Anticoagulants Flashcards
1
Q
What is the most common use of anti-coagulant meds?
A
Treat & prophylaxis of venous thromembolism (VTE)
2
Q
What is the purpose of prophylaxis anti-coagulant therapy?
A
B/c the last thing we want is an actual clot to form & break off & travel to lungs or brain
3
Q
Prophylaxis of VTE with anti-coagulants is to prevent what 2 things?
A
1) Pulmonary embolism (PE)
2) Deep venous thrombosis (DVT)
4
Q
List 4 other indications for using anti-coagulant meds
A
1) Acute coronary syndromes (ACS)
2) Atrial fibrillation
3) Prosthetic heart valves
4) Post-surgical use
5
Q
What is the goal of anti-coagulant therapy?
A
Prevent formation of a clot & progression of an already formed clot
6
Q
List the 2 pathways involved in the coagulation cascade
A
1) Intrinsic
2) Extrinsic
7
Q
What is intrinsic pathway monitored by?
A
aPTT
8
Q
What is the extrinsic pathway monitored by?
A
PT/INR
9
Q
Which pathway comes into play when talking about warfarin & heparin?
A
The extrinsic pathway
10
Q
Where does the common pathway occur?
A
At factor Xa where both the intrinsic and extrinsic pathways converge
11
Q
List the conversion of proteins that occurs during the coagulation cascade after common pathway begins
A
Prothrombin → thrombin → fibrinogen → fibrin → stable fibrin clot
12
Q
Primary homeostasis:
If a vascular injury occurs what is the inflammatory response? Hint: 5
A
1) Vasoconstriction
2) Platelet activation (vWF; Fibrinogen bind)
3) Create the platelet plug
4) Leads to blood clot
5) Plasmin causes fibrinolysis & clot degradation
13
Q
Secondary homeostasis:
If a vascular injury occurs how does the coagulation cascade come into play? Hint: 5
A
1) Platelets activate coag cascade
2) Cascade activates conversion of thrombin to fibrinogen
3) Fibrinogen converts to fibrin
4) fibrin forms the blood clot
5) Plasmin causes fibrinolysis & clot degradation
14
Q
Where can we find a lot of clotting factors inside the human body?
A
The liver → want them activated as well!!
15
Q
Is fibrinogen soluble or insoluble?
A
Soluble
16
Q
Is fibrin soluble or insoluble?
A
Insoluble
17
Q
What does a damaged or injured blood vessel trigger?
A
Release of clotting factors
18
Q
Once clotting factors are released what is formed?
A
Platelet plug
Vasoconstriction limits BF & plts form a sticky plug
19
Q
After the platelet plug is formed what happens?
A
Development of a clot
Fibrin strands adhere to the plug to form an insoluble clot (helps protect us)
20
Q
List 3 common coagulation tests
A
1) Prothrombin time (PT)
2) International normalized ratio (INR)
3) Activated partial thromboplastin time (aPTT)
21
Q
Prothrombin time (PT) Hint: 3
A
1) Measures time it takes for plasma to clot
2) Extrinsic pathway
3) Ref range: 10-13 sec
22
Q
International normalized ratio (INR) Hint: 2
A
1) Standardizes the reporting of PT values
2) Reported for patients receiving Warfarin (Coumadin)
23
Q
What two coagulation tests must always be ordered together?
A
PT/INR
24
Q
Activated partial thromboplastin time (aPTT) Hint: 3
A
1) Measures time it takes for plasma (blood) to clot when exposed to a reagent
2) Intrinsic pathway
3) Ref range: 30-45 sec
25
Platelet functions:
What is the first step in maintaining homeostasis?
Platelet adhesion
26
What 2 things occur along with platelet adhesion?
1) Vasoconstriction
2) Formation of platelet plug
27
List 2 things platelets activate
1) Arachidonic pathway
2) Coagulation cascade
28
What is platelet aggregation induced by?
The release of Thromboxane A
29
List 2 functions of platelet aggregation
1) Stabilizes platelet plug
2) Activates Clotting cascade
30
Clot retraction and clot dissolution is regulated by...
