Antiplatelets and Anticoagulants Flashcards
How does Streptokinase work?
Fibrinolytics
Bind and activate plasminogen
This produces Plasmin
Plasmin breaks down Fibrin which is a major constituent of thrombi
What are Fibrinolytics used for?
Acute MI
Pulmonary Embolism
Major Venous Thrombosis
What is the window of oppurtunity for Fibrinolytics in IHD and stroke?
12 hours for coronary occlusion
3 hours for ischaemic stroke
What breaks down a Thrombus?
Normally cleared by Plasmin (converted from Plasminogen)
What is the risk behind all Fibrinolytics?
Haemorrhage in the brain and GI tract
Why is it important that Fibrinolytics are given as soon as possible in MI?
To prevent myocardial necrosis
When should you NOT give Fibrinolytics?
Active peptic ulcer
History of cerebral haemorrhage
Uncontrolled hypertension
Who shouldn’t you give Streptokinase to?
Someone who has taken it in the past
If someone has a stroke after taking a Fibrinolytic, what should you check for?
CT/MRI to establish whether the cause is Haemorrhagic or not
What is the mechanism of action of Warfarin?
Inhibits Vitamin K dependent clotting factors
Clotting factors 2, 7, 9 and 10
How long does it take for Warfarin to start working?
A few days
What drugs interfere with the hepatic metabolism of Warfarin?
Aminodarone
Quinolone
Cimetidine
Alcohol
What interferes with platelet function in Warfarin?
Aspirin
What reduces vitamin k, affecting Warfarin action?
Cephalosporins
What are the main uses of Warfarin?
DVT
PE
AF
What are the ADRs of Warfarin?
Teratogenic
Bleeding/Bruising
What is reversal therapy of Warfarin?
Parenteral Vitamin K
Fresh frozen plasma
What is the mechanism of action of heparin?
Activates anti thrombin 3
This deactivates factors needed for clotting including factor 2a
How must Heparin be administered?
Parenterally (have poor GI absorption)
Heparin is used to to prevent thrombo-embolism. In which circumstances is it specifically used?
Peri-operatively Immobility DVT PE AF Acute coronary syndrome Pregnancy
What are common bleeding and bruising sites when using Heparin?
Intracranial
Injection sites
GI loss
Epistaxis
