Alteplase (tPA) is used as a thrombolytic. It preferentially acts on plasminogen bound to fibrin rather than circulating free plasminogen. This property confers which clinical advantage?

• A Relative fibrin specificity, producing clot lysis with less systemic plasmin generation and theoretically less systemic hemorrhagic risk compared to streptokinase ✓
• B Longer half-life allowing single-dose administration
• C Ability to lyse older organized thrombi unresponsive to streptokinase
• D Reduced antigenicity compared to streptokinase, allowing repeat dosing

Explanation

Alteplase (recombinant tPA) has a fibrin-binding domain (finger domain) that directs it preferentially to fibrin-bound plasminogen at the clot, generating localized fibrinolysis. Systemic plasminogen activation is less pronounced, theoretically reducing systemic fibrinogenolysis and bleeding risk. Streptokinase forms a complex with circulating plasminogen and causes widespread systemic plasmin activation, fibrinogenolysis, and immunogenicity (cannot be repeated). However, clinically, intracranial hemorrhage rates are similar. Alteplase is the preferred agent for acute ischemic stroke and massive PE.

Reference: KD Tripathi, Essentials of Medical Pharmacology, 8th ed.

High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP

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