Pharmacology ch. 48 Drugs Affecting Blood Coagulation
Thromboembolic disorders
Involve formation of thrombi resulting in decreased blood flow or total occlusion of a blood vessel -Hypoxia, anoxia, necrosis
Hemophilia
Genetic lack of clotting factors that leaves the patient vulnerable to excessive bleeding with any injury.
MOA of Hemostatic Agents aminocaproic acid (Amicar)
Inhibits plasminogen activator substances and has antiplasmin activity that inhibits fibrinolysis and prevents the breakdown of clots
Anticoagulants
Interfere with the clotting cascade and thrombin formation by preventing or lessening a blood clot -NOT a thinner!!!!! Does not thin blood, it stops potential for a blockage.
What lab value should be monitored for a patient on warfarin? Partial thromboplastin time (PTT) Lactate International normalized ratio (INR) Complete blood count (CBC)
International normalized ratio (INR)
What should be avoided when a patient is on warfarin? Electric razors Intramuscular (IM) injections Pressure dressings Deep breathing exercises
Intramuscular (IM) injections
How does warfarin work? It suppresses vitamin K and "thins" the blood. It dissolves already formed clots. It prevents platelets from sticking to coronary arteries. It decreases the pressure in the vessels.
It suppresses vitamin K and "thins" the blood. -vitamin K is used to reverse the effects of warfarin
Be aware of ___ before administering Antihemophilic factor drugs.
Liver disease
Antiplatelets
Alter the formation of the platelet plug
A patient is ordered subcutaneous heparin every 8 hours. When the patient asks what this medication is for, what is the nurse's best answer? "It is to prevent you from developing a blood clot." "It will keep your current clots from getting bigger." "Everyone is on this medication." "It allows us to trend your aPTT levels."
"It is to prevent you from developing a blood clot."
Drug-drug for antiplatelet drugs (Aspirin)
Another drug that affects blood clotting
What classification of medications does warfarin fall under? Antiplatelet Anticoagulant Thrombolytic Antihypertensive
Anticoagulant
What type of medication is heparin? Antiplatelet Anticoagulant Thrombolytic Antihypertensive
Anticoagulant
Patients with classic hemophilia, also known as hemophilia A, need to be given replacement of which to treat bleeding episodes or when having surgery? Factor VII Factor VIII Factor X Factor XIII
Factor VIII
Enoxaparin (Lovenox) is prescribed when...
for the prevention of deep vein thrombosis (DVT) that may lead to pulmonary embolism (PE) after hip replacement or abdominal surgery; prevention of ischemic complications of unstable angina or non-Q-wave MI; and prevention of DVT in clients with severely restricted mobility due illness.
Vitamin K rich foods include
leafy greens, green tea, chard, soybean, kale, spinach
Indication of Hemostatic Agents aminocaproic acid (Amicar)
prevent systemic clot breakdown to prevent excessive blood loss -used in war(on battlefield), ER (surgery when a massive bleed is present) acute serious situations
Thrombolysis
process of dissolving or breaking down blood clots
Hemostasis is created by
protective mechanisms to prevent excess blood loss -Vascular constriction -Formation of the platelet plug= decreased blood flow -Activation of coagulation cascade -Formation of a blood clot to stop blood loss
fibrin
protein that forms the basis of a blood clot
Back in the day, Aspririn came from...
the bark of a willow tree
Coagulation
12 or more step process of blood clotting
Liver Disease
Clotting factors and proteins needed for clotting are not produced.
A patient is on a heparin infusion. Which lab value is used to titrate this medication? International normalized ratio (INR) Prothrombin time (PT) Activated partial thromboplastin clotting time (aPTT) Hemoglobin
Activated partial thromboplastin clotting time (aPTT)
Contraindications of thrombolytic drugs Alteplase (Activase)
Any condition that would be worsened by dissolution of clots
A patient is able to walk only short distances due to intermittent claudication. Which does the nurse expect the provider to prescribe? Cilostazol (generic) Clopidogrel (Plavix) Prasugrel (Effient) Ticlopidine (generic)
Cilostazol (generic)
Which medication is an example of an antiplatelet? Atropine Clopidogrel Warfarin Alteplase
Clopidogrel
The low molecular weight heparin of choice for preventing DVT after hip replacement therapy is A. heparin. B. betrixaban. C. fondaparinux. D. enoxaparin.