Thrombin plasminogen activators
31
List the 3 classes of anti-coagulant medications
1) Anti-platelets
2) Anti-coagulants
3) Thrombolytic agents
32
Anti-platelet drugs
**Small guns → very potent**
Decrease aggregation & formation of platelet clot
33
Anti-coagulants
**Medium guns → more potent than anti-plts**
Interfere with clotting cascade & thrombin formation
34
Thrombolytic agents
**Big guns**
Break down the thrombus (clot) by stimulating plasmin
35
Anti-platelets:
When there is injury to the vessel what do the plts do?
Aggregate to the site of injury
36
Anti-platelets:
Once plts are at the site they release...
ADP & serotonin which help bring plts together
37
Anti-platelets:
ADP is a precursor to ____
Prostaglandins
38
What else is produced when injury occurs and what does it increase?
Thromboxane A → increases vasoconstriction & plt aggregation
39
What is the job of anti-platelets?
Inhibit plt adhesion & aggregation by blocking COX-1
40
What is average lifespan of platelets?
7-10 days
41
What 3 baseline lab values do we need to know before giving anti-platelets?
1) Hgb
2) Hct
3) Platelets
42
What plt value would require a call to the doctor before giving the med?
< 150,000 / µL
43
Acetylsalicyclic acid (ASA) is used to prevent
Platelet aggregation
**Anti-platelet**
44
List 5 indications for giving ASA
1) CAD/ CVA/ PAD prevention
2) Maintains AV grafts
3) Post MI
4) Post stent placement
5) Other vascular diseases
45
What does ASA inhibit?
Prostaglandin production
46
What does ASA bind to?
Highly bound to plasma proteins
47
How long does ASA inhibit plt aggregation for?
A single dose (325 mg) can inhibit plt aggregation for the life of the plt (7-10 days)
48
How long prior to surgery should ASA be stopped?
At least 1 week prior
49
What is important to keep in mind if ASA is being used for pain relief?
It could cause some bleeding as it is still an anti-platelet
50
Who should take baby ASA (81 mg; low dose)?
Patients who have had heart attacks are usually on low dose
51
List 2 side effects of ASA
1) Bleeding
2) GI side effects
52
What type of ASA can help decrease GI side effects?
Baby ASA → enteric-coated
53
What types of patients should ASA be used cautiously in?
Those w/ hepatic/ renal impairment
54
List 3 things caused by ASA toxicity
1) **Tinnitus**
2) Hyperventilation
3) Metabolic acidosis
55
What age group should NOT receive ASA?
Children < 18 yrs → can cause Reye syndrome
56
What is Reye syndrome?
Rare but serious condition that can lead to brain as well as liver damage (in some cases can be lethal)
57
Drug interactions of ASA:
List 5 drugs that can increase risk of toxicity if taken with ASA
1) Oral anti-coagulants
2) Heparin
3) Methotrexate
4) Oral DM meds
5) Insulin
58
Drug interactions of ASA:
What kind of meds may decrease ASA effects & cause ulcers?
Steroids
59
List 3 other drug interactions of ASA
1) ACE inhibitors
2) Beta blockers
3) NSAIDs
60
Why are NSAIDs contraindicated if taking ASA?
Counteract & compete with COX-1 site that we want on the plts
61
Patient teaching for ASA:
How to prevent bleeding **Hint: 2**
1) Soft bristle toothbrush
2) Electric razor (both males & females)
62
Patient teaching for ASA:
List 2 teaching points
1) Do NOT stop taking on own
2) Call MD for any signs of bleeding
→ Nosebleed > 5 min
→ Black tarry stools
→ Heavy menstrual cycle
→ Excessive bruising (that gets bigger)
63
Patient teaching for ASA:
Preventing risk of GI bleeding **Hint: 4**
1) Always take with food
2) Watch alcohol (ETOH) intake
3) Limit caffeine intake
4) Do NOT chew enteric-coated tabs
64
What could happen to a patient who is on ASA after a heart attack (MI) if they stop taking it?
