPTT closely. |
| Liver impairment | Child-Pugh Class B or C: Reduce dose by 50% due to decreased clearance; monitor aPTT. |
| Pediatric use | IV bolus 75-100 units/kg, then infusion: Infants <1 year: 28 units/kg/hr; Children >1 year: 20 units/kg/hr; adjust to aPTT 60-85 seconds. |
| Geriatric use | Reduce initial bolus to 50-60 units/kg and infusion rate to 15 units/kg/hr due to altered clearance; frequent aPTT monitoring. |
| 1st trimester | Heparin does not cross the placenta due to high molecular weight and is not associated with teratogenic risk. Use is considered safe when clinically indicated. |
| 2nd trimester | No increased risk of fetal harm; continued use is acceptable for maternal thromboembolic disorders. |
| 3rd trimester | Risk of maternal hemorrhage and osteoporosis with prolonged use; monitoring recommended. No fetal anticoagulation. |
Clinical note
No significant drug interactions Can cause hypernatremia and fluid overload.
| FDA category | Animal |
| Placental transfer | Does not cross the placenta due to molecular weight >20,000 Da and negative charge. |
| Breastfeeding | Heparin is not excreted into breast milk due to its high molecular weight and ionization, making it incompatible with milk transfer. Use is considered compatible with breastfeeding. |
| Lactation Rating | L1 (Safest) |
| Teratogenic Risk | Heparin does not cross the placenta; no known teratogenic effects in any trimester. Risk of maternal hemorrhage and fetal bleeding during delivery. |
| Fetal Monitoring | Monitor maternal aPTT, platelet count, and signs of bleeding. Fetal surveillance not required; monitor for signs of placental abruption or hemorrhage. |
| Fertility Effects | No known adverse effects on human fertility based on available data. |
■ FDA Black Box Warning
Heparin is contraindicated in patients with a history of heparin-induced thrombocytopenia (HIT). Fatal hemorrhages have occurred. Monitor platelets closely.
| Common Effects | fluid replacement |
| Serious Effects |
Severe thrombocytopenia (heparin-induced thrombocytopenia, HIT)Uncontrolled active bleeding (except when due to disseminated intravascular coagulation)Known hypersensitivity to heparin or pork productsInability to perform appropriate monitoring (e.g., aPTT)
| Precautions | Risk of hemorrhage: Monitor for bleeding, especially in patients with predisposing factors (e.g., renal failure, recent surgery)., Heparin-induced thrombocytopenia (HIT): Monitor platelet counts regularly; discontinue if HIT is suspected., Heparin-induced thrombocytopenia with thrombosis (HITT): May require alternative anticoagulation., Osteoporosis: Long-term use may lead to bone density loss., Hyperkalemia: Heparin may suppress adrenal aldosterone secretion, leading to hyperkalemia, especially in renal impairment or diabetes., Heparin resistance: May occur in antithrombin III deficiency or elevated heparin clearance. |
| Food/Dietary | No clinically significant food interactions with heparin flushes. No dietary restrictions required for this indication. |
| Clinical Pearls | HEPARIN SODIUM 5,000 UNITS IN SODIUM CHLORIDE 0.45% is a fixed-dose formulation used for venous access device flushing to maintain patency. Not for systemic anticoagulation. Verify catheter size and type to ensure appropriate flush volume. Avoid in patients with heparin-induced thrombocytopenia (HIT). Use preservative-free formulation in neonates. Monitor for signs of bleeding or hypersensitivity. Do not expel air from syringe to avoid air embolism; instead use proper priming technique. |
| Patient Advice | This medication is used to keep your IV or catheter line clear and prevent blood clots inside it. · It is a very small dose of heparin; it does not thin your blood throughout your body. · Report any unusual bleeding, bruising, or pain at the IV site to your healthcare provider. · Tell your doctor if you have ever had a reaction to heparin or a history of low platelet counts with heparin use. · Do not use this medication if you have active bleeding or a bleeding disorder. · Store at room temperature away from light and moisture. |
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