How long to treat?
Many patients are put on warfarin for six months after a thromboembolic episode. This, however, must be working on the ‘just in case’ principle.
This article suggests that there is no good evidence available for continuing beyond three months.
It proposes that six weeks on warfarin is sufficient in uncomplicated cases.
This is important, not because warfarin is expensive, but because the consequential costs and inconveniences to the patient on anticoagulants are considerable.
Reading this abstract should give you the confidence to ask questions of your patient’s hospital management.
Why go there: food for thought.
Information from: Circulation.
Interactions with warfarin
Drug interactions with warfarin are always a concern for GPs. You have to warn the patient about the major concerns, but if a patient on anticoagulants presents with an intercurrent illness, we need to know all the minutiae of possible areas where trouble might be encountered.
This PDF includes useful information about initiating and maintaining anticoagulation. However, the main reason for recommending this site is so that you can go straight to the last page (page 8), where you will find the appendix number two.
This is a table that includes prescription drugs and OTC medicines that can cause interactions.
Perhaps the most useful these days, when so many patients seem to find the urge to take some untried and untested preparation from the health food shop in preference to asking expert advice, commonly consumed herbal medicines are also listed.
Why go there: print off this list and save time checking.
Downside: not 100 per cent comprehensive.
Information from: British Colombian Ministry of Health.
Address: www.healthservices.gov.bc.ca/msp/protoguides/gps/ warfarin_therapy.pdf
Warfarin therapy can be a cause of anxiety for patients, who cannot help but get the message that it is a potentially dangerous form of treatment.
It is impossible to prescribe anticoagulants without going through the interactions, precautions and warning signs of overdose.
It is also impossible for the patient to absorb all the dos and don’ts at one sitting.
A good, straightforward and clearly written factsheet is essential.
This site contains just the thing. It is downloadable and printable as a three-page PDF from this Scottish charity.
Why go there: a basic essential.
Information from: Chest, Heart and Stroke Scotland.
Dr Barnard is a former GP in Fareham, Hampshire
Clinical review on anticoagulation therapy, page 22
Website of the week
This site will prove useful to anyone considering setting up an anticoagulation service in primary care. It is written by Dr Alan Begg, who is a member of the RCGP (Scotland) Clinical Guidelines Working Group and a GP himself.
Anticoagulation monitoring is a national enhanced service and all aspects are covered here.
The components of an anticoagulation service are listed in a clear table and the importance of a computerised decision support system is emphasised.
Dr Begg concludes with some wise words, saying that practices considering anticoagulant monitoring need to consider how to maximise the benefits and convenience to patients.
This dissertation is on the eGuidelines website and you will need to register with your GMC number to gain access.
Why go there: hard to improve on this.
Information from: eGuidelines.