Thrombolytic Agents Flashcards
Which medications are classified as thrombolytic agents?
- alteplase
- reteplase
- tenecteplase
- streptokinase
- urokinase
What are indications for treatment with thrombolytic agents?
- lysing thrombin during treatment of acute MI
- treatment of PE
- treatment of venous thrombosis
- to open occluded IV catheters
How do thrombolytic agents work?
- binds to fibrin and plasminogen and converts bound plasminogen to plasmin
What are disadvantages of urokinase and streptokinase?
- lack fibrin specificity
- induce a systemic lytic state
- Very expensive
How does major toxicity due to thrombolytic agents manifest?
- hemorrhage
- lysis of fibrin at sites of vascular injury
- systemic lytic state
- serious hemorrhage occurs in 2-4% of patients
- intracranial hemorrhage in 1% of patients
What post-therapy issues can occur with thrombolytic agents?
- fibrinolytic therapy can last for 7-24 hours after the medication is discontinued
- monitor fibrinogen concentrations or thrombin times
What are absolute contraindications for thrombolytic therapy?
- Active internal bleeding
- Recent TBI or CVA
- BP > 200/120
- Traumatic CPR
- Pregnancy
What are relative contraindications for thrombolytic therapy?
- Chronic severe HTN
- Active peptic ulcer disease
- Any other known bleeds
- Significant liver disease
- Used streptokinase previously (b/c forms antibodies)
What are both relative AND absolute contraindications for thrombolytic therapy?
- Trauma or surgery within 14 days (depends on the severity)
T/F
Streptokinase has no intrinsic enzymatic activity
True
This was underlined by Emily in the lecture (slide 71)
What is the MOA of streptokinase?
Forms a stable 1:1 complex with plasminogen causing CONFORMATIONAL changes that expose the active site that cleaves free plasminogen to plasmin.
What is the MOA of t-PA?
Binds to fibrin and plasminogen and converts bound plasminogen to plasmin.
Wha is the MOA of urokinase?
Two chain serine protease isolated from human kidney cells that converts plasminogen to plasmin.
If a patient had thrombolytic therapy, monitoring _____ level may be helpful for correcting potential hemostatic abnormalities before anticipated surgery or other invasive procedure.
fibrinogen
