HEPARIN SODIUM 12,500 UNITS IN DEXTROSE 5% IN PLASTIC CONTAINER
Clinical safety rating: safe
Other drugs that affect hemostasis increase bleeding risk Can cause heparin-induced thrombocytopenia (HIT) and bleeding.
Heparin binds to antithrombin III (ATIII) and accelerates its inhibition of thrombin (factor IIa) and other serine proteases (factors Xa, IXa, XIa, XIIa) in the coagulation cascade, thereby preventing fibrin clot formation.
| Metabolism | Primarily cleared by the reticuloendothelial system and metabolized in the liver via desulfation and depolymerization; partially renally excreted as unchanged drug. Metabolism is saturable and dose-dependent. |
| Excretion | Heparin is eliminated primarily via hepatic metabolism and renal excretion. Approximately 50% of a dose undergoes hepatic desulfation and depolymerization to form uroheparin, which is excreted in urine. Unchanged heparin is cleared renally via saturable, dose-dependent mechanisms. Biliary/fecal elimination is negligible (<5%). |
| Half-life | Terminal elimination half-life is 1-2 hours at therapeutic doses, dose-dependent: 30-60 min after IV bolus of 25 U/kg, increasing to 1.5-2.5 hours after 400 U/kg. Prolonged in hepatic/renal impairment and pulmonary embolism. Clinical context: continuous infusion achieves steady-state after ~4-6 hours. |
| Protein binding | High protein binding to antithrombin III (ATIII), albumin, and other proteins; overall ~95% bound. |
| Volume of Distribution | 0.05-0.07 L/kg (confined to plasma volume). Distribution is limited due to high protein binding and large molecular weight; does not cross placenta or blood-brain barrier. |
| Bioavailability | SC: ~30% (variable due to binding to endothelial cells and macrophages). IV: 100%. IM: not recommended. Oral: negligible (<1% due to GI degradation and large molecular size). |
| Onset of Action | Intravenous (IV): immediate (anticoagulation within 1-2 minutes). Subcutaneous (SC): delayed (20-30 minutes to peak effect). Not administered IM due to hematoma risk. |
| Duration of Action | IV bolus: 2-4 hours (dose-dependent). Continuous IV infusion: sustained effect. SC: 8-12 hours. Effects reversed within 2-4 hours after discontinuation. Protamine sulfate reverses within 5 minutes. |
Continuous IV infusion: Initial bolus 80 units/kg, then 18 units/kg/hour; subsequent dose adjusted based on aPTT. Typical infusion rate: 20,000–40,000 units/24 hours.
| Dosage form | INJECTABLE |
| Renal impairment | No specific GFR-based dose adjustment required; monitor aPTT closely in renal impairment due to accumulation risk. |
| Liver impairment | Child-Pugh A: No adjustment. Child-Pugh B or C: Reduce dose by 25–50% and monitor aPTT frequently due to decreased anticoagulant factors. |
| Pediatric use | IV bolus: 75–100 units/kg; maintenance: 20 units/kg/hour continuous infusion; adjust to target aPTT (e.g., 60–85 seconds). Monitor closely. |
| Geriatric use | Initial bolus and infusion rates at lower end of range; consider 50 units/kg bolus and 15 units/kg/hour due to increased bleeding risk and reduced clearance. |
| 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 its high molecular weight and poor oral bioavailability; therefore, it is considered compatible with breastfeeding. M/P ratio is not applicable. |
| Teratogenic Risk | Heparin does not cross the placenta and is not associated with teratogenic effects. No increased risk of fetal malformations has been observed in any trimester. |
■ FDA Black Box Warning
Spinal/epidural hematoma risk in patients receiving neuraxial anesthesia or spinal puncture: Use of anticoagulants, including heparin, increases risk of spinal or epidural hematoma resulting in long-term or permanent paralysis. Monitor for signs/symptoms of neurological impairment and treat urgently.
| Common Effects | bleeding |
| Serious Effects |
Active major bleeding or bleeding disorders (e.g., hemophilia, thrombocytopenia), history of heparin-induced thrombocytopenia (HIT), severe uncontrolled hypertension, recent surgery of eye/brain/spinal cord, known hypersensitivity to heparin or pork products, and inability to perform adequate coagulation monitoring.
| Precautions | Hemorrhage: Major bleeding risk; monitor aPTT and adjust dose. Heparin-induced thrombocytopenia (HIT): Monitor platelet counts; discontinue if HIT suspected. Osteoporosis: Long-term use associated with bone loss. Hyperkalemia: Due to aldosterone suppression. Preservative-free formulation required for neonates/infants to avoid benzyl alcohol toxicity. |
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| Fetal Monitoring | Monitor maternal platelet counts for heparin-induced thrombocytopenia (HIT), signs of bleeding, and activated partial thromboplastin time (aPTT) to maintain therapeutic levels. Fetal monitoring is not required as heparin does not cross the placenta. |
| Fertility Effects | Heparin is not known to affect fertility in males or females. No reproductive toxicity has been reported. |