Presentation on theme: "Drugs for Coagulation Disorders 20. 1. Explain the importance of hemostasis. 2. Construct a flow chart diagramming the important steps of hemostasis and."— Presentation transcript:
Drugs for Coagulation Disorders 20
1. Explain the importance of hemostasis. 2. Construct a flow chart diagramming the important steps of hemostasis and fibrinolysis. 3. Describe the types of disorders for which coagulation modifier drugs are prescribed. 4. Identify the primary mechanisms by which coagulation modifier drugs act.
5. For each of the classes in the Drug Snapshot, identify representative drugs, explain their mechanisms of action, primary actions, and important adverse effects. 6. Categorize coagulation modifier drugs based on their classifications and mechanisms of action.
Hemostasis is a complex process involving multiple steps and many clotting factors. Hemostasis is the balance between clot formation and clot breakdown
Everyone is familiar with simple cuts and scraps and we all take for granted that they will stop bleeding in a few minutes.
This process normally takes about 6 minutes Vitamin K is required for the liver to produce these clotting factors Liver disease can greatly effect coagulation
Removing a blood clot is essential to restoring normal circulation.
Once a stationary clot forms (thrombus), it often grows larger as more fibrin is added. Pieces of the clot may break off and travel in the blood stream to possibly lodge elsewhere. A traveling clot is know as an embolus When clots or emboli form, drug therapy becomes necessary.
Drugs are used to modify the coagulation process.
Anticoagulants used to prevent the formation of clots › Inhibit specific clotting factors in the coagulation cascade or diminish the clotting action of platelets › Increase the normal time the body takes to form clo ts
This is an incorrect term; However, it is commonly used. The drugs do not change the thickness of the blood, just inhibits the clotting cascade
Thrombolytics used to dissolve such life- threatening clots. Hemostatics used to speed clot formation, or to limit bleeding from a surgical site.
Anticoagulants prevent the formation and enlargement of clots.
Actions › Inhibit certain clotting factors › Lengthen clotting time › Prevent thrombi from forming or growing larger Adverse effect is bleeding. › Specific blockers administered to reverse the anticoagulant effects
heparin (Hep-Lock warfarin (Coumadin) Coumadin therapy can overlap heparin therapy Do not give ASA with these drugs RANDI Precautions
Antidotes: › Protamine sulfate is used for heparin › Vitamin K is administered for warfarin.
Foods high in Vitamin K can reverse the action of warfarin (Coumadin) Green leafy vegetables Milk and milk products Some cereals Orange juice Cauliflower Cucumbers
Prothrombin time (PT) › Normal range for PT is 12 to 15 seconds › Prolonged with anticoagulant treatment. International Normalized Ratio (INR) Method of performing PT tests varies from laboratory to laboratory
This is PT multiplied by a correction factor. Recommended post-treatment INR values range from 2 to 4.5.
Most common and potentially serious adverse effect is bleeding. Signs: › Bruising › Bleeding gums › Nosebleed › Blood in urine or stool
Antiplatelet agents prolong bleeding time by interfering with platelet aggregation.
Used to prevent clot formation in arteries. Three primary subclasses of antiplatelet agents › Aspirin › Adenosine diphosphate (ADP) receptor blockers › Glycoprotein IIb/IIIa receptor blockers.
Thrombolytics are used to dissolve existing clots.
Prescribed for disorders in which a clot has already formed, including the following: › Acute MI › Pulmonary embolism › Cerebrovascular accident (CVA) › DVT
Prescribed for disorders in which a clot has already formed, including the following: › Arterial thrombosis › Coronary thrombosis › To clear thrombi in arteriovenous cannulas and blocked IV catheters
Hemostatics are used to promote the formation of clots.