Heparin
Mechanism :
Heparin is a heterogeneous group of straight-chain anionic mucopolysaccharides, called glycosaminoglycans having anticoagulant properties. Heparin inhibits reactions that lead to the clotting of blood and the formation of fibrin clots. Heparin acts at multiple sites in the normal coagulation system, in combination with antithrombin III it can inhibit thrombosis by inactivating activated Factor X and inhibiting the conversion of prothrombin to thrombin.
Indication :
- Thromboembolic disease
- Maintain IV-line/catheter patency
- Thrombosis
- ECMO
Contraindications :
Contraindicated in patients with severe thrombocytopenia, this contraindication refers to full-dose heparin; there is usually no need to monitor coagulation parameters in patients receiving low-dose heparin sodium. Contraindicated in patients with an uncontrollable active bleeding state, except when this is due to disseminated intravascular coagulation.
Dosing :
Thromboembolic disease and ECMO:
IV infusion:
75 units/kg given IV as a loading dose and initially maintained on 28 units/kg/hour in children <1 year and maintenance of 20 units/kg/hour in children >1 years.
Intermittent injection:
Start with 50-100 units/kg IV and maintain on 100 units/kg given IV every 4 hourly.
Catheter patency:
For infants <10 kg:
10 units/ml; instill sufficient volume so that lumen of catheter is filled.
For children and infants >10 kg:
10-100 units/ml; instill sufficient volume so that lumen of catheter is filled.
Adverse Effect :
Hemorrhage, skin necrosis, heparin-induced thrombocytopenia, hyperkalemia, osteoporosis and hypersensitivity reactions.
Interaction :
Oral Anticoagulants: Heparin sodium may prolong the one-stage prothrombin time
Acetylsalicylic acid, dextran, phenylbutazone, ibuprofen, indomethacin, dipyridamole, hydroxychloroquine: May induce bleeding and should be used with caution in patients receiving heparin sodium.
Digitalis, Tetracyclines, Nicotine, or Antihistamines: May partially counteract the anticoagulant action of heparin sodium.
Renal Dose :
Dose in Renal Impairment GFR (mL/min)
20-50 | Dose as in normal renal function |
10-20 | Dose as in normal renal function |
<10 | Dose as in normal renal function |
Dose in Patients undergoing Renal Replacement Therapies
CAPD | Not dialysed. Dose as in normal renal function |
HD | Not dialysed. Dose as in normal renal function |
HDF/High flux | Not dialysed. Dose as in normal renal function |
CAV/VVHD | Not dialysed. Dose as in normal renal function |
Hepatic Dose :
No dosage adjustments are recommended.