Heparin
HEPARIN SODIUM
What it isAntithrombin activator inhibiting thrombin and factor Xa; anticoagulation.
Why this oneIts short half-life and complete protamine reversal make it the anticoagulant when bleeding risk is high or surgery is near.
What limits itRequires aPTT or anti-Xa monitoring. Heparin-induced thrombocytopenia demands platelet monitoring and immediate cessation.
FDA-approved for
- thrombosis prophylaxis and treatment
FDA label
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| FDA dosing | Population | Start | Target | Max |
|---|---|---|---|---|
| Therapeutic anticoagulation — deep SC | Adults | 5,000 units IV, then 10,000-20,000 units SC | 8,000-10,000 units q8h or 15,000-20,000 units q12h SC | |
| Therapeutic anticoagulation — intermittent IV | Adults | 10,000 units IV | 5,000-10,000 units q4-6h IV | |
| Therapeutic anticoagulation — IV infusion | Adults | 5,000 units IV bolus | 20,000-40,000 units/24 h continuous infusion | |
| Low-dose prophylaxis of postoperative thromboembolism | Adults | 5,000 units SC 2 h pre-op | 5,000 units q8-12h SC x7 days or until ambulatory | |
| Cardiovascular (open-heart) surgery | Adults | ≥150 units/kg IV initial | 300 units/kg (<60 min) or 400 units/kg (>60 min) | |
| Extracorporeal dialysis | Adults | 25-30 units/kg | 1,500-2,000 units/hr infusion |
Renal Undefined
Hepatic Undefined
Adjust dose to aPTT 1.5-2× normal (or clotting time 2.5-3× control); monitor platelet counts
Instructions
- Confirm correct vial strength before use (fatal medication errors with mix-ups)
- Give by IV injection, IV infusion, or deep SC (intrafat); do NOT give IM (hematoma risk)
- Use preservative-free heparin in neonates/infants and, if available, in pregnancy/lactation
- When converting to warfarin, continue full heparin until INR therapeutic, then stop without tapering
Contraindications
- History of heparin-induced thrombocytopenia (HIT) / HIT with thrombosis (HITT)
- Known hypersensitivity to heparin or pork products (anaphylactoid reactions)
- Uncontrolled active bleeding (except when due to DIC)
- Severe thrombocytopenia
- Inability to perform coagulation monitoring at appropriate intervals (full-dose heparin)
Cautions
- Hemorrhage — can be fatal; use caution in conditions with increased bleeding risk
- HIT and HITT — monitor platelets; discontinue if count <100,000 or new thrombosis
- Fatal medication errors from vial strength confusion
- Benzyl alcohol toxicity (gasping syndrome) in neonates/infants
- Hyperkalemia (aldosterone suppression)
- Heparin resistance in fever, thrombosis, infection, malignancy
Adverse reactions
- Hemorrhage
- Thrombocytopenia; HIT/HITT
- Injection-site irritation, hematoma, skin necrosis
- Hypersensitivity reactions (chills, fever, urticaria, anaphylactoid)
- Elevated AST/ALT
- Osteoporosis with long-term high-dose use
Pregnancy No evidence of increased fetal risk in humans; use preservative-free formulation when possible
Lactation Not likely excreted in milk (large molecule) and not orally absorbed; use preservative-free formulation
NO BOXED WARNINGS
Principal riskHIT requires platelet monitoring; short half-life, protamine-reversible
Cost, est. cash$10–$500/bag or supply
Generic entryBy 2023
Classes and tags
Clinical profile
Legacy pregnancy categoryUnknown / historical label unavailable
Defining liabilityUsually well tolerated at replacement doses; excessive dosing can cause agent-specific metabolic or organ toxicity.
Mechanism of action: Heparin ballicule
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Memory aids: mascots and interaction avatars
bananas in bunches → increases serum potassium
