Formulary
Heparin: Indications, Dosing, Side Effects and Interactions
Heparin is an anticoagulant that enhances the effect of antithrombin III, which inhibits thrombin and activated factor X (factor Xa).
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Heparin: Indications, Dosing, Side Effects and Interactions
Heparin is an anticoagulant that enhances the effect of antithrombin III, which inhibits thrombin and activated factor X (factor Xa).
Drug action
Heparin is an anticoagulant that enhances the effect of antithrombin III, which inhibits thrombin and activated factor X (factor Xa).
Indications and dose
**Thromboprophylaxis in medical patients**
- **Adult** (By Subcutaneous Injection): 5000 units every 8-12 hours.
**Thrombophylaxis in surgical patients**
- **Adult** (By Subcutaneous Injection): 5000 units for 1 dose, to be taken 2 hours before surgery, then 5000 units every 8-12 hours.
**Thromboprophylaxis during pregnancy**
- **Adult** (By Subcutaneous Injection): 5000-10 000 units every 12 hours, to be administered with monitoring, Important : prevention of prosthetic heart-valve thrombosis in pregnancy calls for specialist management .
**Prevention of clotting in extracorporeal circuits for heparin**
- **Child** (To the device as a flush): (consult product literature).
**Maintenance of neonatal umbilical arterial catheter for heparin**
- **Neonate** (): 0.5 unit/hour.
**Treatment of thombotic episodes for heparin**
- **Neonate up to 35 weeks corrected gestational age** (Initially by intravenous injection): Initially 50 units/kg for 1 dose, then (by continuous intravenous infusion) 25 units/kg/hour, dose adjusted according to APTT.
- **Neonate** (Initially by intravenous injection): Initially 75 units/kg for 1 dose, then (by continuous intravenous infusion) 25 units/kg/hour, dose adjusted according to APTT.
- **Child 1-11 months** (Initially by intravenous injection): Initially 75 units/kg for 1 dose, then (by continuous intravenous infusion) 25 units/kg/hour, dose adjusted according to APTT.
- **Child 1-17 years** (Initially by intravenous injection): Initially 75 units/kg for 1 dose, then (by continuous intravenous infusion) 20 units/kg/hour, dose adjusted according to APTT.
- **Child** (By subcutaneous injection): 250 units/kg twice daily, dose adjusted according to APTT.
**Prophylaxis of thrombotic episodes for heparin**
- **Child** (By subcutaneous injection): 100 units/kg twice daily (max. per dose 5000 units), dose adjusted according to APTT.
**Maintenance of cardiac shunts and critical stents for heparin**
- **Child** (To the device as a flush): (consult local protocol).
Cautions
Elderly; risk of bleeding; severe hypertension
Contraindications
Acute bacterial endocarditis; after major trauma; avoid injections containing benzyl alcohol in neonates; epidural anaesthesia with treatment doses; haemophilia or other haemorrhagic disorders; peptic ulcer; recent cerebral haemorrhage; recent surgery to eye; recent surgery to nervous system; spinal anaesthesia with treatment doses; thrombocytopenia (including history of heparin-induced thrombocytopenia)
Side effects
Common or very common Haemorrhage; heparin-induced thrombocytopenia; skin reactions Rare or very rare Alopecia; hyperkalaemia; osteoporosis (following long term use); spinal haematoma Side-effects, further information Haemorrhage If haemorrhage occurs it is usually sufficient to withdraw heparin or a low molecular weight heparin, but if rapid reversal of the effects of the heparin is required, protamine sulfate is a specific antidote (but only partially reverses the effects of low molecular weight heparins). Heparin-induced thrombocytopenia Clinically important heparin-induced thrombocytopenia is immune-mediated and can be complicated by thrombosis. Signs of heparin-induced thrombocytopenia include a 30% reduction of platelet count, thrombosis, or skin allergy. If heparin-induced thrombocytopenia is strongly suspected or confirmed, the heparin should be stopped and an alternative anticoagulant, such as danaparoid, should be given. Ensure platelet counts return to normal range in those who require warfarin. Hyperkalaemia Inhibition of aldosterone secretion by heparin or a low molecular weight heparin can result in hyperkalaemia; patients with diabetes mellitus, chronic renal failure, acidosis, raised plasma potassium or those taking potassium-sparing drugs seem to be more susceptible. The risk appears to increase with duration of therapy. Side-effects For heparin Frequency not known Adrenal hypofunction; hypokalaemia; priapism; rebound hyperlipidaemia; thrombocytopenia
Interactions
**Other interactions (3):**
- The anticoagulant effect of heparin may be enhanced by concomitant administration of other drugs affecting the coagulation system, such as those inhibiting platelet function (e.g.
- Combined use with ACE inhibitors or angiotensin II antagonists may increase the risk of hyperkalaemia; however, this interaction has not been recorded for Heparin LEO.
- Use of glyceryl trinitrate infusion may reduce the anticoagulant effect of heparin.
Pregnancy
Thromboprophylaxis during pregnancy for heparin By subcutaneous injection Adult 5000-10 000 units every 12 hours, to be administered with monitoring, Important : prevention of prosthetic heart-valve thrombosis in pregnancy calls for specialist management .
Breast feeding
Not excreted into milk due to high molecular weight.
Hepatic impairment
Manufacturer advises caution; consider avoiding in severe impairment (increased risk of bleeding complications). Dose adjustments Manufacturer advises consider dose reduction if used in severe impairment.
Renal impairment
Use with caution. M Dose adjustments Consider dose reduction in severe impairment (increased risk of bleeding). M
Medicinal forms
Solution,Solution
Clinical governance
**Author:** MedNext Clinical Team. **Clinical reviewer:** Dr Shameer Deen, MBBS, MS, MRCS. **Sources:** BNF, Indian Pharmacopoeia, CIMS India. **Correction:** Report errors at support@mednext.academy.
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