Thrombolytic drugs are used in medicine to dissolve blood clots in a procedure termed thrombolysis. They limit the damage caused by the blockage or occlusion of a blood vessel.
Thrombolytic agents are used for the treatment of myocardial infarction (heart attack), thromboembolic strokes, deep vein thrombosis and pulmonary embolism to clear a blocked artery and avoid permanent damage to the perfused (see perfusion) tissue (e.g. myocardium, brain, leg) and death. They may also be used 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.
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 after a thrombotic event, but may extend up to six hours after the start of symptoms.
These drugs are often administered in combination with anticoagulant drugs such as intravenous heparin or low molecular weight heparin, for synergistic antithrombotic effects and secondary prevention.
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.
- Anticoagulant drugs
- Antiplatelet drugs