Increases risk of another HA
65
What other anti-platelet is often used in combination with ASA?
Clopidogrel (plavix)
66
How does Clopidogrel (plavix) work?
Inhibits ADP receptors through P2Y12 inhibitors
→ Precursor to prostaglandins
→ Inhibits plt aggregation
67
List 2 indications for giving Clopidogrel (Plavix)
1) Post stent
2) Post MI
68
How long after taking Clopidogrel (plavix) will it start to take effect?
Starts to work in 24-48 hrs but not see full effects for 4-6 days
69
How should Clopidogrel (plavix) be taken?
With or without food
70
When should Clopidogrel be stopped prior to surgery?
4-10 days prior
71
Clopidogrel is generally well tolerated but may cause what 2 Sx?
1) Rash
2) Diarrhea
72
What lab test should we get prior to starting someone on Clopidogrel? & what levels should we monitor?
Get a CBC and monitor P2Y12 levels to see what's going on
73
List 4 other Anti-platelet drugs that are P2Y12 inhibitors
1) Ticagrelor (Brilinta)
2) Prasurgrel (Effient)
3) Ticlopidine (Ticlid)
4) Cangrelor (Kengreal)
74
List 2 pros and 1 con of the other P2Y12 inhibitor drugs (besides Plavix)
Pros:
1) May be more effective in ↓ plt aggregation than plavix
2) Quicker onset
Cons:
1) Now have generic, but still expensive
75
List 6 reasons P2Y12 inhibitors should not be given
1) Known bleeding disorders
2) Active bleeding
3) Closed head injuries
4) CVA until we can prove theres no bleed (hemorrhagic stroke = NO)
5) Pregnancy
6) Lactation
76
List 4 adverse effects of P2Y12 inhibitors
1) **Bleeding**
2) H/A
3) GI effects (N/V)
4) Skin rashes
77
What should patients look out for when on P2Y12 inhibitors to determine if they're bleeding? **Hint: 4**
1) Increased bruising
2) Bleeding gums
3) Shaving/ small cuts
4) Severe bleeding w trauma/ falls
78
Why is it important to know what herbal supplements a patient is taking if prescribed an anti-platelet?
Many herbal supplements can inhibit plt aggregation as well
79
List 3 things to remember for ALL anti-platelet drugs
1) Only prescribing doc can stop the med
2) Must take every day, unless instructed otherwise
3) Medication should be stopped min of 2-5 days (~ 1 wk) prior to surgery or elective procedure
80
List 2 functions of anti-coagulants
1) prevent new clots from forming
2) Prevent growth of existing clots (i.e. MI)
81
List 2 things anti-coagulants do NOT do that ppl believe they do
1) Thin blood
2) Dissolve a clot
82
List 2 indications for prescribing anti-coagulants
1) DVT
2) Clot from A-fib
83
List 3 conditions that increase coagulation activity
1) Stasis of blood flow
2) Increase production of pro-coagulation factors
3) Decrease in anticoagulant factors
84
Coagulation activity:
Stasis of BF **Hint: 3**
1) Immobility, sedentary or post-op pts
2) HF
3) A-fib
85
Coagulation activity:
Increase production of pro-coag factors **Hint: 3**
1) Cancer
2) Pregnancy & PP period
3) Oral contraceptives
86
Coagulation activity:
Decrease in anticoagulant factors **Hint: 2**
1) Cirrhosis (chronic liver failure)
2) Vit K deficiency
87
List 6 drugs considered anti-coagulants
1) Heparin
2) Warfarin (Coumadin)
3) Apixaban (Eliquis)
4) Dabigatran (Pradaxa)
5) Enoxaparin (Lovenox)
6) Rivaroxaban (Xarelto)
88
How does heparin work?
**Anti-thrombin inhibitor**
→ interferes w/ conversion of prothrombin to thrombin
89
List 2 routes of admin for heparin
1) SubQ
2) IV
90
When would heparin be the drug of choice?
