PHARMACOLOGY LAB
Drugs Acting on the cardiovascular system
Action Potential in Cardiac Muscle
Arrhythmia
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problem with the rate or rhythm of
your heartbeat.
heart beats too quickly, too slowly, or
with an irregular pattern.
No effect of depolarization and on action
potential duration
1. Flecainide (Tambocor) initially developed as a
local anesthetic. It slows conduction in all parts
of heart
2. Propafenone
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Also slows conduction
Weak β – blocker
>Tachycardia- heart beats faster than
normal
Class II – β–adrenergic blockers
> Bradycardia- heart beats too slowly
1.Propranolol (Inderal)
> atrial fibrillation- common type of
arrhythmia. causes an irregular and fast
heart beat.
Antiarrhythmic Drugs
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affect the action potential of the cardiac
cells, altering their automaticity,
conductivity, or both
antiarrhythmics can cause arrhythmia!
be vigilant in determining dosing, blood
levels, and in follow-up
Classification of Antiarrhythmics (Based on
Mechanisms of Action)
Class I – Blocker’s of Fast Na+ Channels
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Slows SA node and ectopic pacemaking
Can block arrhythmias induced by
exercise or apprehension
2. Other β–adrenergic blockers have similar
therapeutic effect:
3. Metoprolol (Betaloc, Cardiosel, Neobloc)
4. Atenolol (Tenormin, Therabloc)
5. Pindolol (Visken)
Class III – K+ channel blockers
- Block potassium channels and slow the
outward movement of potassium during phase
3 of the action potential, thereby prolonging it
Subclass IA
-Prolong repolarization
- Developed because some patients are
sensitive to Na channel blockers (they died!)
-Increased duration of action potential
1.Amiodarone – drug of choice for treating
ventricular fibrillation or pulse less ventricular
tachycardia in cardiac arrest situations
1. Quinidine – 1st antiarrhythmic used to treat
both atrial and ventricular arrhythmias
2. Procainamide
3. Disopyramide
> Subclass IB
Shortened depolarization
Decreased action potential duration
1. Lidocaine (local anesthetic) - is good for
digitalis-associated arrhythmias. Used in lifethreatening ventricular arrhythmias during
myocardial infarction or cardiac surgery; also
used as a bolus injection in emergencies
2. Mexiletine –approved only for use in lifethreatening ventricular arrhythmias in adults
3. Phenytoin
> Subclass IC
2. Bretylium
3. Dofetilide
4. Sotalol
Class IV – Ca+ Channel Blockers
- Block the movement of calcium ions across
the cell membrane
- decreasing the excitability and contractility of
the myocardium
- Slow the rate of AV-conduction in patients
with atrial fibrillation
1. Verapamil (Isoptin) – blocks Na+ channels in
addition to Ca2+, also slows SA node in
tachycardia
2. Diltiazem (Dilzem)
PHARMACOLOGY LAB
-There is a risk of severe cardiac effects if these
drugs are given IV within 48 hours of IV betaadrenergic drugs.
Nursing Implementation
1. Titrate the dose to the smallest amount
needed to decrease the risk of severe adverse
effects.
2. Continually monitor cardiac rhythm when
initiating or changing dose to detect potentially
serious adverse.
3. Ensure that emergency life support
equipment is readily available.
4. Administer parenteral forms as ordered only
if the oral form is not feasible.
5. Consult with the prescriber to reduce the
dose in patients with renal or hepatic
dysfunction
-reduced dose may be needed to
ensure therapeutic effects without
increased risk of toxic effects.
6. Establish safety precautions, including side
rails, lighting, and noise control.
7. Arrange for periodic monitoring of cardiac
rhythm when the patient is receiving long-term
therapy to evaluate effects on cardiac status.
- The most common etiology of coronary
artery disease (CAD) in adults is atherosclerosis,
the presence of plaque – a fatty, fibrous
material within the walls of the coronary
arteries.
