Which agent is less specific for fibrin, alteplase or tenecteplase?

Alteplase is less specific for fibrin compared to tenecteplase. Both agents are tissue plasminogen activators (tPAs) that facilitate the conversion of plasminogen to plasmin, leading to the breakdown of fibrin in blood clots. However, alteplase has a broader range of action; it can activate plasminogen in the circulation as well as at the clot site, which means it may lead to a higher risk of systemic fibrinogenolysis, thus dissolving fibrin in areas beyond the target clot.

Tenecteplase, on the other hand, has been engineered to have increased specificity for fibrin. Its design allows it to preferentially activate plasminogen that is bound to fibrin, thus limiting its effect to the clot rather than affecting circulating plasminogen significantly. This property helps to minimize bleeding risks associated with fibrinolytic therapy.

As a result, when considering their effects, alteplase is less specific for fibrin than tenecteplase, ultimately making it the correct choice to identify as the less specific agent in this context.