| Structure/Class |
- Fibrinolytic drug –recombinant tissue plasminogen activator. Brand names are alteplase, reteplase and tenecteplase.
|
| Pharmacodynamics |
- Converts plasminogen to plasmin, which then breaks down fibrin.
- In theory, it activates plasminogen that is bound to fibrin, and is supposed to produce local fibrinolysis more so than systemic lysis.
|
| Absorption/administration |
- IV
|
| Distribution |
|
| Metabolism |
- Short half-life (cleared in the liver). As such, heparin must be used together as an adjunct.
|
| Excretion |
|
| Indications |
- Massive PE
- Ischaemic stroke, within 3/24 of symptoms.
- AMI
- DVT (severe)
- Possibly intra-arterial thrombus.
|
| Contraindications |
- Active bleeding
- Any condition predisposing to severe bleeding (severe HTN/recent surgery/GI ulcer)
|
| Interactions |
|
| Special precautions |
|
| Adverse effects |
Haemorrhage, either at the site of thrombus or systemic lysis state from the formation of plasmin à fibrinolysis and destruction of other coagulation factors. |
| Dosing/administration |
|
| Toxicology |
|
| Withdrawal states |
|
| Special notes |
- A note about the other fibrinolytic drugs:
- Streptokinase is a protein (and not an enzyme) synthesized by streptococci that combines with plasminogen and catalyses it to active plasmin.
- Urokinase is a human enzyme that is produced by the kidney that converts plasminogen to plasmin.
- Tenecteplase has a longer half-life, and therefore can be given as an IV push.
- A note about fibrinolytic inhibitors:
- Aminocaproic acid (EACA) is a competitive inhibitor of plasminogen activator. It can be administered orally or IV, and usually given as a bolus and then an infusion. It is cleared by the kidney. Tranexamic acid is an analog of EACA, with the same properties.
Clinical indications are haemophilia, bleeding from fibrinolytic therapy, and prophylaxis against re-bleeding from intracranial aneurysms. |
