Thrombolytic drug

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.

Uses

Thrombolysis is used in myocardial infarction (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 catheters 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.

Condition	Prothrombin time	Partial thromboplastin time	Bleeding time	Platelet count
Vitamin K deficiency or warfarin	prolonged	normal or mildly prolonged	unaffected	unaffected
Disseminated intravascular coagulation	prolonged	prolonged	prolonged	decreased
von Willebrand disease	unaffected	prolonged	prolonged	unaffected
Hemophilia	unaffected	prolonged	unaffected	unaffected
Aspirin	unaffected	unaffected	prolonged	unaffected
Thrombocytopenia	unaffected	unaffected	prolonged	decreased
Liver failure, early	prolonged	unaffected	unaffected	unaffected
Liver failure, end-stage	prolonged	prolonged	prolonged	decreased
Uremia	unaffected	unaffected	prolonged	unaffected
Congenital afibrinogenemia	prolonged	prolonged	prolonged	unaffected
Factor V deficiency	prolonged	prolonged	unaffected	unaffected
Factor X deficiency as seen in amyloid purpura	prolonged	prolonged	unaffected	unaffected
Glanzmann's thrombasthenia	unaffected	unaffected	prolonged	unaffected
Bernard-Soulier syndrome	unaffected	unaffected	prolonged	decreased or unaffected

Members

The thrombolytic drugs include:

• tissue plasminogen activator t-PA:

• alteplase (Activase)
• reteplase (Retavase)
• tenecteplase (TNKase)

• anistreplase (Eminase)
• streptokinase (Kabikinase, Streptase)
• urokinase (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, or low molecular weight heparin, 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 streptokinase). 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.

See also

• thrombolysis
• anticoagulant drugs
• antiplatelet drugs
• antiaggregants

References