PHARM WEEK 4 CARDIO AGENTS II Flashcards
The CNS which consists of the __ and __ __ are protected by the __, __, and __
brain & spinal cord
skull, spine, meninges
The Peripheral Nervous System (connects CNS to __ and __) are comprised of the __ __ system and __ __ system
Limbs and organs
Autonomic Nervous system
Somatic Nervous system
The Autonomic Nervous System is composed of:
1.
2.
- sympathetic nervous system (fight/flight)
2. parasympathetic nervous system (rest/digest)
the autonomic nervous system is also called the
visceral nervous system
Somatic nervous system =
voluntary control of body movements via skeletal musculature and with sensory reception of external stimuli, cranial, and spinal nerves
Sympathetic Nervous System (Adrenergic system) - prepares the body to cope with __ __
stress situations
SNS secretes :
epinephrine and norepinephrine
Epinephrine/Norepinephrine in the SNS has these effects on the body : (8)
- Increases HR
- Dilates the bronchioles
- Dilates the pupils
- Vasoconstricts blood vessels
- Vasodilates the skeletal muscles
- Slows peristalsis
- Relaxes uterus and bladder
- Converts glycogen to glucose by the liver
The parasympathetic nervous system secretes
acetylcholine
Acetylcholine from the PNS has these effects on the body: (7)
- Constricts pupils
- Contracts smooth muscle of the GI tract
- Constricts bronchioles
- Slows the heart rate
- Increases secretions/motility of the digestive tract
- contractions of bladder
- glycogen synthesis
What are the three types of angina pectoris?
- classic (or stable)
- unstable (pre-infarction)
- variant (Prinzmetal, vasospastic)
Classic (or stable) angina pectoris
reproducible symptom pattern; no change in pattern for 2 months or more
Unstable (pre-infarction) angina pectoris
occurs frequently over course of a day with increased severity due to coronary artery narrowing or partial occlusion
Variant angina pectoris
- occurs with rest, caused by vasospasm, rare
- some medications can stimulate vasospasms
What are the three types of antianginal drugs?
- nitrates
- beta-blockers
- calcium channel blockers
these antianginal drugs increase myocardial blood flow by: (2)
- increasing O2 supply (increasing oxygenated blood to the heart) OR
- decreasing O2 demand (decreasing workload)
Nitrates (6)
- Dilate peripheral blood vessels
- Decrease systemic vascular resistance (after load)
- decrease venous return to heart
- cause coronary artery dilation -> increase oxygen supply to the heart
- decrease left ventricular end diastolic pressure (pre-load)
- decreases preload -> decreases workload of heart and demand of oxygen from the heart
Beta-blockers: blockade of beta adrenergic receptors which leads to
- decrease in HR
- decrease in rhythm disturbance
- decreased incidence of angina
Beta-blockers can increase __ __, __ __ - this can be problematic for the asthma patient
airway resistance
bronchial constriction
Most common beta-blockers are:
metoprolol, atenolol
Blocking beta 1 receptors does what things?
- decreases HR
2. rhythm disturbances (prolongs action potential)
Selective beta blockers block with receptors?
beta 1 adrenergic receptors
Beta 1 =
heart
Beta 2 =
lungs (bronchial receptors)
Calcium activates __ __, increases the __ of the heart, and increases __ __
myocardial contraction
workload
oxygen demand
Calcium channel blockers inhibits __ from moving __ the heart and vessels. The smooth muscle contraction is reduced which causes__ __ which __ venous return to the heart (preload) and __ oxygen demand
Ca+
into
peripheral vasodilation
decreases
decreases
Calcium channel blockers decrease __ __ __
coronary artery spasm
Calcium channel blockers relax __ __ decreasing cardiac oxygen demand
peripheral arterioles
Common calcium channel blocker:
Amlodipine (Norvasc)
What are the 8 types of antihypertensive meds?
- Diuretics
- Beta (adrenergic) blockers
- centrally acting Alpha 2 Agonists
- Alpha (adrenergic) blockers
- Calcium channel blockers
- Angiotensin Converting Enzyme (ACE) inhibitors
- Angiotensin II Receptor Blockers (ARBs)
- Direct Renin Inhibitor
Diuretics promote __ and __ depletion which decreases __ __ __
Na+ ; water ;
extracellular fluid volume
Diuretics are effective as the __ __ __ for __ HTN
1st line treatment
mild
Loop Diuretics: give an example
Furosemide
Loop Diuretics: works __ and __
fast; effective
Loop Diuretic side effects:
- nausea
- diarrhea
- electrolyte imbalances (hypokalemia)
Loop diuretics are used in emergencies for __ and __ __
CHF, pulmonary edema
Thiazides: give an example
Hydrochlorothiazide (HCTZ)
Thiazides are associated with __ __
electrolyte imbalances
Thiazides compared to loop diuretics: (3)
- not as effective
- do not work as fast
- does not promote as much Na+ and water depletion
Thiazides inhibit active exchange of ___ in the cortical diluting segment of the __ __ __ __
Cl-Na
ascending loop of Henle
When thinking about Thiazides, only __ Na is going in urine b/c __ of Na has already been __ prior to the cortical diluting segment of the ascending loop of Henle
10%
90%
reabsorbed
K-sparing diuretics inhibit the reabsorption of __ in the __ __ and __ __
Na+
distal convoluted; collecting tubule
Loop diuretics inhibit exchange of _____ in the __ __ of the __ __ __ __
Cl-Na-K
thick segment
ascending loop of Henle
The category “Diuretics” does not include __ __
“secondary” diuretics - any drug whose primary target is not to diurese
The diuretics are the primary line of therapy for the majority of patients with __ __ and __ __. They decrease __ and __ which result from fluid retention
heart failure
pulmonary congestion
dyspnea, edema
Diuretic drugs are divided into what 3 categories?
