ANTI-COAGULANTS

Anti-coagulants reduce blood clotting. Heparin has a short action. It is given by continuous IV infusion or by subcutaneous injection. Warfarin acts by antagonizing Vitamin K (necessary to synthesize clotting factors) and takes 36 to 48 hours to take effect.

Indications:

•  Deep vein thrombosis

•  Pulmonary embolus

•  To prevent embolic stroke

  •  In atrial fibrillation

  •  In valvular heart disease

  •  With arterial grafts or valve prostheses

  •  Following myocardial infarction

Patients with advanced cancer may require anti-coagulant therapy for a venous thrombosis or pulmonary embolus to control symptoms of pain or swelling. Treatment needs to be carefully monitored if there is co-existing liver damage. Treatment does not need to be continued for more than 3 to 4 weeks.

Warfarin is potentiated by certain drugs (including cimetidine, chlorpromazine, naproxen, chloramphenicol, allopurinol and aspirin), which may cause bleeding.

Occasionally patients are already taking long-term warfarin therapy when they enter hospice or palliative care. There may come a time when this therapy becomes inappropriate. It can be a difficult decision to stop treatment because the patient has usually been told by the hematologist that treatment must not be stopped. If the tumor itself is causing troublesome bleeding this is usually a clear indication to stop warfarin. If a terminally ill patient, after discussion with the doctor and nurse, is reluctant to stop warfarin altogether it can be reasonable to compromise by halving the dose and monitoring less frequently.

If a patient who is dying is still on warfarin there can be problems. IM injections of warfarin can cause large hematomas. There is a risk of gastrointestinal bleeding with altered blood coming from the mouth during and after death. This is very distressing for the relatives. If a patient is dying, warfarin can be reversed with Vitamin K. Oral phytonadione 10mg is effective within 4 hours. By IV injection (given slowly to avoid nausea) phytonadione takes almost immediate effect. (see Bleeding, Terminal Phase)

The author and publisher have taken precautions to ensure that the information in this book is error-free. However, readers must be guided by their own personal and professional standards of good practice in evaluating and applying recommendations made herein. The contents of this book represent the views and experience of the author, and not necessarily those of the publisher.