Medicines - blood clotting

Fibrinolytics / thrombolytics

• Fibrinolytics / thrombolytics are a group of medicines that are used to dissolve clots that have already formed. Medicines in this group include alteplase, reteplase, streptokinase and tenecteplase.
  
  
• They increase the action of plasmin, a substance in the blood that breaks up the strands of fibrin that bind blood clots together.
  
  
• Fibrinolytic medicines are normally given by intravenous injection (direct into a blood vessel).

Glycoprotein IIb / IIIa inhibitors

• Glycoprotein Ilb / IIIa inhibitors are a group of medicines which include abciximab, eptifibatide and tirofiban.
  
  
• They prevent the formation of blood clots by stopping the binding of fibrinogen to receptors on platelets.
  
  
• They will normally be taken with aspirin and heparin and will be given by intravenous injection.

Anticoagulants

• Anticoagulants prevent the formation of blood clots.
  
  
• Heparin is an anticoagulant which is given by intravenous injection. An anticoagulant, such as warfarin, which can be taken in tablet form is normally started at the same time. The use of heparin will usually be continued for at least five days, after which the oral anticoagulant may be continued.
  
  
• Oral anticoagulants are a group of medicines which include warfarin, acenocoumarol / nicoumalone and phenindione. It is very important that you take your anticoagulant therapy exactly as explained by your doctor as too high a dose may result in the blood being unable to clot when it should do, eg when you cut yourself.
  
  
• When you are first prescribed an anticoagulant, your doctor or pharmacist will supply you with a booklet about your medicine. You should carry this booklet around with you at all times so that other doctors will be aware that you are taking an anticoagulant if you are ever in an accident or have to go into hospital again.

Aspirin

• Aspirin is an anti-platelet medicine which can help to prevent blood from clotting inside the blood vessels.
  
  
• It reduces the ‘stickiness’ of platelets - the small blood cells that stick together to form a clot. This will help prevent clots forming in the small blood vessels around the heart and brain and help reduce the risk of having a heart attack or stroke.
  
  
• The dose of aspirin used in this situation is much lower than the dose used in pain relief, normally 75–300 mg a day.
  
  
• Aspirin is the most commonly prescribed anti-platelet medicine but there are other anti-platelet medicines available such as clopidogrel and ticlopidine.