- Thiazides
- Loop Diuretics
- Potassium-sparing
Where are aldosterone receptors found? (3)
- myocardium
- arterial walls
- kidneys
Aldosterone is a hormone that
promotes sodium/water retention and potassium/magnesium excretion
Aldosterone receptor antagonists block the action of aldosterone and inhibit the __-__ __ . Here, __ is retained and __ is excreted.
sodium-potassium pump
potassium ; sodium
Give an example of an aldosterone receptor antagonist:
spironolactone
Aldosterone increases the elimination of potassium and magnesium, creating an __ __ which may be responsible in part for __ __.
electrolyte imbalance
cardiac arrhythmias
At the tissue level, aldosterone stimulates the production of __, therefore being responsible for the __ that is found in hypertrophied myocardium and in the arterial walls of patients with heart failure
collagen
fibrosis
What three types of effects do aldosterone inhibitors exert?
- diuretic effect
- anti arrhythmic effect - mediated by the correction of hypokalemia and hypomagnesemia
- antifibrotic effect - can contribute to a decrease in the progression of structural changes in patients with HF
Beta- Adrenergic Blockers are also called what things?
- Sympatholytics
- Sympathetic depressants
- Beta (1,2) blockers
What do selective Beta1 blockers do? (4)
- decreases cardiac output
- decreases systemic vascular resistance
- lowers BP
- decreases HR, contractility and renin release
What is the prototype drug for beta blockers?
metoprolol (Lopressor)
What are adverse effects of beta blockers? (6)
- Hypotension
- Fluid retention - can worsen heart failure
- Fatigue
- Bradycardia - to the point of heart block
- In asthmatics (can worsen asthma)
- In Diabetics (masks hypoglycemic effects) - increased HR, beta blockers, decrease HR
Centrally acting alpha2 agonists: (4)
- These agonists ↓ sympathetic activity – causes a decrease in heart rate and blood pressure
- ↓ CO, serum epinephrine, norepinephrine, & renin release (causes vasodilation and decreased vascular resistance)
- Reduces peripheral vascular resistance and increases vasodilation
- Are never given with Beta Blockers because both could cause accentuation of bradycardia
Side effects/ Adverse reactions for Centrally Acting Alpha2 Agonists:
- drowsiness
- dry mouth
- dizziness
- bradycardia
- rebound hypertensive crisis if D/C abruptly
(if need to stop immediately, prescribe another antihypertensive) - Peripheral edema d/t Na+ and H2O retention
Give two examples of centrally acting alpha2 agonists:
- aldomet (older drug, given IV)
2. clonidine (PO and via patch, more common)
Alpha-adrenergic blockers causes
vasodilation and decreases BP
Alpha-adrenergic blockers do NOT affect __ __ or __ __
glucose metabolism or
respiratory function
Selective alpha1 adrenergic blockers are used to __ __ (and in BPH to relax the __ __ )
decrease BP
urethral constriction
Name the alpha-adrenergic blocker prototype:
Prazosin HCl (Minipress)
Alpha-adrenergic blockers: side effects/adverse reactions
- orthostatic hypotension
- nausea
- drowsiness
- edema
- weight gain
- impotence
What drug interaction occurs between alpha-adrenergic blockers and nitrates:
decreases BP
Alpha-adrenergic blockers are often given at __ to pas s the initial orthostatic hypotension
night
Angiotensin-converting enzymes (ACE) inhibitors inhibit the formation of __ __ which is a __ __
angiotensin II ; potent vasoconstrictor
ACE inhibitors block the release of __, which then causes __ excretion and __ retention
aldosterone
Na+
K+
ACE inhibitors cause (a major change/little change) in CO. Which one?
little change
ACE inhibitors lower the __ __ __
peripheral vascular resistance
What 3 other enzymes can be used to convert angiotensin I to angiotensin II BESIDES angiotensin-converting enzyme (ACE)?
- chymostatin-sensitive angiotensin-generating enzyme (CAGE)
- cathepsin G
- chymase
Is this true or false? Several nonrenin enzymes have been found that directly cleave angiotensin II from angiotensinogen without forming angiotensin I.
TRUE
The effects of angiotensin II are mediated through the __ __ divided into the __ and __ subclasses. The majority of deleterious effects of angiotensin II are provoked through the __ receptors. Angiotensin receptor blockers exert their effects through specific blockade of the __ receptors.
