BLOOD THINNING MEDICATION – Should we all be taking it? by Dr John Grant


Low dose daily ASPIRIN is currently widely prescribed and is also often taken as a self-prescribed medication by many people. (Commonly taken as Ecotrin, Bayer Aspirin Cardio, Disprin CV)

The action of aspirin is to interfere with a part of the blood clotting system and to slow the blood clotting. This can be valuable in people who have damaged arteries where excessive blood clots tend to block the circulation.


Aspirin has two main benefits.

1.)      It significantly reduces the risk of heart attack or stroke in people over the age of 50 and in particular those  who have an increased risk of blood vessel damage due to;    coronary heart disease, stroke,  high blood pressure, high cholesterol, diabetes, overweight, cigarette smoking.

2.)      A recent study published in the LANCET (a prestigious British medical journal), showed that  taking low dose ASPIRIN over a five year period reduced the cancer death risk by 37 %. This particularly applied to colon cancer and breast cancer.

Please note that taking low dose ASPIRIN every day carries a RISK and is not for everyone. You should always discuss its use with your Doctor.

Aspirin carries an increased risk of bleeding especially from the stomach, so the following people should not be taking it.

•        Those with Aspirin allergy or sensitivity (this may include many asthmatics).

•        Those with a past history of peptic (stomach) ulcers, particularly with bleeding.

•        Those taking other anti-coagulant drugs – this must be discussed with your Doctor.

Please note to STOP taking your daily low-dose ASPIRIN if you are about to undergo any surgery or dental surgery as the risk of bleeding is greatly increased. Patient should stop their ASPIRIN at least 5 days prior to surgery.



Warfarin (Coumadin) is an anti-coagulant medication that is commonly prescribed to many of our patients. It has 2 main indications.

1.)  To prevent STROKE in patients with ATRIAL FIBRILLATION (AF). This is a condition which becomes increasingly common as one grows older. It is an abnormal heart rhythm where the heart beats very irregularly (the rhythm is said to be “irregularly irregular”).

This irregular heart rhythm carries with it a FIVE FOLD increase in the common kind  of  stroke (embolic), so all patients with AF should be on anticoagulation as this significantly reduces the risk of stroke.

2.)  To Prevent DEEP VEIN THROMBOSIS (DVT) in those patients who have a current or have  had a previous DVT.  DVT carries with it a high risk of pulmonary embolism (a piece of clot breaks off from within a thrombosed deep vein and then lodges in the lung) which can be life threatening.

Although WARFARIN has been used for over 50 years, its use remains problematic.        The action of warfarin is influenced by many factors including diet and other medication.  The dose needs to be constantly monitored to prevent overdosing and the risk of excessive bleeding. Patients have to go for a monthly INR (International Normalized Ratio) blood test to make sure that they are adequately dosed and not either over or under dosed.

Warfarin carries a significantly increased risk of bleeding, especially from the stomach and gastro-intestinal tract. It has numerous drug interactions so one has to be very careful which drugs are co-prescribed with it. It interacts with different foods and over the counter so-called natural drugs, e.g. ST JOHN’S WORT. Numerous studies have shown that only 50% of patients remain in the therapeutic range while taking WARFARIN. So this is a drug that is not ideal.

Luckily a new class of drug has become available – the NOAC’s (NOVEL ORAL ANTI –COAGULANTS) There are two currently available in South Africa.

1.)  PRADAXA (DABIGATRAN) – seems to be favoured by the cardiologists for the treatment of AF.

2.)   XARELTO (RIVAROXABAN) – seems to be favoured by the surgeons for the treatment of DVT.

These new oral anti-coagulants are easy to take and are as effective as WARFARIN but carry much lower risk of inadequate dosing or of excessive dosing and bleeding. Their downside is COST but, if you are having problems with WARFARIN, please speak to your doctor about these alternatives.