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19 Cards in this Set
- Front
- Back
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Pregnancy category for all heparins
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Category C
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Heparins in breastfeeding?
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safe to use
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What is a rare but serious ADR of heparin & LMWH?
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Severe thrombocytopenia
- Immune-mediated thrombocytopenia occurs in <1% of patients with short-term use - can result in major ischaemic complications (eg stroke, limb ischaemia), bleeding or death |
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Management of HIT?
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- Withhold heparin or LMWH if platelet count drops 30–50% below baseline & substitute alternative anticoagulant.
- future use of heparin or LMWH is contraindicated if heparin-induced thrombocytopenia (HIT) is confirmed |
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Onset of HIT?
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- Severe HIT typically occurs between days 5 and 10 of treatment but may occur earlier if patient has been recently (<100 days) exposed to heparin.
- Delayed onset HIT has also occurred up to several weeks after stopping heparin. |
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What should you avoid to reduce the risk of HIT when using enoxaparin (Clexane)?
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avoid using heparinised saline to maintain patency of peripheral venous cannulae because it is no more effective than sodium chloride 0.9% flushes
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When should you consider IV heparin over SC enoxaparin?
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if an invasive procedure is anticipated as the anticoagulant effect diminishes more quickly after stopping enoxaparin
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Clexane formulations?
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20
40 60 80 100 mg Clexane Forte 120 & 150 mg |
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Enoxaparin (Clexane) dose for TREATMENT of VTE
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1 mg/kg BD or 1.5 mg/kg OD for 5–10 days
(Use BD dose for high-risk patients eg. in malignancy) If CrCl <30 mL/minute: 1 mg/kg OD |
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Enoxaparin (Clexane) dose for PREVENTION of VTE in surgical patients
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Moderate risk: 20 mg OD for 7–10 days or until mobilised, starting 2 hours before surgery.
High risk: 40 mg OD for 7–10 days or until mobilised, starting 12 hours before surgery. May be continued up to 30 days after total hip replacement |
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what electrolyte disturbance do heparins cause?
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hyperkalemia
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What is the relative bleeding incidence between heparin & LMWHs?
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Bleeding incidence is similar for heparin and LMWHs.
Protamine is only partially effective in reversing over-anticoagulation with LMWHs. In renal impairment: risk of severe bleeding is higher with LMWHs |
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what is an ADR associated with long term therapeutic use of heparin/LMWH?
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osteoporosis
(heparin > LMWH) |
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What is the relative incidence of HIT between heparin & LMWHs?
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Severe HIT incidence is lower with LMWHs than with heparin but LMWHs should not be used as an alternative to heparin in HIT because cross-reactivity occurs in 90% of cases
- danaparoid sometimes used for tx of HIT due to lower incidence |
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Predisposing factors for VTE
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elderly
acute infection acute heart failure respiratory insufficiency cancer |
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what is used in the prevention of VTE in general surgery?
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heparin and LMWHs have similar efficacy in preventing VTE
LMWHs have a longer half-life (3–6 hours) than heparin (60 minutes), require only once daily administration but cost more |
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what is used in the prevention of VTE in orthopedic surgery?
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LMWHs are more effective than heparin or warfarin
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Monitoring for heparin/LMWH
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Monitor platelet count on days 0, 3 and 5, then on alternate days
Heparin - Monitor APTT (1.5-2.5x) LMWH - Monitor antifactor Xa in patients at high risk of bleeding or showing toxicity (eg. multiple trauma, renal impairment, cancer, thin or obese patients, pregnant women) |
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What is the heparin dose for prevention of VTE in general surgery?
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5000 units 2 hours before procedure, then 5000 units 2 or 3 times daily for 7–10 days or until mobilised
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