AT receptors
AT1 and AT2
AT1
AT1
What else do agents that block the RAAS accomplish besides lowering bp? (2)
- they slow the progression of renal disease in patients with DM
- beneficial in hypertensive patients with heart failure, recent myocardial infarction, and chronic kidney disease
common side effect of ACE inhibitors:
- nagging cough - angiotensin converting enzyme blocks bradykinin (more active bradykinin leads to nagging cough)
__ don’t have the nagging cough, but the effects of anti-hypetensive aren’t as effective as ACE inhibitors
ARBs
Do african-americans respond well to ACE inhibitors alone?
NO
Do elderly respond well to ACE inhibitors alone?
NO
ACE inhibitors are primarily used to treat
HTN
Some ACE inhibitors also treat
heart failure
ACE inhibitors should not be used in __
pregnancy
Can ACE inhibitors be taken with food?
yes, most can
what is the prototype drug for ACE inhibitors?
Captopril (Capoten)
__ is the most abundant intracellular cation
Under normal conditions, __ can adjust __ excretion
Potassium
kidneys; potassium
Hypokalemia - etiology (3)
- renal or nonrenal wasting
- decreased intake
- redistribution (e.g. insulin)
Hypokalemia increases the risk for
cardiac arrhythmias
Hypokalemia treatment
replacement either oral or IV (many instances given IV - however can be irritating, causing IV site to extravasate)
telemetry during severe hypokalemia
Hyperkalemia =
K+ > 5.0 mmol/ L
Hyperkalemia etiology (3)
- redistribution
- reduced K+ excretion
- Increased K+ intake
Pseudohyperkalemia
occurs with RBC hemolysis, leukocytosis (>70,000/mm^3) or thrombocytosis (>500,000mm^3)
Hyperkalemia Emergency
renal failure in setting of tumor lysis syndrome, rhabdomyolysis, tissue necrosis, large hematomas
What would you do if someone was in pseudohyperkalemia?
You would assume it was an emergency. You would get: 1. an EKG 2. look for peak T waves If those are there, you will treat assuming patient has hyperkalemia and redraw lab specimen
Hyperkalemia signs and symptoms (2)
- cardiac arrhythmias
2. lower extremity weakness
Hyperkalemia treatment
- Kayexalate - slow way to treat; drink, or thru enema
- Insulin - drives the K+ into the cells so we lower serum K+
- Calcium - stabilize heart to prevent heart dysrhythmias
- Renal dialysis
What is the 2nd most prevalent intracellular cation?
magnesium
Magnesium acts as a __ __ __
calcium channel antagonist
What are magnesium’s key roles? (2)
- muscle contraction
2. insulin release
What organ maintains magnesium balance?
kidneys
hypomagnesemia is present in __-_% of ICU patients
11-65%
Hypomagnesemia is due to __ or __ __
renal (increased tubular flow) or GI (diarrhea) losses
Hypomagnesemia can produce __ ___ –> __ __ __
cardiac arrhythmias
Torsade de Pointes
__ __ can occur when magnesium level
Neuromuscular irritability
_____ occurs in ~ __% of those with hypomagnesemia
hypokalemia; 40%
Treatment for hypomagnesemia (2)
- IV Magnesium Sulfate
- caution in patients with renal insufficiency (decreased doses) - Oral supplementation for long term replacement
Hypermagnesemia is __ and is usually due to __ __
rare
renal insufficiency
Typical setting of hypermagnesemia is treatment of __-__ __ or ____/____
pre-term labor
pre-eclampsia/eclampsia
What are symptoms of hypermagnesemia (5)
- loss of deep tendon reflex
- flaccid paralysis
- apnea
- bradycardia
- hypotension
Hypermagnesemia
treatment
- prevention
-do not give magnesium-containing antacids or cathartics
- stop infusion or
administering oral medications - Dialysis
- peritoneal or
hemodialysis
What are the two types of cardiovascular agents?
- Antidysrhythmics
2. Drugs for circulatory disorders
Cardiac action potential has __ phases
5
Cardiac Action Potential:
The movement of __ across the membrane allows for muscles to contract and relax
electrolytes
Phase 0 of Cardiac Action Potential:
Na enters cell -> this causes rapid depolarization -> sub sequential contraction
Phase 1 of Cardiac Action Potential:
Initial repolarization; Na stops entering the cell
Phase 2 of Cardiac Action Potential :
Plateaus, evens out
Ca++ enters, makes the contraction a little bit longer (calcium channel blockers block calcium making contraction shorter)
Phase 3 of Cardiac Action Potential:
Rapid repolarization, beginning of relaxation -> K+ exits the cell into the extracellular
Phase 4 of Cardiac Action Potential:
Resting membrane potential between heartbeats
what are the two types of dysrhythmia?
- atrial dysrhythmia
2. ventricular dysrhythmia
Atrial dysrhythmia:
- prevents proper filling of ventricles
- decrease CO by 1/3
- quivering of the atria doesn’t allow the heart to fully contract
Ventricular dysrhythmia:
- life threatening
- ineffective ventricular filling results in decreased or absent CO
- entire heart is quivering!
