Dalteparin (Perioperative VTE Prophylaxis)

How it works

It binds antithrombin and accelerates inhibition of factor Xa (with relatively less effect on thrombin), reducing fibrin formation and clot propagation.

Prescribing in practice

• Bleeding is the principal risk, so observe strict timing relative to neuraxial (spinal or epidural) anaesthesia and catheter removal to avoid spinal haematoma, and balance prophylaxis timing against surgical bleeding risk.
• Reduce the dose and consider anti-Xa monitoring in significant renal impairment, as dalteparin is renally cleared and accumulates.
• Monitor for heparin-induced thrombocytopenia and avoid in active major bleeding or known hypersensitivity to heparins.

Monitoring

Monitor platelet count, renal function and for clinical signs of bleeding, using anti-Xa levels only in selected patients such as those with renal impairment.

Counselling the patient

• Report any unusual bruising, bleeding or black stools.
• Tell the team about any planned spinal or epidural procedure so timing can be managed safely.

Evidence & guidelines

Surgical VTE prophylaxis with low-molecular-weight heparin is supported by NICE NG89 and extensive randomised trial evidence.