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Thrombolytic Drugs

A group of drugs, also known as fibrinolytics, used to dissolve blood clots

Common drugs

  • Alteplase

  • Reteplase

  • Streptokinase

  • Tenecteplase

Thrombolytic drugs act rapidly to dissolve unwanted blood clots (thrombi) in blood vessels. They are most commonly given as an emergency treatment for heart attacks (see Myocardial infarction) or for certain types of stroke and can significantly increase a person’s chance of survival.

A heart attack is usually caused by a blood clot blocking one of the coronary arteries, which supply blood to the heart muscle. Left untreated, such a clot can cause irreversible damage to the heart, which can be fatal. Strokes are usually caused by a blood clot blocking the supply of blood to an area of the brain.

Thrombolytics may be used to dissolve a blood clot in a vein deep within the body, often in the legs (see Deep vein thrombosis). These fast-acting drugs may also be used to treat pulmonary embolism.

Thrombolytic drugs work by dissolving the mesh of fibrin, a stringy protein that binds a blood clot together (see How thrombolytic drugs work). When the blood clot has been dissolved by the drugs, normal blood flow to the affected area is restored.

How are they used?

Thrombolytics are given by injection or by infusion. In the treatment of a heart attack, the drugs must be given within 6–12 hours (ideally, within 1 hour) of the start of the attack to be effective. In the case of a stroke, the drugs must be given within 3 hours (ideally, within 1 hour) of the onset of symptoms.

These drugs may cause side effects such as nausea and vomiting, as well as an increased susceptibility to bruising and bleeding. Streptokinase, which is one of the most frequently used thrombolytics, can cause allergic reactions, often in the form of a rash. Occasionally, a life-threatening allergic reaction called anaphylaxis occurs.

Drug Action: How Thrombolytic Drugs Work

From the 2010 revision of the Complete Home Medical Guide © Dorling Kindersley Limited.

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