Examples of ventricular dysrhythmias:
- Premature Ventricular Complexes (PVC)
- Ventricular tachycardia
- Ventricular Fibrillation
- follow BCLS and ACLS
algorithm
- follow BCLS and ACLS
Dysrhythmias are also called
arrhythmias
Must give __ __ prior to and after surgery even if the patient is NPO (give with a sip of water)
__ causes side effects postoperatively
beta blockers
tachycardia
Causes of Dysrhythmia:
REMEMBER "TECH" T- Tension PTX Tamponade (cardiac) Toxins Thrombosis (pulmonary or coronary) Thyroid disease
E -
Excess catecholamines
Electrolyte imbalances
C-
Coronary artery disease
Cardiac Surgery
H- Heart attack Hypoxia Hypercapnia Hypovolemia Hydrogen ions (acidosis) Hypo-Hyperkalemia Hypothermia
Dysrhythmias are due to an influx of electrolytes affecting __ __
action potentials
Antidysrhythmics: Pharmacodynamics
- Block adrenergic stimulation of heart
- Depress myocardial excitability & contractility
- Decrease conduction velocity in cardiac tissue
- Increase myocardial recovery time (repolarization)
- Suppress automaticity (spontaneous depolarization to initiate beats)
Note: Most Antidysrhythmics are also proarrhytmic
antidysrhythmics prolong the __ __
refractory period
Antidysrhythmics: Class I
Fast (Sodium) Channel Blockers
- IA: procainamide (Pronestyl, Procan SR)
- IB: lidocaine (Xylocaine)
- IC: Propafenone (Rythmol), Flecainide (Tambocor)
Antidysrhythmics: Class II
Beta-Blockers:
Acebutolol (Sectral)
Esmolol (Brevibloc)
Sotalol (Betapace)
Antidysrhythmics: Class III
Drugs that Prolong Repolarization:
-Amiodarone (Cordarone)
Antidysrhythmics: Class IV
Slow (Calcium) Channel Blockers -
Verapamil (Calan, Isoptin) and Diltiazem (Cardizem)
Class 1A antidysrhythmic mechanism of action :
depress the phase 0 of the action potential leading to slow conduction, prolonged repolarization. Decreases automaticity and likelihood of ectopic foci, ↓ conduction velocity in cardiac tissues and increases refractory period. Slow conduction and prolonged repolarization
Class 1A uses:
Wide variety of ventricular & atrial dysrhythmias
Paroxysmal atrial tachycardia, supraventricular dysrhythmia
Examples of Class IA antidysrhythmics:
- Procainamide (Pronestyl)
- quinidine (Quinoglute)
- disopyramide (Norpace)
(these are drugs given for rapid heart rates)
Class 1A Procainamide absorption:
- oral extended release - 90 to 120 minutes
- IM - 15-60 minutes
Class 1A Procainamide metabolism and excretion:
- converted by liver to N-acetylprocainamide (NAPA), an active anti arrhythmic compound
- may vary among population
- 30-60% excreted unchanged by kidney
Class 1A Procainamide: Half life
Half-life - 2.5 to 4.7 hours (NAPA - 6 to 8 hours)
*prolonged in renal impairment
Procainamide: side effects
- Dose-related nausea
- anorexia
- vomiting
- dizziness
- drowsiness
- heart blocks
- hypotension
- CHF
Note: avoid citrus juices and fruits when taking quinidine
Procainamide: Side Effects during long-term therapy
- Lupus-like syndrome with rash and small joint pain
- Pericarditis with tamponade
- Notify prescribing provider immediately as may need to discontinue
Procainamide: Adverse Reactions
- Life threatening: caused by high concentrations (>19 micrograms/ml)
- hypotension
- marked slowing of conduction
- Torsade de pointes
What is Torsade de points?
Uncommon form of ventricular tachycardia (VT) characterized by changes in QRS complexes
It is associated with a prolonged QT interval. May evolve into V fib (cardiac arrest)
What else can procainamide be used for?
It can act as an anti-hypertensive.
It vasodilates the blood vessels (blocks phase 0)
PR interval
0.12-0.20 sec
QRS duration
0.08-0.10 sec
QT interval
0.4-0.43 sec
QT interval greater than __ seconds leads to higher risk of v-tach and v-fib
0.43
Drugs that can prolong QT interval (18)
- Amiodarone
- Erythromycin
- Ciprofloxacin
- Clarithromycin
- Cisapride
- Droperidol
- Famotidine (Pepcid)
- Fluconazole
- Haloperidol
- Lithium
- Methadone
- Octreotide
- Pentamidine
- Sotalol
- Tacrolimus
- Thioridazine
- Zofran (for vomiting)
- Fluoxetine (Prozac)
Procainamide: toxicity
What do you monitor?
What is the therapeutic level of procainamide & napa levels?
- Monitor serum procainamide & NAPA levels
- Therapeutic level:
Procainamide: 4-10 mcg/mL
NAPA: 15-25 mcg/mL
Combined levels: 10 – 30 mcg/mL
Toxicity may occur at procainamide
levels > 10 mcg/ml
which three signs signify a wide QRS and requires procainamide or amiodarone?
Vtach
Vfib
Torsade de pointes
Class II Antiarrhythmics prolongs which phase of the cardiac action potential?
