Dalteparin, Enoxaparin, Tinzaparin
Issues for Surgery
Increased risk of venous thromboembolism if omitted.
Increased risk of bleeding if continued.
Increased risk of spinal haematoma in patients receiving neuraxial anaesthesia if continued.
Advice in the Perioperative period
Check serum potassium levels and platelet count pre-operatively (see Further Information).
Figure 1 – timing of administration of prophylactic LMWH prior to surgery
Figure 2 – timing of administration of therapeutic LMWH prior to surgery
* if possible (to minimise the time between last dose and operation whilst still allowing for reasonable anticoagulation coverage), consider bringing the treatment dose forward by a few hours each day over a number of days prior to surgery until patient is administering at 8am in the morning and follow advice for once daily administration in the morning (before 8am).
If there is insufficient time to follow the advice for elective surgery, and rapid reversal of the effects of LMWH are required, protamine sulfate is a specific antidote (but only partially reverses the effects)1, 2 – discuss with Haematologist.
Perioperative Considerations (see also Further Information)
Neuraxial (Spinal/Epidural) Anaesthesia or Lumbar Punctures – Prophylactic Doses
Insertion or removal of the catheter should be performed 12 hours after the last dose of LMWH3, 4, 5, 6, 7, 8. Once a catheter has been inserted, the next dose of LMWH should be administered a minimum of 4 hours post-insertion1, 8.
Neuraxial (Spinal/Epidural) Anaesthesia or Lumbar Punctures – Therapeutic Doses
Once a catheter has been removed, LWMH administration (prophylactic and treatment doses) can resume 4 hours after removal and in the presence of adequate haemostasis9.
Treatment Doses (If to be continued Post-op)
Monitor serum potassium, especially with prolonged use (> 7 days) – see Further Information.
Monitor platelet count, especially with prolonged use – see Further Information.
Monitor renal function – dose adjustment may be necessary if there is a decline in renal function (consult product literature).
Interaction(s) with Common Anaesthetic Agents
Interaction(s) with other Common Medicines used in the Perioperative Period
Hyperkalaemia (see also Further Information)
Both LMWH and trimethoprim can increase the risk of hyperkalaemia1.
Enhanced Anticoagulant Effect
The UK manufacturer of dalteparin advises that because heparin interacts with high doses of penicillin increasing the risk of haemorrhage2, 4, 9, an interaction with dalteparin cannot be ruled out. The clinical relevance is unclear but bear the potential interaction in mind in case of any unexpected outcome with concurrent use9. This predicted interaction is not cautioned with enoxaparin or tinzaparin5, 6.
Reduced Anticoagulant Effect
The UK manufacturer of dalteparin advises that the anticoagulant effect might be reduced by cyclizine4, 9.
They UK manufacturer of enoxaparin states that systemic corticosteroids affect haemostasis5, hence may reduce the anticoagulant effect. This interaction is not noted with dalteparin or tinzaparin4, 6.
Timing of Pre-operative Doses of Prophylactic LMWH
Treatment doses are contraindicated in patients who receive neuraxial anaesthesia due to the risk of spinal haematoma1, 4, 5, 6.
Thrombocytopenia and Heparin-induced Thrombocytopenia (HIT)