New oral anticoagulants (‘blood thinners’)
If you have an irregular heart beat called atrial fibrillation your blood should be thinned with an anticoagulant to stop clot formation in the heart and worse – allowing this to break off and causing a stroke.
Traditionally this has been performed by giving warfarin better known to the lay public as ‘rat poison’. The rat is encouraged to eat the warfarin and has a massive overdose of it and bleeds to death. (Incidently I have used this rat poison before and always wonder where rats actually die.
I have never seen them dead in the attic surrounded by a pool of fresh blood.) As humans we monitor the amount of warfarin that is needed to thin the blood to the correct level by checking blood tests regularly. This is reassuring for all concerned but inconvenient. Newer versions of oral anticoagulants have become available (dabigatran, rivaroxaban, apixaban) which are marketed on the fact that they do not need to be monitored because they give a steady blood thinning state.
Certainly the evidence that they are as good or better as warfarin is persuasive but unlike warfarin we lack the ability to reverse their blood thinning effect and some areremoved from the body through the kidneys. If the kidneys stop working then there can be a build up of the blood thinners with dangerous bleeding as a result. They are also very expensive in terms of drug cost (about £50 per month compared to £1 for warfarin). So should we be using them? The simple answer is yes but in selected individuals. We have endorsed all of the 3 new oral anticoagulants at Bedford but will choose primarily apixaban because of its safety profile.