Anticoagulants are used to prevent the blood from clotting; blood clots can contribute to serious health conditions including strokes and heart attacks as they block the free flow of the blood around the body. The most commonly used anticoagulants include warfarin and heparin.

Who is prescribed anticoagulant medication?

Anticoagulants are predominantly given to people that are at risk of suffering from conditions caused by blood clots, including deep vein thrombosis, strokes and heart attacks; high risk groups include:

  • People over the age of 65
  • People with African or Caribbean heritage
  • People who have high cholesterol and high blood pressure
  • People that are very overweight or obese

How do anticoagulants work?

Anticoagulants work by disrupting the process which causes blood clots to form; this means clots still form when they are needed but are less likely to form when they are not needed.

Special considerations

If you are taking anticoagulant medication and are due to undergo surgery, you should inform the healthcare team that you are taking anticoagulants. It is important to stick to the dosage recommended by your doctor; if you take too much or too little, this could have serious implications for your health. If you are taking other medications, you should discuss this with your doctor as taking anticoagulants with other medications may cause some medicines to work less effectively.

Are there any side-effects?

A common side-effect of taking anticoagulants is bleeding; this is because the medication makes it take longer for clots to form. If you experience any of the following symptoms you should seen urgent medical help:

  • Passing blood in your faeces or urine
  • Coughing up blood
  • Passing black faeces
  • Nosebleeds that last for longer than 10 minutes
  • Breathing difficulties
  • Severe bruising
  • Traces of blood in your vomit

If you are put on anticoagulant medication, your condition will be monitored closely and you will be advised to see your doctor on a regular basis.

Guide to Medication






Contraceptive medication

Beta blockers