drugs used in bleeding disorders

Question 1

what is haemostasis

Answer 1

arrest of blood loss from damaged blood vessels and is essential to survival.

Question 2

what are the main phenomena (events) of haemostasis

Answer 2

platelet adhesion and activation and blood coagulation

Question 3

what is thrombosis

Answer 3

a pathological condition resulting from inappropriate activation of haemostatic mechanisms

Question 4

what is venous thrombosis usually associated with

Answer 4

stasis of blood; a venous thrombus has a small platelet component and a large component of fibrin.

Question 5

what is arterial thrombosis usually associated with

Answer 5

atherosclerosis, and the thrombus has a large platelet component

Question 6

Thrombotic and thromboembolic disease could result in:

Answer 6

Myocardial infarction
Stroke
Deep vein thrombosis
Pulmonary embolus

Question 7

what is thrombus

Answer 7

A clot that adheres to a vessel wall.

Question 8

what is embolus

Answer 8

A detached thrombus (floats in the blood) and may occlude blood vessels and deprive tissues of oxygen and nutrients

Question 9

Thrombosis in intact endothelium (without injury but can get it)

Answer 9

Platelets monitor the integrity of the endothelium.
In the absence of injury resting platelets circulate freely.
Nitric oxide and prostacyclin in intact endothelium act as inhibitors of platelet aggregation.
However, lower levels of prostacyclin leads to platelet aggregation.
Circulating levels of thrombin and thromboxanes are low in the intact blood vessel.
This means that platelet receptors for thrombin and thromboxanes are not occupied, thereby inhibiting platelet activation and aggregation.

Question 10

Thrombosis in injured endothelium

Answer 10

platelets adhere to the its lining.
Platelet activation triggers release of platelet granules containing mediators such as adenosine diphosphate (ADP), thromboxane A2 (TXA2), serotonin, platelet-activation factor (PAF) and thrombin.
These mediators bind to receptors on the membrane of resting platelets circulating nearby.
The resting platelets become activated, and they begin to aggregate. (clump together)

Question 11

The main drugs used thrombotic disorders are

Answer 11

Anticoagulants (act by targeting sudden points in the …)
Antiplatelet drugs (notably aspirin) (prevent platelets coming together)
Fibrinolytic drugs (dissolve clots)

Question 12

what do anticoagulants inhibit
what do they prevent

Answer 12

clot formation
formation of clots

Question 13

what do anticoagulants include

Answer 13

Injectable anticoagulants (heparin and newer thrombin inhibitors).
Oral anticoagulants (warfarin and related compounds)