- Plaque develops progressively over time,
producing varying degrees of intravascular
narrowing, and a situation that results in partial
or total blockage of the vessel.
> These drugs can work to improve blood
delivery to the heart muscle in one of two ways:
1. By dilating blood vessels ( increasing the
supply of oxygen)
2. By decreasing the work of the heart
(decreasing the demand for oxygen)
Anti-Angina Drugs come in many different
forms:
1. tablets and capsules that are
swallowed;
2. tablets that are held under the tongue,
inside the lip, or in the cheek until they
dissolve;
3. stick-on patches; and sprays
Nitrates
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Antianginal Drugs
What is Angina?
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> Increase demand of 02
> Decrease 02 supply
- Coronary Artery Disease (CAD) is
characterized by narrowing or occlusion of a
coronary artery.
- The narrowing deprived cells of oxygen and
nutrients, also known as myocardial ischemia.
- If ischemia develops over a long period of
time, the heart may compensate for its
inadequate blood supply, and the client may
experience no symptoms.
- As CAD progresses, the myocardium does not
receive enough oxygen to meet the metabolic
demands of the heart, and symptoms of angina
begin to appear.
-Persistent myocardial ischemia may lead to
heart attack.
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act directly on smooth muscle to cause
relaxation and to depress muscle tone.
the action is direct, these drugs do not
influence any nerve or other activity,
and the response is usually quite fast.
 Also termed as vasodilators
Commonly used Anti-Angina Drugs
Isosorbide dinitrate (Isordil)
Isosorbide mononitrate (Imdur)
Nitroglycerin (Nitrostat, Nitro-Bid)
Adverse Effects
CNS: Headache, dizziness, weakness
GI: Nausea, vomiting, incontinence
Cardiovascular: Hypotension which can be
severe and must be monitored;
-reflex tachycardia that occurs when blood
pressure falls;
-syncope and angina which could be
exacerbated by the hypotension and changes in
cardiac output
PHARMACOLOGY LAB
Sublingual
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usual protocol for administering
nitroglycerin tablets
administer one tablet every 5 minutes
as needed
total dose of three tablets
Onset of action is within 1-3 minutes
duration of action is 30-60 minutes
Nursing Interventions
1. Give sublingual preparations under the
tongue or the buccal pouch.
2. Offer sips of water before giving
sublingual nitroglycerin because
dryness may inhibit drug absorption
3. Ask the patient if the tablet “fizzles” or
burns, which indicates potency. protect
the medication from heat and light.
4. Instruct the patient that a sublingual
dose may be repeated in 5 minutes if
relief is not felt, for a total of 3 doses; if
pain persists, the patient should go to
an emergency room to ensure proper
medical support if an MI occur.
Transdermal Patch
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Wash hands thoroughly before and
after applying.
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Apply the patch to the chest, inner side
of the upper arm, or shoulder.
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Clean and dry the skin before applying
the patch. If necessary, hair may be
removed.
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Change the treatment site daily. Do not
apply to irritated or damaged skin
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If the patch becomes loose, remove it
and apply a new patch at a different
site.
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After you remove the used patch, fold
the sticky side together and throw
away.
Should only be worn for up to 12 to 14
hours a day, or as directed by your
doctor so that the client will have a 10
to 12 hour "nitrate-free" period each
day. This will prevent client tolerance to
nitrates.
Lipid Lowering Agents
Antihyperlipidemics
LIPIDS
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Cholesterol and other fatty acids
not soluble in liquid
they are carried in the plasma by linking
lipoproteins (albumins and globulins).
Lipoproteins- described by how thick
and dense they are (“high density
lipids” and “low-density lipids”)
The body needs a certain amount of
cholesterol and triglycerides
Four Major Types of Lipoprotiens
1. Chylomicrons -largest and lightest of
the lipoproteins.
-Formed from the absorption of dietary
fat in the intestine and are mostly
triglycerides.
-Normally present in plasma for only 1
to 8 hours after the last meal.
