Chapter 32 & 10 (Learning Outcomes) Flashcards
Define anticoagulant
Prevent new thrombus formation and the extension of existing thrombi
- keep blood from clotting
- exist naturally
Define anticoagulant
Prevent thrombus formation and the extension of existing thrombi
- keep blood from clotting
- exist naturally
What are two types of anticoagulants?
- Heparin (parenteral)
2. Warfarin (oral)
What is the action of thrombolytics (how is it different than anticoagulants)?
Dissolves EXISTING clots
What is the action of antiplatelet therapy?
Decreases the ability of platelets to stick together
What are the areas of the body that produces heparin naturally?
- Lungs
- Liver
What drug is used to prevent the extension of a blood clot, particularly in patients with DVT or PE?
Heparin
What is the route of administration for Heparin?
Parenterally
IV: onset immediate
SC: onset 20-60 minutes
Describe the pharmacodynamics of heparin
Heparin (along with antithrombin) rapidly promotes the inactivation of factor X
- prevents the conversion of prothrombin to thrombin
True or False:
Heparin has no effect on blood clots that have already been formed
True
When is Heparin contraindicated?
- Thrombocytopenia
- Bleeding disorders
- Active bleeding (other than DIC)
What is the most common adverse effect of heparin?
Bleeding
What is administered if a patient receives an overdose of heparin?
Protamine sulfate
- a strong base that reacts with heparin (a strong acid) to forma a stable salt, thereby neutralizing the anticoagulant effects of heparin
What core patient variables should be assessed prior to giving heparin?
- pre-existing prolonged bleeding time
- aPTT
- platelet count
- renal function
- hematocrit
What core patient variables should be assessed prior to giving heparin?
- pre-existing prolonged bleeding time
- aPTT
- platelet count
- renal function
How do you determine the therapeutic range for heparin?
Multiply the control by 1.5 and then by 2
- therapeutic range is between these two numbers
(Ex: Control time = 30 seconds. Therapeutic range = 45 - 60 seconds)
To minimize the risk of heparin-induced thrombocytopenia (HIT), when does the platelet count have to be monitored?
Every day for 14 days
- or until heparin is discontinued
- whichever comes first
How long should a patient be given heparin for to reduce the risk of developing a DVT or PE?
Low risk = 3 months
High risk = 6 months to indefinitely
- initially treatment begins with heparin for 5 days, but then continues with oral anticoagulant afterwards
What is the patient education for heparin?
Report any blood in: - urine - stools Bleeding from: - gums - nose - vagina - wounds
What are the important education points for patients administering Enoxaparin themselves?
- locating appropriate injection site and rotating injection sites
- performing SC injections using appropriate technique
- disposing of syringes and needles appropriately
- PATIENTS may RECAP their own needle
What are the important education points for patients administering Enoxaparin themselves?
- reason for therapy
- taking it on time
- having follow-up blood analyses done as recommended
What are the names of the drugs that are in the class of direct thrombin inhibitors (3)?
- Argatroban
- Bivalirudin
- Lepirudin
How are direct thrombin inhibitors different than heparin?
Bind to active thrombin site and inhibit both free and clot-bound thrombin
What is the prototype drug for oral anticoagulants?
Warfarin (Coumadin)
What is measured to determine therapeutic levels of warfarin?
INR
- international normalized ratio
- compares patient prothrombin time to standard prothrombin time
For treatment or prophylaxis of a thrombus or embolus, what should the INR be equal to?
2 - 3
- patient’s prothrombin time should be 1.4 - 1.6 times the control time
Describe the pharmacodynamics of warfarin
Works by competitively blocking vitamin K at its sites of action
- thus it prevents the activation of factors II, VII, IX, and X
- has not effect on factors that have already been activated
True or False:
Full therapeutic response of warfarin cannot be measured until 3 days after therapy begins
True
When is warfarin contraindicated?
- active bleeding
- open wounds
- ulcerations of the GI tract
- hemophilia
- thrombocytopenia
What is most frequent adverse effect of warfarin?
- Bleeding
- Hemorrhage
- N/V
- diarrhea
When can heparin be discontinued when warfarin has been started?
Once INR is between 2-3 for 2 days in a row
Why is it safe to use heparin and warfarin at the same time?
They affect different clotting factors
What is the antidote for warfarin?
High levels of vitamin K
- competes with warfarin for binding sites
What is another example (other than warfarin) that is an oral anticoagulant?
Anisindione (Miradon)
What is the function of antiplatelet drugs?
Prevent platelet aggregation
- prolongs bleeding time
What class of drugs does Clopidogrel fall into and what does it do?
Antiplatelet
- reduces the occurence of atherosclerotic events (MI, stroke, vascular death)
What are the adverse effects of using Clopidogrel?