Prolongs phase 4
Class II Antiarrhythmics mechanism of action:
blocks beta-adrenergic receptors, causing depression of phase 4 of the action potential. Slows the recovery of the cells, leading to slowing of conduction and automaticity. Can also reduce renin release (↓ BP)
Class II Antiarrhythmic uses
wide variety of ventricular and atrial dysrhythmias
- paroxysmal supraventricular tachycardia ( PSVT) and PVCs
Class II Antiarrhythmic examples
- Acetabutol (Sectral)
- emolol (Brevibloc)
see used in critical care
Class II Antidysrhythmics side effects, adverse reactions, and drug-drug interactions
1.Same as those of Class I and
III
2.Watch for bronchospasm and dyspnea
Class III Antidysrhythmics mechanism of action
Unclear mechanism. Blocks potassium and slows the upward movement of potassium during phase 3 of the action potential; prolongs the repolarization and slows the rate and conduction of the heart. Structurally similar to thyroid hormone.
Class III Antidysrhythmics uses
Ventricular tachycardia/fibrillation, atrial flutter/fibrillation. For treatment and maintenance.
Examples of Class III Antidysrhythmics
- Amiodarone (Cordarone)
- Brytelium
- Ibutiliade (Corvert)
- dofetilide (Tikosyn)
- satolol (Betapace)
Amiodarone side effects
- Related to size of dose and cumulative dose
- N/V GI distress, dizziness, hypotension, arrhythmia
- ↓ HR can proceed to 2nd or 3rd degree heart block (increases PR interval, QRS duration, and QT intervals
Amiodarone adverse reactions
- Hypothyroidism or hyperthyroidism
- Corneal microdeposits
- Hepatic dysfunction
- Pulmonary fibrosis (Destroys the capillaries in your lungs )
- Rarely seen with low dose 200mg/day - Peripheral neuropathy
- Proximal muscle weakness
Part of Amiodarone gets deposited in the __ after long term use (after __ year/s)
cornea
1
What is a rare adverse reaction of Amiodarone?
Blue-Gray Hyperpigmentation
they look cyanotic; for darker skinned people, the skin will become darker
amiodarone drug interactions
- Long half-life (weeks to months)
- Interacts with multiple drugs such as quinidine or digoxin
- Increased risk of QT prolongation with fluoroquinolones, macrolides, and azole antifungals
- Increases blood levels of Class I Antidysrhythmics including procainamide
- Increases blood level warfarin (Coumadin)
- Increased risk of QT prolongation with fluoroquinolones, macrolides, and azole antifungals
Note: Grapefruit juice inhibits enzymes in GI tract that metabolize amiodarone. Avoid concurrent use ↑ levels & risk of toxicity
Nursing considerations/patient education for Amiodarone
- For IV amiodarone – monitor IV site frequently
- Teach patient how to take pulse, monitor vitals
- Assess for neurotoxicity, monitor thyroid function, eye exams
- Note timing of meds – with or without food
- Monitor ECG during IV therapy or initiation of PO therapy
Heart rate & rhythm, prolonged PR & QT intervals, QRS widening - Assess for signs of pulmonary toxicity (shortness of breath)
Monitor Chest X-Ray & Pulmonary Function Tests
Amiodarone has a risk for causing ___ because it is very acidic
infiltration
Class IV Antidysrhythmics mechanism of action
blocks calcium channel in the heart muscle cells, leading to depression of depolarization and prolongation of phases 1 and 2 of repolarization, slowing conduction through the AV node. Think Ca channel blockers
Class IV Antidysrhythmic Uses
Ventricular tachycardia/fibrillation, atrial flutter/fibrillation and PSVT. Treatment and maintenance
Class IV Antidysrhythmic examples
- diltiazem (Cardizem)
2. verapamil (Calan) – given P.O. or IV
Class IV Antidysrhythmics prolongs __ __ and __. Slows down ___. Relaxes the __ __
phase 1 and 2
HR
blood vessels
Verapamil causes __ __. If you lower the bp too low, the HR will go up
rebound tachycardia
Antidysrhythmics: nursing interventions
- Give medications as scheduled
- Monitor vital signs
- Monitor ECG, liver & renal function
- Monitor drug levels of Procainamide and NAPA (metabolite)
- Check signs & symptoms of toxicity
Amiodarone is a Class III Antidysrhythmic because it has one of the following actions: A. Prolonged action potential duration B. Decreased action potential duration C. Prolonged NAPA excretion C. Decreased NAPA excretion
A. Prolonged action potential duration
A life threatening adverse reaction of the medication procainamide (Pronestyl, Procan SR) is: A. Nausea B. Anorexia C. Torsades de Pointes D. Vomiting
C. Torsades de Pointes
Anticoagulants: (3)
- antiplatelets
- antithrombin
- low-molecular weight heparin(LMWH) (Lovenox)
Thrombolytics examples
- r-tPA
2. streptokinase
Antihemophilic Agents example
coagulation factor VIIa
Systemic Hemostatic Agents
Aminocaproic acid
Topical Hemostatic Agents
Absorbable gelatin
What can you use to stop nosebleeds?
Aminocaproic acid
Thrombus Formation
How does a clot form in an artery or vein?
Caused by decreased circulation, platelet aggregation on vessel wall, blood coagulation
Arterial clot formation
- platelets initiate process
- fibrin formation occurs
- RBCs are trapped in fibrin mesh
Venous clot formation
platelet aggregation with fibrin that attaches to RBCs
venous clots are caused by RBCs by sluggish flow and they eventually become stuck together
If you have an MI, what do you give?
an ANTIPLATELET like aspirin
If you have a DVT, what can you give?
