Drugs used to treat disorders in which blood fails to clot normally
Fresh frozen plasma
Several types of disorder cause spontaneous internal bleeding or excessive bleeding after even minor injuries (see Bleeding disorders). These disorders are usually treated with drugs that promote blood clotting or slow the breakdown of existing clots.
What are the types?
The three main types of drug that are used to promote the formation of blood clots and to prevent or reduce abnormal bleeding are blood products, vitamin K, and antifibrinolytic drugs.
Normal blood clotting depends on the presence in the blood of certain proteins called clotting factors. People who lack one of these clotting factors (often due to an inherited disorder) may be given specific blood products, which are concentrated supplements of the missing protein. For example, a blood product called Factor VIII is needed for the treatment of the inherited bleeding disorder haemophilia (see Haemophilia and Christmas disease), in which a defective gene causes a deficiency of natural Factor VIII in the blood. Another blood product, fresh frozen plasma, is given to counteract abnormally prolonged or severe bleeding due to causes such as an excessive dose of anticoagulants (see Drugs that prevent blood clotting).
All blood products are administered intravenously, either in hospital or at home, and may be used regularly as a preventive treatment or given when abnormal bleeding occurs.
Some people experience side effects, including chills and fever, when being given blood products. These side effects may result from an allergic reaction.
This vitamin is essential for the production of several vital blood-clotting factors. Newborn babies (who are born with no stores of vitamin K) and people who are deficient in vitamin K may need a supplement, which is either given by injection or taken orally. Vitamin K is also used to reverse the effect of an excessive dose of oral anticoagulants. No side effects are known to be associated with its use.
These drugs may be used when bleeding is difficult to control, as may occur after surgery, or to reduce menstrual bleeding that is excessively heavy (see Menorrhagia). Antifibrinolytic drugs affect the clotting process of blood by slowing the breakdown of existing clots. The drugs may be injected or given by infusion into a vein if bleeding must be stopped urgently or may be taken orally for the treatment of menorrhagia. Side effects such as headaches, diarrhoea, nausea, and vomiting are sometimes experienced by people who are taking these drugs.
From the 2010 revision of the Complete Home Medical Guide © Dorling Kindersley Limited.
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