- GI distress
- Abdominal pain
- Indigestion
- Diarrhea
- Nausea
What test should be performed prior to administering Clopidogrel?
Complete baseline blood count with differential
- to determine platelet functioning
What drug class is Aspirin close to?
Antiplatelet
- used prophylactically against thromboembolic complications (MI and TIA)
What is the function of hemorhelogic drugs?
Act on RBCs to reduce blood viscosity and increase the flexibility of RBCs
What is the function of thrombolytic drugs?
Assist in breaking down FORMED blood clots
What is the prototype drug for thrombolytic drugs?
Alteplase, recombinant (Activase)
Since Alteplase, recombinant has the potential for serious side effects, what is the recommended use limited to?
CONFIRMED PE or DVT
Describe the pharmacodynamics of Alteplase recombinant
It is an enzyme that, when fibrin is present, converts pasminogen to plasmin
- binds to the fibrin in a clot and converts the trapped plasminogen to plasmin
- fibrinolysis (breakdown of the clot) then occurs
What is the most frequent adverse effect of Alteplase, recombinant?
BLEEDING!
- internal (GI, GU, respiratory tracts or retroperitoneal, or intracranial areas)
- surface or superficial bleeding (punctures, incision sites)
What are the two drug classes used to treat hypocoagulation?
- Clotting factors
2. Hemostatic agents
If a patient is deficient in blood clotting factors, what is that associated with?
Prolonged bleeding and clot formation time
What is the prototype for clotting factor?
Antihemophilic factor (AHF)
What is anti-hemophilic factor (AHF) used for?
Is the effect long term or short term?
To prevent and control excessive bleeding
- effect is short term because the factor is used up in the clotting process
What is the administration route for anti-hemophilic factor?
Intravenously
- rapidly removed from plasma because it is used in the clotting process
True or False:
Antihemophilic Factor temporarily meets the needs for clotting factor to prevent or stop bleeding
True
What is the function of hemostatic drugs?
Stop blood loss by enhancing blood coagulation
What are the two types of hemostatic drugs?
- Systemic
2 Topical
What is the prototype systemic hemostatic drug?
Aminocaproic acid (Amicar)
Describe the pharmacodymanics of Aminocaproic acid (Amicar)
Prevents fibrinolysis in two ways:
- Blocks the action of plasminogen activators (thus interfering with the formation of active plasmin
- Interferes with the binding of active plasma to fibrin (thus preventing the breakdown of fibrin
What is the end result of Aminocaproic acid (Amicar)
Stabilization of a blood clot and control of bleeding
True or False:
Anticoagulants break down existing clots and prevent clots from forming
False
- Anticoagulants DO NOT break down existing clots but DO help prevent clots from forming
True of False:
Antiplatelet drugs prevent platelet aggregation and thereby prevent thrombus formation
True
True or False:
Hemorheologic agents break down existing clots
False
- Hemorheologic agents promote the flexibility of the RBCs and decrease blood viscosity to prevent thrombus formation
True or Flase:
Thrombolytic drugs break down existing clots
True
True or False:
In general, disorders of hypercoagulability result from either an increase in platelets or an increase in the activity of the clotting system (or both)
True
What is the benefit of a well-balanced diet?
May prevent chronic illness and therefore indirectly decrease the need for drug therapy
True or False:
If a patient has low dietary proteins levels, this could increase the concentration of FREE (unbound) drug in their system
True
- Diminished protein status results in lower amounts of plasma proteins and can substantially increase the concentration of free drug available
What is the most important blood protein that is involved in drug binding/action?
Albumin
True or False:
Distribution of fat-soluable drugs is decreased in obese and the elderly because of the decreased proportion of adipose tissue to lean body mass
FALSE
- Distribution of fat-soluable drugs is INCREASED in obese and the elderly because of the INCREASED proportion of adipose tissue to lean body mass
What is there a risk of when a patient is obese or elderly, and are taking fat-soluable drugs
Risk for an increase in adverse effects
Most protein binding by drugs occurs with which blood protein?
Albumin
What food affects the first-pass drug metabolism of many drugs?
Grapefruit
What can happen if you eat grapefruit while taking certain medications?
Can increase the bioavailability and corresponding increases in serum drug levels
(not affected as much by first-pass effect, therefore, more active drug is available)
What are some examples of foods that induce chemical oxidation when added to the diet and increase drug metabolism?
Cruciferous vegetables
- broccoli
- brussels
- sprouts
- cabbage
- cauliflower
- rutabaga
- turnips
What happens if you induce/increase drug metabolism?
Results in a LOWER serum concentration of the drug
What vitamin is important in the clotting process?
Vitamin K
State the core patient variables that can influence drug-nutrient interactions
- Abnormal dietary intake
- Use of herbs and nutritional supplements