What is the classification of thrombolytic (fibrinolytic) agents?

From the Guidelines

Thrombolytic (fibrinolytic) agents can be classified into two main categories: fibrin-specific and non-fibrin-specific agents.

Classification of Thrombolytic Agents

• Fibrin-specific agents: These agents have a high degree of specificity for fibrin and are less likely to cause systemic bleeding. Examples of fibrin-specific agents include:
  • Tenecteplase (TNK-tPA) 1
  • Reteplase (rPA) 1
  • Alteplase (tPA) 1
• Non-fibrin-specific agents: These agents have a lower degree of specificity for fibrin and are more likely to cause systemic bleeding. Examples of non-fibrin-specific agents include:
  • Streptokinase 1
  • Urokinase 1

Mechanism of Action

Thrombolytic agents work by converting plasminogen to plasmin, which then breaks down fibrin clots 1. Fibrin-specific agents, such as tenecteplase and alteplase, have a higher affinity for fibrin and are more effective at breaking down clots with less systemic bleeding 1.

Clinical Use

The choice of thrombolytic agent depends on the specific clinical situation and the patient's individual characteristics 1. For example, tenecteplase is often used in patients with acute ischemic stroke due to its high fibrin specificity and longer half-life 1.

From the Research

Classification of Thrombolytic Agents

Thrombolytic agents can be classified into different generations based on their mechanism of action and fibrin specificity. The main classes of thrombolytic agents include:

• First-generation agents:
  • Streptokinase
  • Urokinase These agents are non-fibrin specific and can cause systemic fibrinogenolysis, leading to bleeding complications 2, 3, 4, 5.
• Second-generation agents:
  • Tissue-type plasminogen activator (t-PA)
  • Single-chain urokinase-type plasminogen activator (scu-PA or pro-urokinase)
  • Anisoylated plasminogen streptokinase activator complex (APSAC) These agents are more fibrin-specific than the first-generation agents, but may still cause systemic activation of the fibrinolytic system 2, 3, 4, 5.
• Fibrin-specific plasminogen activators:
  • Tissue-type plasminogen activator (t-PA)
  • Single-chain urokinase-type plasminogen activator (scu-PA)
  • Staphylokinase (Sak) These agents preferentially activate fibrin-associated plasminogen, reducing the risk of systemic fibrinolysis and bleeding complications 6.

Mechanism of Action

Thrombolytic agents work by converting plasminogen to plasmin, which then degrades fibrin and breaks down blood clots. The mechanism of action of these agents involves the activation of the plasminogen-plasmin system, which can be either fibrin-specific or non-fibrin specific 2, 3, 4, 5, 6.