Acute patients due to its fast onset of action
91
List the 2 types of heparin
1) Unfractionated
2) Low molecular weight heparin (LMWH)
92
What is the antidote for heparin?
Protamine Sulfate
93
When would you use the antidote: Protamine Sulfate?
If a person's platelets are really being impacted by anticoagulant properties of heparin
94
List 2 examples of patients coming into the hospital who should NOT receive heparin
1) Patient w an open fracture
2) Hypotension secondary to bleeding
95
How is heparin initially administered?
As an IV bolus or loading dose, followed by continuous drip
96
How many units of heparin is usually given in a bolus?
5000 Units
97
What is the usual heparin drip rate?
1000-1300 Units/ hr
98
How many units of heparin are given if basing off weight?
80 Units/ kg (can be less) as bolus & then 18 units/ kg/ hr
99
List 1 thing to monitor when giving a heparin drip
1) aPTT usually 1.5-2.5 times baseline control
→ Nomogram/ protocol usually used
→ PTT should normalize ~ 2-6 hrs after heparin stops
100
When should PTT be checked after starting heparin?
6 hrs later → then determine if dose should ↑, ↓, or stay the same
101
What would happen to the patient if their PTT is too high?
They will bleed
102
What would happen to the patient if their PTT is too low?
Clots will grow
103
What must ALWAYS be checked when giving heparin?
Dose with another RN → b/c it's a high risk drug
104
Calculating a heparin drip:
Patient: weight 185 lbs. (84 kg). Heparin 25,000U/250 ml D5W. Order reads: Heparin 1350 units/hour. aPTT comes back at 80 seconds .
Following the protocol, what adjustments are indicated?
**Units per hour to decrease drip ________
**New units per hour_______
**ml/hr_______
1) Decrease infusion rate by 2 units/kg/hr → 2 x 84 kg = 1680U
2) New units per hr = 1184 U/hr → 1350 - 168 = 1184
3) mL/hr = 11.84 → 250 mL/ 25000U x 1184U / 1 hr
105
How does unfractionated heparin work?
Inhibits thrombus & clot formation by blocking factor Xa
106
What are the 2 routes unfractionated heparin can be administered?
1) IV
2)SubQ
107
List 2 things to note ab unfractionated heparin
1) Should not be mixed (multiple drug interactions)
2) Safe in pregnancy, but considered 2nd line therapy
108
List 3 adverse effects of unfractionated heparin
1) Bleeding
2) Heparin-induced thrombocytopenia
3) Hypersensitivity
109
Therapeutic range for unfractionated heparin
Narrow therapeutic range
**Requires lab monitoring**
110
What should PTT be if pt is on unfractionated heparin?
In therapeutic range = 46-70
**Call physician if > 70**
111
What is low molecular weight heparin (LMWH) used for?
Commonly used for DVT prophylaxis, MIs
**Drug of choice if they do NOT have clot already**
112
List 2 drugs considered LMWH
1) Enoxaparin (Lovenox)
2) Dalteparin (Fragmin)
113
How should LMWH be administered?
**SubQ only**
→ Admin 2 in away from umbilicus; no rubbing/ no aspiration
114
Is LMWH safe during pregnancy?
YES → considered 1st line
115
Does LMWH require lab monitoring?
NO
116
What type of heparin could a pt be discharged home on?
LMWH
117
What is another reason to be extremely careful with heparin dosing?
There is a lot of dose variability (from 1,000 to 50,000 units) → could impact pts risk of bleeding
118
How does heparin-induced thrombocytopenia occur?
Caused by Ab directed against complexes formed by a plt protein, plt factor 4, & heparin
**Usually takes ~ 1-4 days after initial intro to heparin**
119
Heparin- induced thrombocytopenia important points **Hint: 2**
1) Potentially life-threatening immune complication
2) Plt count drops by half within 24 hrs of admin
120
List 5 management options for heparin-induced thrombocytopenia
1) Stop the heparin
2) Alternative anticoagulant, if needed
3) Antidote: Argatroban → direct thrombin inhibitor
4) Lepirudin (Refluden → another antidote not as used)
5) Monitor for bleeding