Plavix, heparin, compression socks
Clotting Cascade: Extrinsic Pathway
activated by external trauma that causes blood to escape from vascular system (bleeding)
Quicker than intrinsic pathway
Clotting Cascade: Intrinsic Pathway
activated by trauma inside vascular system. Activated by platelets, exposed endothelium, chemicals. Slower than extrinsic pathway
Clotting Cascade: Common pathway
completes clot production
Any form of blood escaping vessel activates the extrinsic pathway which will stimulate __ __. __ __ will be activated to __. __ will stimulate tissue factor and will be converted to factor __ (look at slide 63)
factor 7 factor 7 7A 7A 10A
When you are septic, you clot due to the __ __
intrinsic pathway
Composed of platelets and fibrin. Forms in vessels with high blood flow or in areas with atherosclerosis or plaque rapture. Activates the clotting cascade and platelet aggregation.
What kind of clot is this?
arterial thrombi
Composed of coagulated RBC and fibrin, few platelets and more fibrin. Forms in areas of low blood flow or stasis like the legs. Often associated with inflammation.
What kind of clot is this?
venous thrombi
The Joint Commission says:
- Take extra care with patients who take medicines to thin their blood.
- “High Alert” warning for blood thinners
3.Reported Sentinel Events Related to Anticoagulants (1997-2007)
Drugs Involved: Heparin 21, Warfarin 6, Enoxaparin 3, Unknown 2
Outcome: 34 Deaths= 28,lLoss of function= 6
Cause of Event: Wrong drug, wrong dose, improper monitoring, pump malfunction, given without order and meds not reordered
Anticoagulants do not
dissolve clots already formed
Anticoagulants prevent __ __ from __
new clots
forming
What activates platelet aggregation in the first place?
a ruptured plaque (atherosclerosis)
Heparin (unfractionated)
mechanism of action
Natural substance in liver & prevents clot formation; Inhibits thrombin (see next slide). Prevents conversion of fibrinogen to fibrin. Variable effect
Heparin (unfractionated) uses
for rapid anticoagulant effect in:
- DVT, Pulmonary Embolus (PE), or evolving stroke, DIC, atrial fib/flutter, MI, valve replacement and other thromboembolic states
- SQ prophylaxis - 5000 to 7500 units every 8 -12 hours (weight-based)
- IV therapy - acute thrombosis (MI/PE). Initial bolus of 80 units per kg, then 18 units per kg per hour by infusion based on aPTT. An aPTT of 1.5 to 2.0 times the control is desirable (60-80 seconds).
How does Heparin work?
- Heparin binds with Antithrombin III
- Antithrombin III inactivates thrombin
- Thrombin inhibits the conversion of fibrinogen to decrease fibrin
- clot prevented
Heparin (unfractionated) side effects
Itching, burning, and ecchymosis on the injection site
Heparin (unfractionated) adverse effects
Heparin -Induced Thrombocytopenia (HIT), bleeding. Highest in patients with any of the following: age >65, recent surgery, or conditions such as peptic ulcer disease, liver disease, neoplasia, and bleeding diathesis
Heparin (unfractionated) Interactions
Increased effect with aspirin, NSAIDs, thrombolytics, and probenecid
Heparin (unfractionated) Antidote:
Protamine Sulfate. 1-1.5 mg per 100 USP units of heparin; not to exceed 50 mg. Monitor aPTT 5-15 min after dose then in 2-8 hours.
How does a heparin injection produce a bruise?
Portion of the drug goes back up into the injection puncture site into the epidermis which causes a bruise
To prevent this, count to 5 before removing the plunger. Inject heparin where there is fat
If you give subQ heparin do you need to monitor PTT and aPTT?
No, because the heparin half life is only 30 minutes to 1 hours
We only monitor aPTT if we give __ __ . The goal is to make the aPTT __-__ seconds. You will do a blood draw every __-__ hours.
IV Heparin
60-80 seconds
4-6 hours
What is normal platelet levels
140,000 to 400,000
Heparin-induced Thrombocytopenia (HIT)
- It is a thrombotic disorder in 5-25% of patients on Heparin. An Allergic reaction
- Venous thrombosis is the main feature
- Immune-mediated response to Heparin
- Platelet factor 4 binds to Heparin, combined with IgG and creates an immune complex.
- This immune complex binds to circulating platelets (reducing the level and causing thrombosis).
For a patient with HIT, what can you give them ?
give them antithrombins
Why don’t use normally give blood thinners like heparin to patients who have liver failure?
b/c there is less production of certain clotting factors
Do not give heparin if the platelet is _____
For Heparin IV drip, ensure that a __ IV line and an __ __ is used.
Avoid ___ __ __ __
dedicated
infusion pump
interruption of the infusion
For Heparin IV drip, don’t __ anything with heparin
piggyback
HIT
Results in activation of more platelets and PF4 release =
thrombin forms
How can you rule out HIT?
if the level of platelets is less than 100,000 within 5-14 days of heparin tx
what is contraindicated in a person with HIT?
platelet transfusion
HIT can re-occur each time a patient receives heparin. This should be listed as a/an ___
allergy
What is the treatment for HIT?
Lepirudin inhibits thrombin and it’s thromboembolic effects. Given IV.
