COVID-19 – Warfarin

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The NHS Specialist Pharmacy Service have published a guide to Management of patients taking warfarin during the COVID-19 pandemic.

[See also: Guidance for Safe Switching of Warfarin to DOACs]

The guide recommends a stepwise approach:

  1. For patients with prior DVT or PE with low risk of recurrence, consider stopping warfarin.
  2. For other patients, consider switching to a DOAC – using a phased approach over a 12 week cycle to protect the supply chain, with priority for those with poor INR control.
  3. Seek specialist advice before switching people if any of the following apply:
        • active malignancy and/or chemotherapy
        • venous thrombosis at unusual sites
        • taking phenytoin, carbamazepine, phenobarbitone or rifapicin
        • dual antiplatelet plus warfarin triple therapy
  4. Where warfarin remains necessary (e.g.: prosthetic mechanical valve; consult cardiologist; moderate to severe mitral stenosis; antiphospholipid antibody syndrome; pregnant, breastfeeding or planning pregnancy; requires a higher INR; severe renal impairment; major drug interactions (e.g. HIV meds), consider options to minimise INR monitoring:
        • extend INR intervals
        • consider self-monitoring
        • community monitoring via phlebotomy services
        • self- or family/friend-supported-injection of LMWH