[Anistreplase. Pharmacology and biological data].

Anistreplase is a second generation thrombolytic agent, an equimolecular streptokinase lys-plasminogen complex the active site of which is temporarily blocked by a p-anisoyle group. Acylation enables the drug to be administered as a bolus intravenous injection over 2 to 5 minutes, and it protects anistreplase against circulating inhibitors, hence a plasma elimination half-life of 90 minutes. Deacylation is slow and progressive (deacylation half-life: 105 minutes), and it begins as soon as the product is injected. It reduces the hypotensive effect of streptokinase, permits a prolonged action in the thrombus and limits the risk of reocclusion. Using lys-plasminogen increases the affinity of the drug for fibrin and potentiates its accumulation and retention in the thrombus. In vitro studies have shown that the affinity of anistreplase for fibrin is similar to that of t-PA. In doses used for myocardial infarction, anistreplase induces a pronounced fibrinogenolysis. The effectiveness of the drug has been demonstrated on numerous animal models and subsequently by clinical trials.