Thrombolytic drug
Encyclopedia
Thrombolytic drugs are used in medicine
to dissolve blood clots
in a procedure termed thrombolysis
. They limit the damage caused by the blockage of the blood vessel
.
(heart attack), thromboembolic strokes, deep vein thrombosis
and pulmonary embolism
to clear a blocked artery and avoid permanent damage to the perfused tissue (e.g. myocardium, brain
, leg
) and death
. A less frequent use is to clear blocked catheter
s that are used in long-term medical therapy.
Thrombolytic therapy in hemorrhagic strokes is contraindicated, as its use in that situation would prolong bleeding into the intracranial space and cause further damage.
These drugs are most effective if administered immediately after it has been determined they are clinically appropriate. The advantage of administration is highest within the first sixty minutes, but may extend up to six hours after the start of symptoms.
The drugs are often given in combination with intravenous heparin
, or low molecular weight heparin
, which are anticoagulant drugs.
). If the symptoms are mild, the infusion is stopped and the patient is commenced on an antihistamine
before infusion is recommenced. Anaphylaxis
generally requires immediate cessation of thrombolysis.
Medicine
Medicine is the science and art of healing. It encompasses a variety of health care practices evolved to maintain and restore health by the prevention and treatment of illness....
to dissolve blood clots
Thrombus
A thrombus , or blood clot, is the final product of the blood coagulation step in hemostasis. It is achieved via the aggregation of platelets that form a platelet plug, and the activation of the humoral coagulation system...
in a procedure termed thrombolysis
Thrombolysis
Thrombolysis is the breakdown of blood clots by pharmacological means. It is colloquially referred to as clot busting for this reason...
. They limit the damage caused by the blockage of the blood vessel
Blood vessel
The blood vessels are the part of the circulatory system that transports blood throughout the body. There are three major types of blood vessels: the arteries, which carry the blood away from the heart; the capillaries, which enable the actual exchange of water and chemicals between the blood and...
.
Uses
Thrombolysis is used in myocardial infarctionMyocardial infarction
Myocardial infarction or acute myocardial infarction , commonly known as a heart attack, results from the interruption of blood supply to a part of the heart, causing heart cells to die...
(heart attack), thromboembolic strokes, deep vein thrombosis
Deep vein thrombosis
Deep vein thrombosis is the formation of a blood clot in a deep vein. Deep vein thrombosis commonly affects the leg veins or the deep veins of the pelvis. Occasionally the veins of the arm are affected...
and pulmonary embolism
Pulmonary embolism
Pulmonary embolism is a blockage of the main artery of the lung or one of its branches by a substance that has travelled from elsewhere in the body through the bloodstream . Usually this is due to embolism of a thrombus from the deep veins in the legs, a process termed venous thromboembolism...
to clear a blocked artery and avoid permanent damage to the perfused tissue (e.g. myocardium, brain
Human brain
The human brain has the same general structure as the brains of other mammals, but is over three times larger than the brain of a typical mammal with an equivalent body size. Estimates for the number of neurons in the human brain range from 80 to 120 billion...
, leg
Human leg
The human leg is the entire lower extremity or limb of the human body, including the foot, thigh and even the hip or gluteal region; however, the precise definition in human anatomy refers only to the section of the lower limb extending from the knee to the ankle.Legs are used for standing,...
) and death
Death
Death is the permanent termination of the biological functions that sustain a living organism. Phenomena which commonly bring about death include old age, predation, malnutrition, disease, and accidents or trauma resulting in terminal injury....
. A less frequent use is to clear blocked catheter
Catheter
In medicine, a catheter is a tube that can be inserted into a body cavity, duct, or vessel. Catheters thereby allow drainage, administration of fluids or gases, or access by surgical instruments. The process of inserting a catheter is catheterization...
s that are used in long-term medical therapy.
Thrombolytic therapy in hemorrhagic strokes is contraindicated, as its use in that situation would prolong bleeding into the intracranial space and cause further damage.
Members
The thrombolytic drugs include:- tissue plasminogen activatorTissue plasminogen activatorTissue plasminogen activator is a protein involved in the breakdown of blood clots. It is a serine protease found on endothelial cells, the cells that line the blood vessels. As an enzyme, it catalyzes the conversion of plasminogen to plasmin, the major enzyme responsible for clot breakdown...
t-PA:
- alteplase (Activase)
- reteplaseReteplaseReteplase is a thrombolytic drug, used to treat heart attacks by breaking up the clots that cause them....
(Retavase) - tenecteplaseTenecteplaseTenecteplase is an enzyme used as a thrombolytic drug.Tenecteplase is a tissue plasminogen activator produced by recombinant DNA technology using an established mammalian cell line...
(TNKase) - anistreplaseAnistreplaseAnistreplase is a thrombolytic drug.Anistreplase has been developed by Beecham as Eminase. It is also known as anisoylated plasminogen streptokinase activator complex -Mechanism:...
(Eminase) - streptokinaseStreptokinaseStreptokinase , a protein secreted by several species of streptococci can bind and activate human plasminogen. SK is used as an effective and inexpensive thrombolysis medication in some cases of myocardial infarction and pulmonary embolism...
(Kabikinase, Streptase) - urokinaseUrokinaseUrokinase , also called urokinase-type plasminogen activator , is a serine protease . Urokinase was originally isolated from human urine, but is present in several physiological locations, such as blood stream and the extracellular matrix...
(Abbokinase)
These drugs are most effective if administered immediately after it has been determined they are clinically appropriate. The advantage of administration is highest within the first sixty minutes, but may extend up to six hours after the start of symptoms.
The drugs are often given in combination with intravenous heparin
Heparin
Heparin , also known as unfractionated heparin, a highly sulfated glycosaminoglycan, is widely used as an injectable anticoagulant, and has the highest negative charge density of any known biological molecule...
, or low molecular weight heparin
Low molecular weight heparin
In medicine, low-molecular-weight heparin is a class of medication used as an anticoagulant in diseases that feature thrombosis, as well as for prophylaxis in situations that lead to a high risk of thrombosis....
, which are anticoagulant drugs.
Side-effects
Hemorrhagic stroke is a rare but serious complication of thrombolytic therapy. If a patient has had thrombolysis before, an allergy against the thrombolytic drug may have developed (especially after streptokinaseStreptokinase
Streptokinase , a protein secreted by several species of streptococci can bind and activate human plasminogen. SK is used as an effective and inexpensive thrombolysis medication in some cases of myocardial infarction and pulmonary embolism...
). If the symptoms are mild, the infusion is stopped and the patient is commenced on an antihistamine
Antihistamine
An H1 antagonist is a histamine antagonist of the H1 receptor that serves to reduce or eliminate effects mediated by histamine, an endogenous chemical mediator released during allergic reactions...
before infusion is recommenced. Anaphylaxis
Anaphylaxis
Anaphylaxis is defined as "a serious allergic reaction that is rapid in onset and may cause death". It typically results in a number of symptoms including throat swelling, an itchy rash, and low blood pressure...
generally requires immediate cessation of thrombolysis.
See also
- thrombolysisThrombolysisThrombolysis is the breakdown of blood clots by pharmacological means. It is colloquially referred to as clot busting for this reason...
- anticoagulant drugs
- antiplatelet drugAntiplatelet drugAn antiplatelet drug is a member of a class of pharmaceuticals that decrease platelet aggregation and inhibit thrombus formation...
s - antiaggregants