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By Medifit Education


anti Coagulants



Anticoagulants are medicines that help prevent blood clots. They’re given to people at a high risk of getting clots, to reduce their chances of developing serious conditions such as strokes and heart attacks.

A blood clot is a seal created by the blood to stop bleeding from wounds. While they’re useful in stopping bleeding, they can block blood vessels and stop blood flowing to organs such as the brain, heart or lungs if they form in the wrong place.

Anticoagulants work by interrupting the process involved in the formation of blood clots. They’re sometimes called “blood-thinning” medicines, although they don’t actually make the blood thinner.




Anticoagulants are used if you’re at risk of developing blood clots that could potentially block a blood vessel and disrupt the flow of blood around your body.

This can lead to several serious conditions, including:


Strokes– where a blood clot restricts the flow of blood to your brain, causing brain cells to die and possibly resulting in permanent brain damage or death


Transient ischaemic attacks (TIAs) – also called “mini-strokes”, these have similar symptoms to a stroke, but the effects usually last less than 24 hours


Heart attacks – where a blood clot blocks a blood vessel supplying your heart, starving it of oxygen and causing chest pain and sometimes death


Deep vein thrombosis (DVT) – where a blood clot forms in one of the deep veins in your body, usually your legs, causing pain and swelling


Pulmonary embolism – where a blood clot blocks one of the blood vessels around the lungs, stopping the supply of blood to your lungs




Anticoagulants are medicines that prevent the blood from clotting as quickly or as effectively as normal. Some people call anticoagulants blood thinners. However, the blood is not actually made any thinner – it just does not clot so easily whilst you take an anticoagulant.

Anticoagulants are used to treat and prevent blood clots that may occur in your blood vessels. Blood clots can block blood vessels (an artery or a vein). A blocked artery stops blood and oxygen from getting to a part of your body (for example, to a part of the heart, brain or lungs). The tissue supplied by a blocked artery becomes damaged, or dies, and this results in serious problems such as a stroke or heart attack. A blood clot in a large vein, such as a clot in a leg vein (a deep vein thrombosis), can lead to serious problems. For example, it can lead to a clot that travels from the leg vein to the lungs (a pulmonary embolism).

Side effects

A possible side effect of anticoagulants is excessive bleeding (haemorrhage), because these medicines increase the time it takes for blood clots to form.

Some people also experience other side effects.

  • Excessive bleeding
  • Signs of excessive bleeding can include:
  • passing blood in your urine
  • passing blood when you poo or having black poo
  • severe bruising
  • prolonged nosebleeds (lasting longer than 10 minutes)
  • bleeding gums
  • vomiting blood or coughing up blood
  • sudden severe back pain
  • difficulty breathing or chest pain
  • in women, heavy or increased bleeding during your periods, or any other bleeding from your vagina

If you notice any severe or recurrent bleeding, seek medical attention immediately. Contact your GP or go to your nearest accident and emergency (A&E) department.

You should also seek immediate medical attention if you:

  • are involved in a major accident
  • experience a significant blow to the head
  • are unable to stop any bleeding

If you’re taking warfarin, you’ll have regular blood tests to check if you’re at a high risk of excessive bleeding by measuring how quickly your blood clots. If your blood clots too slowly, your dose may be increased.


Other side effects of anticoagulants vary depending on which medication you’re taking.

For a full list of potential side effects for your medicine, check the leaflet that comes with it.


  • diarrhoea or constipation
  • feeling and being sick
  • indigestion
  • dizziness
  • headaches
  • rashes
  • itchy skin
  • hair loss
  • jaundice (yellowing of the skin and whites of the eyes)

Speak to your GP or anticoagulant clinic if you have any persistent troublesome side effects. Contact them immediately if you develop jaundice.


By Medifit Education