| Reteplase, Retavase, r-PA
Reteplase is a second-generation recombinant tissue-type plasminogen activator that seems to work more quickly and to have a lower bleeding risk than the first-generation agent alteplase.
Reteplase is a synthetic nonglycosylated deletion mutein of tissue plasminogen activator containing 355 of the 527 amino acids of native tissue plasminogen activator. The drug is produced in Escherichia coli by recombinant techniques. Reteplase does not bind fibrin as tightly as native tissue plasminogen activator, allowing the drug to diffuse more freely through the clot rather than binding only to the surface the way tissue plasminogen activator does. In high concentrations, reteplase does not compete with plasminogen for fibrin-binding sites, allowing plasminogen at the site of the clot to be transformed into clot-dissolving plasmin. These 2 modifications help explain the faster clot resolution seen in patients receiving reteplase than in those receiving alteplase.
The modifications also resulted in a molecule with a faster plasma clearance and shorter half-life (about 11-19 min) than alteplase. Reteplase undergoes renal (and some hepatic) clearance. The shorter half-life makes the drug ideal for double-bolus dosing. The result is more convenient administration and faster thrombolysis with reteplase than with alteplase, which is given by a bolus followed by an intravenous (IV) infusion.
The agent may be readministered as necessary, as it is not antigenic and almost never is associated with any allergic manifestations.
Fantastic new books!
CAM Therapies has studies on natural therapies for over 100 diseases.
CAM Labs lists lab tests for 100 diseases.
Nutritional Genetics is a fantastic resource.