Low molecular weight heparin is __ which means :
fractionated
made of fragments/derivatives of unfractionated heparin
Mechanism of action for LMWH
Binds with antithrombin and accelerates the rate at which antithrombin inhibits Factor Xa and thrombin
LMWH uses
similar to heparin
example of a LMWH
Enoxaparin (Lovenox)
antidote for LMWH
Protamine Sulfate
compared to unfractionated heparin, LMWH: (4)
- less risk for bleeding
- more stable response
- does not require frequent aPTT monitoring
- 1/2 life 2-4X heparin
- thrombocytopenia less likely
Indications for LMWH
DVT prophylaxis
When you are stressed out, you are activating __ __ like __ and __. This makes you’re blood ___.
inflammatory mediators
cytokines, interleukins
hypercoagualable
Mechanism of action for Warfarin (Coumadin)
Inhibits the hepatic synthesis of coagulation factors dependent on Vitamin K: Factors II, VII, IX and X
Warfarin (Coumadin) 1/2 life
long 1/2 life and very long duration - (2-3 days?)
Warfarin (Coumadin) uses
mainly to prevent thromboembolic conditions such as embolism caused by atrial fibrillation, which can lead to a stroke (CVA), DVT, PE
Which clotting factors need vitamin K?
II
VII
IX
X
__ synthesizes and manufactures vitamin K
Liver
Coumadin aka Warfarin stems from the acronym WARF which stands for:
Wisconsin Alumni Research Foundation
Normal PT is
10-12 secodns
Normal INR (international Normalized ratio) -
0.7-1.7
Goals of Coumadin therapy:
- Atrial fibrillation - (2-3)
- Artificial valves - (2.5-3.5)
- DVT and PE - (2-3)
Goals of Coumadin therapy: start treatment at __ mg per day and titrate the dosage every __ to __ days to achieve goal
5 mg
3-7 days
Side effects of Coumadin
Anorexia, nausea, vomiting, diarrhea, abdominal cramps, rash, and fever
Adverse Effects of Coumadin
May increase AST (aspartate aminotransferase), ALT (alanine aminotransferase), and bleeding
Coumadin Antidote
Antidote: Vitamin K (2.5 to 10 mg IM or SQ). Fresh frozen plasma (FFP) is indicated for acute bleeding
What drugs if used with Coumadin would increase bleeding?
ASA H2 Blockers Erythromycin Cefoxitin Disulfiram Amiodarone Thyroid drugs Cotrimoxazole (Bactrim)
What drugs if used with Coumadin would decrease anticoagulation?
Vitamin K and E Rifampin Phynetoin Barbiturates Cholestyramine
Antiplatelet: Aspirin was discovered in the ___. Anti platelet properties was known in __.
1800s
1960s
Aspirin mechanism of action:
Inhibits platelet aggregation by interfering with thromboxane A2
Aspirin uses:
MI (bite and chew), CVA (tx or prophylaxis), CAD prophylaxis. Maybe used within 48 hours of stroke, recommended before and after endarterectomy
Aspirin side effects
tinnitus, bleeding
Aspirin adverse effects
nausea, dyspepsia, heartburn, GI bleed, tinnitus, toxicity, headache, anaphylactoid reaction.
Aspirin antidote
No Antidote. Discontinue 1wk before surgery
Aspirin is rapidly absorbed in the GI tract
onset: __-__minutes
5-30 minutes
Aspirin inhibits platelets within __ minutes (Peak: __ min to __ hours)
60 minutes
25 minutes - 2 hours
Duration of Aspirin
3-6 hours
Plavix is a __ which is an _____ drug
thienophyridine
anti platelet drug
Plavix mechanism of action
Prevents platelet aggregation by blocking Adenosine Diphosphate from binding to platelet receptor
Examples of Thienophyridines
- dipyridamole (Persantine)
- ticlopidine (Ticlid)
- clopidogrel (Plavix)
Plavix has similar side effects and adverse reactions with __
Aspirin
Onset of action for Plavis is __ __ and drug effects last for __ __
several days
7 days
Patients allergic to Aspirin can take __
Plavix
__ also allows for platelets to stick together
ADP
Direct acting thrombin inhibitors are ___ (_) __
Parenteral (IV) Anticoagulants
Direct Acting Thrombin Inhibitors mechanism of action
directly inhibit thrombin from converting fibrinogen to fibrin
Direct Acting Thrombin Inhibitors Uses
Heparin-induced thrombocytopenia, unstable angina, angioplasty
Direct Acting Thrombin Inhibitors examples
- Argatroban (Acova)
- bivalirudin (Angiomax)
- lepirudin (Refludan).
SQ: Desirudin (Iprivask).
PO: Pradaxa
__ __ is a contraindication for lepirudin
Liver failure
Dabigatran Etexilate (Pradaxa) category
direct thrombin inhibitor
Dabigatran Etexilate (Pradaxa) uses
non-valvular atrial fibrillation and stroke treatment and prophylaxis, HIT, DVT, and PE
Dabigatran Etexilate (Pradaxa) is metabolized in the
liver
Dabigatran Etexilate (Pradaxa) 1/2 life
12 – 17 hours (longer in the elderly) and renal impairment
Dabigatran Etexilate (Pradaxa) excreted in the urine. Severe Renal failure =
risk for bleeding
Dabigatran Etexilate (Pradaxa) dosage
150 mg twice daily P.O.
