HEPARIN SODIUM PRESERVATIVE FREE
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), causing a conformational change that accelerates the inactivation of thrombin (factor IIa) and factor Xa, as well as factors IXa, XIa, and XIIa. This inhibits clot formation and propagation.
| Metabolism | Heparin is primarily metabolized in the liver and by the reticuloendothelial system via desulfation and depolymerization; also undergoes renal clearance. |
| Excretion | Primarily renal; small amounts in urine as unchanged drug and metabolites. Biliary/fecal elimination is negligible (<5%). |
| Half-life | Terminal half-life is 0.5–2.5 hours (mean ~1.5 h) after IV administration; dose-dependent due to saturable clearance. At therapeutic doses, half-life averages 1–2 hours. |
| Protein binding | Highly bound (85–95%) to antithrombin III, albumin, and other plasma proteins. |
| Volume of Distribution | 0.03–0.06 L/kg (low, largely confined to intravascular space; does not distribute significantly into extravascular tissues). |
| Bioavailability | SC: 20–40% (due to first-pass degradation by mast cells and binding to local proteins). IV: 100%. |
| Onset of Action | IV: Immediate (within minutes). SC: 20–60 minutes (therapeutic anticoagulation in 2–4 hours with delay to steady state). |
| Duration of Action | IV: 2–6 hours (dose-dependent; higher doses prolong effect). SC: 8–12 hours (requires monitoring with aPTT at 6 h post-dose for dose adjustment). |
| Molecular Weight | 15000 |
Initial bolus of 80 units/kg IV, followed by continuous infusion at 18 units/kg/hour IV; adjusted to maintain aPTT of 1.5-2.5 times control.
| Dosage form | INJECTABLE |
| Renal impairment | No specific GFR-based dose adjustment; increased bleeding risk in severe renal impairment (CrCl <30 mL/min) with accumulation; consider dose reduction or alternative. |
| Liver impairment | No formal Child-Pugh based guidelines; use with caution due to risk of coagulopathy; monitor aPTT and adjust accordingly. |
| Pediatric use | Loading dose of 75-100 units/kg IV over 10 minutes; maintenance infusion: infants 28 units/kg/hour, children 20 units/kg/hour, adolescents 18 units/kg/hour; titrate to aPTT goal. |
| Geriatric use | Lower doses may be needed due to altered pharmacokinetics and increased bleeding risk; consider starting at lower infusion rates (e.g., 15 units/kg/hour) and titrate carefully. |
| 1st trimester | Heparin does not cross the placenta; no evidence of teratogenicity. Use if indicated. |
| 2nd trimester | Heparin does not cross the placenta; safe for use when anticoagulation is necessary. |
| 3rd trimester | Heparin does not cross the placenta; increased risk of bleeding at delivery. Monitor closely. |
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 the placenta due to high molecular weight and negative charge. |
| Breastfeeding | Heparin is not excreted into breast milk due to its high molecular weight and ionization, considered compatible with breastfeeding. |
■ FDA Black Box Warning
Heparin is not intended for intramuscular use due to risk of hematoma. Also, there is a risk of heparin-induced thrombocytopenia (HIT) and heparin-induced thrombocytopenia with thrombosis (HITT); monitor platelet counts. Preservative-free heparin should not be used in neonates or infants due to potential toxicity from benzyl alcohol (if present; however, preservative-free formulation avoids this).
| Common Effects | bleeding |
| Serious Effects |
History of heparin-induced thrombocytopenia (HIT)Active major bleeding or bleeding disorders (e.g., hemophilia, thrombocytopenia)Severe uncontrolled hypertensionRecent surgery of the eye, brain, or spinal cordHypersensitivity to heparin or pork products
| Precautions | Hemorrhage is the major complication; monitor coagulation parameters (aPTT), platelet counts, and signs of bleeding. Heparin-induced thrombocytopenia (HIT) requires immediate discontinuation. Use with caution in patients with renal impairment, hepatic disease, hypertension, or those with a history of allergies. Spinal/epidural hematoma risk with neuraxial anesthesia or spinal puncture. Not recommended for patients with severe thrombocytopenia or uncontrolled bleeding. |
Loading safety data…
| Lactation Rating | L1 - Safe |
| Teratogenic Risk | Heparin does not cross the placenta. No increased risk of fetal malformations or adverse outcomes in any trimester. Considered low risk. |
| Fetal Monitoring | Monitor activated partial thromboplastin time (aPTT) regularly. Assess for signs of bleeding, hemorrhage, and heparin-induced thrombocytopenia (HIT). Fetal monitoring includes ultrasound for growth and well-being if indicated. |
| Fertility Effects | No known adverse effects on fertility in males or females. |
| Food/Dietary | Avoid foods high in vitamin K (e.g., leafy greens, broccoli, spinach) as they may reduce anticoagulant effect. No other significant food interactions. |
| Clinical Pearls | Heparin sodium preservative-free is preferred for use in neonates, pregnant women, and patients with heparin allergy to avoid benzyl alcohol toxicity. Monitor activated partial thromboplastin time (aPTT) closely; goal aPTT typically 1.5-2.5 times control. Use with caution in patients with thrombocytopenia or risk of bleeding. Protamine sulfate is the reversal agent. For subcutaneous administration, inject into abdominal fat, rotating sites. Do not rub injection site. |
| Patient Advice | Avoid aspirin, NSAIDs, and other blood thinners unless prescribed by your doctor. · Report unusual bleeding or bruising, dark stools, or blood in urine immediately. · Do not take any new medications without consulting your healthcare provider. · Use a soft toothbrush and electric razor to minimize bleeding risk. · Carry a medical alert card indicating heparin use. · If you miss a dose, do not double the next dose; contact your doctor. |