HEPARIN SODIUM 20,000 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, causing a conformational change that accelerates the inactivation of thrombin and factor Xa, and to a lesser extent factors IXa, XIa, and XIIa, thereby inhibiting coagulation. It also inhibits platelet aggregation and prolongs clotting times.
| Metabolism | Heparin is partially metabolized in the liver by depolymerization and desulfation via hepatocytes and reticuloendothelial system. Unchanged heparin is also excreted in urine. Clearance is dose-dependent involving both saturable (binding to cells) and non-saturable (renal) mechanisms. |
| Excretion | Renal: 50-60% as unchanged drug via glomerular filtration; hepatic metabolism (desulfation) accounts for minor clearance; fecal elimination negligible (<1%). |
| Half-life | Terminal half-life 1.5 hours (range 1-3 hours) for therapeutic doses; dose-dependent, with higher doses prolonging half-life; half-life prolonged in hepatic or renal impairment. |
| Protein binding | Highly protein-bound: 95-99% to antithrombin III, albumin, and other plasma proteins. |
| Volume of Distribution | 0.07-0.08 L/kg; reflects low distribution primarily to intravascular space. |
| Bioavailability | Subcutaneous: 30-40% (bioavailability inversely related to dose due to saturable absorption); Intravenous: 100%. |
| Onset of Action | Intravenous: immediate (within seconds); Subcutaneous: 20-30 minutes. |
| Duration of Action | Intravenous: 2-4 hours for anticoagulant effect (aPTT elevation); Subcutaneous: 8-12 hours for prophylactic effect; duration dose-dependent. |
| Molecular Weight | 12000-15000 Da (unfractionated heparin) |
Adults: Initial IV bolus 80 units/kg, then continuous IV infusion at 18 units/kg/hour. For therapeutic anticoagulation, adjust to target aPTT 1.5-2.5 times control. Dosing per institutional nomogram.
| Dosage form | INJECTABLE |
| Renal impairment | No specific GFR-based dose adjustment required. Heparin is partially renally cleared; monitor aPTT closely in severe renal impairment (CrCl <30 mL/min) due to increased bleeding risk. |
| Liver impairment | No specific Child-Pugh based dose adjustment. Hepatic impairment may cause altered coagulation factors; monitor aPTT and adjust dose accordingly. |
| Pediatric use | Neonates and infants: Initial IV bolus 75-100 units/kg, then continuous infusion 28 units/kg/hour (neonates) or 20 units/kg/hour (infants). Older children: Initial IV bolus 75-100 units/kg, then continuous infusion 18-20 units/kg/hour. Adjust to target aPTT 1.5-2.5 times control. |
| Geriatric use | Elderly patients may have reduced heparin clearance and increased bleeding risk. Use lower initial doses (e.g., bolus 50 units/kg, infusion 15 units/kg/hour) with careful aPTT monitoring. |
| 1st trimester | Heparin does not cross the placenta and is considered safe in pregnancy; no increased risk of fetal malformations. |
| 2nd trimester | No evidence of fetal harm; continues to be safe as it does not cross placenta. |
| 3rd trimester | Safe; risk of maternal hemorrhage may increase near term; monitor anticoagulation carefully. |
Clinical note
Other drugs that affect hemostasis increase bleeding risk Can cause heparin-induced thrombocytopenia (HIT) and bleeding.
| FDA category | Human |
| Placental transfer | Does not cross placenta due to high molecular weight and negative charge. |
| Breastfeeding | Heparin is not excreted into breast milk due to high molecular weight and poor oral bioavailability; considered compatible with breastfeeding. |
■ FDA Black Box Warning
Heparin is contraindicated in patients with a history of heparin-induced thrombocytopenia (HIT) or heparin-induced thrombocytopenia and thrombosis (HITTS). Close monitoring of platelet counts is mandatory due to the risk of HIT.
| Common Effects | bleeding |
| Serious Effects |
Active major bleedingHistory of heparin-induced thrombocytopenia (HIT)Severe uncontrolled hypertensionRecent surgery of eye/brain/spinal cordHemophilia or other bleeding disordersThreatened abortionHypersensitivity to heparinInability to perform appropriate coagulation monitoring
| Precautions | Risk of major bleeding, including intracranial and retroperitoneal hemorrhage, Heparin-induced thrombocytopenia (HIT) and thrombosis (HITTS), Monitor platelet counts frequently during therapy, Use with caution in patients with increased bleeding risk (e.g., hemophilia, liver disease, recent surgery), Risk of hyperkalemia due to suppression of aldosterone, especially in patients with diabetes or renal impairment, Preservative-free formulations needed for neonates and patients with hypersensitivity to benzyl alcohol, Rebound hypercoagulability upon abrupt discontinuation, Enzyme immunoassays for HIT may yield false positives |
Loading safety data…
| Lactation Rating | L1 Safe |
| Teratogenic Risk | Heparin does not cross the placenta and is not associated with teratogenic effects. First trimester: No increased risk of major malformations. Second/third trimester: No fetal risk; however, maternal complications (e.g., hemorrhage, thrombocytopenia) may indirectly affect pregnancy. |
| Fetal Monitoring | Monitor platelet counts (risk of heparin-induced thrombocytopenia), signs of bleeding (hematuria, bruising), activated partial thromboplastin time (aPTT) to maintain therapeutic range, and fetal surveillance with nonstress test or biophysical profile if maternal condition warrants. |
| Fertility Effects | No known direct effects on fertility. Heparin does not impair spermatogenesis or oogenesis. Indirect effects may arise from underlying conditions (e.g., antiphospholipid syndrome) for which heparin is used. |
| Food/Dietary | Heparin has no direct food interactions. However, foods high in vitamin K (e.g., leafy greens) do not affect heparin's action, unlike warfarin. No specific dietary restrictions required. |
| Clinical Pearls | Use a dedicated IV line, avoid IM injection due to hematoma risk. Monitor aPTT 6 hours after bolus, adjust infusion per nomogram. For heparin-induced thrombocytopenia (HIT), check platelet count every 2-3 days. 20,000 units in D5W is a high concentration; ensure proper pump settings to avoid bolus dosing. Protamine sulfate (1 mg per 100 units heparin) reverses effect. In renal impairment, half-life may be prolonged. |
| Patient Advice | Report any signs of bleeding: unusual bruising, black/tarry stools, blood in urine, coughing up blood, or heavy menstrual bleeding. · Avoid aspirin, NSAIDs, and other blood thinners unless prescribed by your doctor. · Use soft toothbrush and electric razor to minimize bleeding risk. · Inform all healthcare providers (dentist, surgeons) that you are on heparin. · Do not stop or change the dose without consulting your doctor. · Seek immediate medical help for sudden severe headache, chest pain, difficulty breathing, or allergic reaction (rash, itching, swelling). · Remain still during infusion to prevent dislodging the IV line. |