Factor XA Inhibitor Oral Anticoagulants examples
Rivaroxaban (Xarelto) and Apixaban (Eliquis
Factor XA Inhibitor Oral Anticoagulant uses
DVT and PE prophylaxis in patients
going for hip/knee surgery, stroke, atrial fibrillation, and non-valvular fibrillation
Does Factor XA Inhibitor Oral Anticoagulant require routine coagulation monitoring?
no
Factor XA Inhibitor Oral Anticoagulant is administered:
once daily or twice a day P.O. (10-20 mg depending on indication)
General contraindications for anticoagulants:
- Bleeding disorders
- Peptic ulcer
- Severe hepatic or renal disease
- Hemophilia
- CVA
- Eye, brain, or spinal surgery
- Risk for injury from fall
Nursing assessment for Anticoagulants
Hx clotting or bleeding
Drug & herb use
Baseline labs: CBC, Coags, LFTs, renal labs
Heparin:
Activated partial thromboplastin time (aPTT)
Warfarin: PT or INR
Nursing Diagnoses for Anticoagulants
Risk for injury (bleeding)
Knowledge deficit
Evaluation
aPTT, PT/INR are within therapeutic range
Nursing Care (8)
- Use soft toothbrush, electric razor, ID bracelet
- Observe the Five “Rs” and Right “REASON”
- Assess for allergies and history of Heparin induced thrombocytopenia (HIT)
- Assess fro S/S of bleeding, thrombosis and embolism (Pulmonary)
- Current medication regimen including OTC (Ginko, Garlic, Ginseng= increase bleeding with Coumadin)
- Increase effect=NSAIDS, Tylenol, PCN, Prilosec
- Check for baseline INR,PT, aPTT, CBC and Platelet count
- Do not give IM injections of any drugs?
Thrombolytics mechanism of action
Promote fibrinolytic mechanism. Convert plasminogen to plasmin to dissolve clot
Thrombolytics uses:
A. Myocardial infarction (best within 1 hour)
B. thromboembolic stroke (best within 3 hours)
C. pulmonary embolism
D. DVT
E. non-coronary arterial occlusion from an acute thromboembolism
F. restore patency of central lines
Examples of Thrombolytics
- Streptokinase (Streptase)
- Alteplase tPA (Activase)
- Reteplase rPA (Retavase)
Indications for tPA
heart attack
strokes
You don’t want to give thrombolytics platelets is >
1.7
Thrombolytics prototype:
Alteplase
Thrombolytics short 1/2 life
30-45 minutes
Excretion of Thrombolytics
urine
Thrombolytics side effects
bleeding
thrombolytics adverse reactions
- intracerebral hemorrhage
- stroke
- dysrhythmia
Thrombolytics assessment
Baseline vital signs, CBC, PT, INR, PTT, obtain medical and drug history
Thrombolytics Nursing diagnoses
Patient hemodynamically unstable due to clot
Thrombolytics Interventions
Administer drug, monitor for bleeding, neuro status, labs
Thrombolytics
What do you evaluate for?
Vital signs remain stable, labs within acceptable range
The nurse is preparing to administer heparin sodium to a client diagnosed with a deep vein thrombosis. The nurse should ensure that which of the following is available if the client develops a significant bleeding problem?
A. Phytonadione (vitamin K)
B. Fresh frozen plasma (FFP)
C. Protamine sulfate
D. Reteplase (Retavase)
C. Protamine sulfate
The nurse will expect to draw the following laboratory value 6 hours after starting the heparin drip? A. PT/INR B. aPTT C. Serum potassium D. Serum sodium
B. aPTT
The patient is now taking Coumadin in preparation for discharge. The nurse knows that which of the following nursing diagnoses takes priority? A. Risk for imbalanced fluid volume B. Risk for injury C.Constipation D. Risk for unstable blood glucose
B. risk for injury
(MY GUESS) answer was not provided
The nurse is preparing to discharge the client to home on warfarin (Coumadin) therapy. The nurse’s discharge teaching should include which of the following instructions?
A. The intake of foods containing vitamin K should not be altered from baseline
B. Herbal medications may interfere with the effectiveness of Coumadin
C. Alcohol can increase the anticoagulant effect of Coumadin and should be avoided
D. Coumadin can be taken without regard to food intake, although gastrointestinal upset may be diminished if taken with food
B. Herbal medications may interfere with effectiveness of Coumadin
(MY GUESS) answer was not provided
Clotting Factor I
Fibrinogen
Clotting Factor II
Prothrombin
Clotting Factor III
Tissue Thromboplastin
Clotting Factor IV
Calcium Ions
Clotting Factor V
Labile Factor
Clotting Factor VII
Stable Factor
Clotting Factor VIII
Antihemophilic Factor
Clotting Factor IX
Christmas Facor of Plasma Thromboplastin Component (PTC)
Clotting Factor X
Stuart-Prower Factor
Clotting Factor XI
Plasma Thromboplastin Antecedent (PTA)
Clotting Factor XII
Hageman Factor
Clotting Factor XIII
Fibrin Stabilizing Factor