D. enoxaparin.
Indications of Anticoagulants (Heparin + Enoxaparin (Lovenox)+ Warfarin (Coumadin))
DVT, Pulmonary embolism (PE), treatment of AF
Indications of thrombolytic drugs Alteplase (Activase)
Dissolution of formed thrombus (e.g., formed during acute MI, PE, or ischemic stroke)
Adverse effects of Hemostatic Agents aminocaproic acid (Amicar)
Excessive clotting CNS, GI, weakness, fatigue, malaise, and muscle pain most serious- DIC (Disseminated intravascular coagulation) when blood clots form rapidly throughout the body= death "Greys Anatomy"
Drug-drug interactions of Hemostatic Agents aminocaproic acid (Amicar)
Heparin, oral contraceptives or estrogen
MOA of antiplatelet drugs (Aspirin)
Inhibit platelet adhesion and aggregation by blocking (prostaglandin) receptors sites on the platelet membrane. -Anagrelide - Blocks the production of platelets in the bone marrow -blocks or lowers number of platelets
MOA of Anticoagulants (Heparin + Enoxaparin (Lovenox)+ Warfarin (Coumadin))
Inhibits (new) thrombus and clot production by blocking the conversion of prothrombin to thrombin and fibrinogen to fibrin
Which intervention should be implemented for patients on any medications that increase the risk of bleeding? Utilize basic razors. Encourage intramuscular (IM) injections. Monitor for dark stools. Disregard fall precautions.
Monitor for dark stools.
How should intravenous (IV) heparin be administered? By gravity, counting drips By an advanced practice RN On a pump with guardrails On a pressure bag
On a pump with guardrails
Drug-drug interactions of Anticoagulants (Heparin + Enoxaparin (Lovenox)+ Warfarin (Coumadin))
Other drugs or substances that increase bleeding risk Warfarin: vast number of drugs Other interactions specific to each agent; check before use
Bone Marrow Disorders
Platelets are not formed in sufficient quantity to be effective.
Which factor is an absolute contraindication to receiving a thrombolytic? Ischemic stroke Pregnancy Appendectomy 2 years ago Controlled hypertension
Pregnancy
What is the antidote for heparin? Vitamin K Protease inhibitors Vitamin D Protamine sulfate
Protamine sulfate
A patient is on a heparin infusion. How does the nurse know if the medication is infusing at a therapeutic rate? The international normalized ratio (INR) is between 2 and 3. The prothrombin time (PT) is 1.5 to 2 times the normal time. The activated partial thromboplastin clotting time (aPTT) is 1.5 to 2.5 times the normal time. The potassium level is between 3.5 and 5.
The activated partial thromboplastin clotting time (aPTT) is 1.5 to 2.5 times the normal time.
How do anticoagulants work? Thin the blood to prevent clots and stop clots from getting bigger. Prevent platelets from sticking to stents. Dissolve clots. Decrease bleeding times.
Thin the blood to prevent clots and stop clots from getting bigger.
Dysfunction of hemostasis includes...
Thrombosis and Bleeding
Plasmin
an enzyme that dissolves/breaks down fibrin of blood clots -lyses thrombi
Antiplatelet agents are more effective against ______thrombosis; anticoagulants are more effective against _____ thrombosis.
arterial; venous
Too much Fibrinogen cause
blood clots to form in the bloodstream = bad -decreased circulation, leading to MI, arrhythmia, hypovolemia, stroke
when the body has the ability to produce plasminogen, it can
dissolve/ breakdown clots
A low-weight heparin that gives less of a heparin induced allergy reaction is known as...
enoxaparin (lovanox)
Adverse effects of Antihemophilic factor drugs
-involve risks associated with the use of blood products -Headache, flushing, fever, chills, lethargy -Nausea and vomiting -Stinging, itching, and burning at the site of injection
Which is a topical hemostatic agent that is applied directly to an injured area to promote clotting? Aminocaproic acid (Amicar) Coagulation factor VIIa (NovoSeven) Factor IX complex (BeneFix) Microfibrillar collagen (Avitene)
Microfibrillar collagen (Avitene)
Remind pt that you must match blood types and infection can occur. How will you say it?
