HEPARIN SODIUM 1,000 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, inducing a conformational change that accelerates the inhibition of thrombin (factor IIa) and activated factor X (Xa). This prevents the conversion of fibrinogen to fibrin and inhibits clot formation.
| Metabolism | Heparin is metabolized in the liver and by the reticuloendothelial system; undergoes desulfation and depolymerization. Metabolites are excreted renally. |
| Excretion | Renal (minimal, saturable) and reticuloendothelial system (heparinase). Unchanged heparin: negligible urinary excretion. Metabolites: desulfated heparin via hepatic and extrahepatic heparinase; inactive fragments cleared renally. |
| Half-life | Dose-dependent: 30–60 min after 25 U/kg IV, 60–90 min after 100 U/kg IV, 150 min after 400 U/kg IV. Terminal half-life: ~1.5 h (low dose) to ~5 h (high dose). Context: nonlinear due to saturable clearance mechanisms. |
| Protein binding | Very high: >90% bound to antithrombin III (AT-III), with additional low-affinity binding to albumin, globulins, fibrinogen, and lipoproteins. Effective free fraction ~5%. |
| Volume of Distribution | 0.05–0.07 L/kg (low, primarily confined to plasma). Clinical meaning: reflects limited extravascular distribution; heparin remains largely in plasma and interstitial fluid. |
| Bioavailability | Subcutaneous: ~30–50% (dose-dependent, higher with lower doses due to saturable binding). IV: 100%. Not absorbed orally. |
| Onset of Action | IV: immediate (seconds). Subcutaneous: 20–30 min for therapeutic APTT prolongation. |
| Duration of Action | IV bolus: 2–4 h (effects on APTT). Continuous IV infusion: sustained. Subcutaneous: 6–8 h (dose-dependent). Clinical: effect monitored by APTT; rebound hypercoagulability possible after abrupt cessation. |
| Molecular Weight | 15000 |
Continuous intravenous infusion: initial bolus 80 units/kg (max 10,000 units) followed by infusion at 18 units/kg/hour (usual adult dose 1,000-2,000 units/hour). For prophylactic use: subcutaneous 5,000 units every 8-12 hours.
| Dosage form | INJECTABLE |
| Renal impairment | No specific GFR-based dose adjustment; however, reduced clearance may require monitoring of aPTT and dose titration. For severe renal impairment (CrCl <30 mL/min), consider dose reduction or alternative agent. |
| Liver impairment | Child-Pugh Class A: no adjustment. Class B: reduce initial dose by 25-50% and monitor aPTT. Class C: avoid use due to increased bleeding risk. |
| Pediatric use | Continuous IV infusion: initial bolus 75-100 units/kg over 10 minutes, then maintenance infusion: infants <1 year: 28 units/kg/hour; children >1 year: 20 units/kg/hour. Titrate to aPTT 60-85 seconds. |
| Geriatric use | Elderly patients have altered pharmacokinetics: lower initial bolus (50-60 units/kg) and infusion rate (15 units/kg/hour) recommended due to increased bleeding risk; monitor aPTT closely. |
| 1st trimester | Heparin does not cross the placenta and is not associated with teratogenicity. Use is considered safe when indicated. |
| 2nd trimester | Safe for use when indicated; no significant risk. |
| 3rd trimester | Safe for use; however, monitor for maternal bleeding risk, especially near term. |
Clinical note
Other drugs that affect hemostasis increase bleeding risk Can cause heparin-induced thrombocytopenia (HIT) and bleeding.
| FDA category | Human |
| Placental transfer | Heparin does not cross the placenta due to its high molecular weight and negative charge. |
| Breastfeeding | Heparin is not excreted into breast milk due to its high molecular weight and poor oral bioavailability, making it safe during breastfeeding. |
■ FDA Black Box Warning
Heparin is not recommended for intramuscular use due to risk of hematoma.
| Common Effects | bleeding |
| Serious Effects |
Active major bleedingSevere thrombocytopenia (e.g., heparin-induced thrombocytopenia)Known hypersensitivity to heparinUncontrollable bleeding states
| Precautions | Risk of hemorrhage; monitor coagulation parameters (aPTT, anti-Xa), platelet counts (risk of heparin-induced thrombocytopenia, HIT), Heparin-induced thrombocytopenia (HIT) can lead to thrombosis (HITT); may require alternative anticoagulation, Protamine sulfate is an antidote for overdose; use with caution in patients with renal impairment, Avoid in patients with severe hypertension, recent surgery of eye/brain/spine, or active bleeding, May cause hyperkalemia by suppressing aldosterone, especially in diabetic or renally impaired patients |
| Food/Dietary |
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| Lactation Rating | L1 |
| Teratogenic Risk | Heparin does not cross the placenta and is not associated with teratogenicity. No increased risk of fetal malformations in any trimester. |
| Fetal Monitoring | Monitor platelet count for heparin-induced thrombocytopenia, signs of bleeding, and activated partial thromboplastin time (aPTT) during therapy. For long-term use, monitor bone density and antithrombin levels. |
| Fertility Effects | No known adverse effects on fertility. Heparin does not affect reproductive hormones or gamete function. |
| No known food interactions. Avoid excessive alcohol consumption as it may increase bleeding risk. Maintain adequate hydration. |
| Clinical Pearls | Heparin 1000 units in D5W is typically used as a flush solution to maintain patency of IV catheters; not for therapeutic anticoagulation. Monitor for heparin-induced thrombocytopenia (HIT) with platelet counts. In patients with renal impairment, heparin clearance is unaffected but caution in hepatic disease. Use preservative-free heparin in neonates. Flush with normal saline first if drug incompatibility suspected. |
| Patient Advice | This medication is used to keep your IV line clean and working properly. · Tell your healthcare provider if you have had a reaction to heparin or if you have a history of low platelets. · Report any unusual bleeding, bruising, or signs of allergic reaction (rash, itching, swelling, trouble breathing). · Avoid taking aspirin, ibuprofen, or blood thinners unless prescribed by your doctor. · Inform all healthcare providers that you have an IV line with heparin. |