Although blood work/tests go through a thorough process, filters do not clean out every cell, so infection may be possible.
Hemorrhagic disorders
-Excess bleeding -Less common than thromboembolic disorders
Indications for antiplatelet drugs (Aspirin)
-Treat CV diseases prone to producing occluded vessels. -Maintenance of venous and arterial grafts. -Prevent cerebrovascular occlusion. -Treat peripheral artery disease. -Adjuncts to thrombolytic therapy in the treatment of MI; prevention of reinfarction after MI.
How long does it take for warfarin to take effect? Immediately 8 to 12 hours 1 to 2 days 3 to 4 days
3 to 4 days
Adverse effects of Anticoagulants (Heparin + Enoxaparin (Lovenox)+ Warfarin (Coumadin))
Bleeding Heparin: heparin-induced thrombocytopenia
When taking warfarin, you must look at INR and PT. Which levels are for what?
pt- normal is 21-35 sec goal is 1.5-2.5x normal INR- 1, goal is 2-3 1.5-2.5- prophylaxis 2.5-3.5 -history of MI, DVT, CVA 3.5-4.5 - valve/artery arrhythmia, stent
Adverse effects for antiplatelet drugs (Aspirin)
-Bleeding in urinary or GI tract- hold med if an ulcer is present too. -Headache, dizziness, and weakness -GI distress -toxicity
Indications of Antihemophilic factor drugs
-Prevent blood loss from injury or during surgery. -Treat bleeding disorders. -Drug of choice depends on particular hemophilia being treated or particular coagulation abnormalities.
When anticoagulant therapy (warfarin) is used, the international normalized ratio is maintained between...
2 and 3.
What is the goal of APTT for a pt taking heparin?
60-100 Antidote- protamine sulfate
MOA of thrombolytic drugs Alteplase (Activase)
Acts as an enzyme that Work to activate natural anticlotting system Activate tissue plasminogen Effective only if patient has plasminogen in the plasma
A thrombolytic agent would be most indicated for which circumstance? A. CVA within the last 2 months B. Acute MI within the last 3 hours C. Recent, serious GI bleeding D. Obstetric delivery
B. Acute MI within the last 3 hours
Which is true of warfarin? A. Side effects include increased risk of clotting. B. Therapy may take multiple days of dosing to become therapeutic. C. It works by inhibiting activation of factor X. D. It is only administered IV.
B. Therapy may take multiple days of dosing to become therapeutic.
Warfarin, an oral anticoagulant, acts A. to directly prevent the conversion of prothrombin to thrombin. B. to decrease the production of vitamin K clotting factors in the liver. C. as a catalyst in the conversion of plasminogen to plasmin. D. immediately, so it is the drug of choice in emergency situations.
B. to decrease the production of vitamin K clotting factors in the liver.
Adverse effects of thrombolytic drugs Alteplase (Activase)
Bleeding Cardiac arrhythmias Hypotension Hypersensitivity - Rash, flushing, bronchospasm, and anaphylactic reaction
Thrombolytic Drugs
Break down the thrombus that has been formed by stimulating the plasmin system -work at the site of which platelets stick together -pt must get a CT before administration and symptoms must appear 6 hours before
Heparin reacts to prevent the conversion of prothrombin to thrombin. Heparin A. is available in oral and parenteral forms. B. takes about 72 hours to have a therapeutic effect. C. has its effects reversed with the administration of protamine sulfate. D. has its effects reversed with the injection of vitamin K.
C. has its effects reversed with the administration of protamine sulfate.
Blood coagulation is a complex reaction that involves... A. vasoconstriction, platelet aggregation, and plasminogen action. B. vasodilation, platelet aggregation, and activation of the clotting cascade. C. vasoconstriction, platelet aggregation, and conversion of prothrombin to thrombin. D. vasodilation, platelet inhibition, and action of the intrinsic and extrinsic clotting cascades.
C. vasoconstriction, platelet aggregation, and conversion of prothrombin to thrombin.
MOA of Antihemophilic factor drugs
Replace clotting factors that are either genetically missing or low in a particular type of hemophilia.
Effective dose-dependent prevention of platelet aggregation can be seen within 2 hours of a single oral dose of ______, but the onset of action is _____, so a loading dose of 300 to 600 mg is usually administered.
clopidogrel (aspirin); slow