2. Very low-density lipoproteins (VLDLs)
made up of large amounts of
triglycerides that were made in the liver
3. Low-density lipoproteins (LDLs). When
VLDLs break down and link with
cholesterol and protein, very little
triglyceride is left. High serum levels of
LDLs indicate cholesterol levels that are
higher than the body needs. Paients
with high LDL levels are at high risk for
developing atherosclerosis.
4. High-density lipoproteins (HDLs) are
small, dense lipoproteins and contain
very small parts of triglycerides. The
“vacuum cleaners” of the tissues,
clearing out excess cholesterol.
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Chylomicrons and VLDLs are seen as
triglyceride-rich lipoproteins
LDLs and HDLs are cholesterol-rich
lipoproteins
LDLs move cholesterol from the liver to
the peripheral tissues
HDLs remove cholesterol from the
periphery and transport it to the liver
Hyperlipidemia used to describe an
increase in levels of lipoproteins in the
blood.
PHARMACOLOGY LAB
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It leads to atherosclerosis and patients
with damage to the lining of their
vascular walls have a gradual build up of
fatty deposits within the lining of the
vessel walls of the arterial system.
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This will lead to the onset of angina that
results from ischemic heart disease,
cerebrovascular disease, peripheral
ischemia, and renovascular
hypertension.
Types of Antihyperlipidemic Drugs
1. Bile Acid Sequestrants
2. HMG – CoA ( hydroxymethylglutartyl –
CoEnzyme A)Reductase Inhibitors
3. Fibric acid derivatives
4. Niacin
Bile Acid Sequestrant
Cholestyramine (Questran)
Colestipol (Colestid)
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Reduce serum cholesterol levels by
forming an insoluble compounds with
bile salts and increasing bile loss
through the feces.
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This results in decrease LDL plasma
levels of at least 20% and serum
cholesterol levels
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no longer considered first-line drugs for
dyslipidemia
Side Effects:
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Bloating, Constipation, Abdominal pain,
Nausea, Vomiting, Diarrhea,
Steatorrhea or excessive fat in the
stool.
Nursing Implementation
1. Do not administer powdered agents in
dry form. Mix with fruit juices, soups,
liquids, cereals, or pulpy fruits. Do not
mix cholestyramine, with carbonated
beverages. Encourage the patient to
swallow all of the dose.
2. Ensure that tablets are not cut, chewed,
or crushed because they are designed
to be broken down in the GI tract
3. Administer other oral medications 1
hour or 4 hours after taking bile acid
sequestrants to avoid interference of
other drugs.
4. Arrange for a bowel program as
appropriate to effectively deal with
constipation if it occurs.
5. Inform client to follow a high-bulk diet
and drink lots of fluids.
6. Advise client to immediately report
yellowing of the skin or eyes to evaluate
possible adverse effects
HMG-CoA Reductase Inhibitors
1. Simvastatin ( Zocor) for lowering
cholesterol and preventing MI in
patients with known
hypercholesterolemia and CAD
2. Atorvastatin (Lipitor) associated with
severe liver complications but can be
used to lower cholesterol levels in
children 10 to 17 years of age
3. Rosuvastatin (Crestor) the newest
statin and lowers LDL and raise HDL
slightly better than the other statins
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Statins should be administered in the
evening because cholesterol
biosynthesis in the body is higher at
night
Minor side effects include headache,
fatigue, muscle or joint pain
Serious adverse effects are severe
myopathy and rhabdomyolysis.
Liver dysfunction may occur with the
use of statin drugs, monitor liver
function tests before and during the
first few months of therapy
Statin drugs should not be used in
clients with active liver disease or
unexplained elevations in liver function
tests
Nursing Implementation
1. Administer the drug at bedtime
because the highest rates of cholesterol
synthesis occur between midnight and
5 AM,
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drug should be taken when it will
be most effective; but atorvastatin
PHARMACOLOGY LAB
can be given at any time during the
day
2. Monitor serum cholesterol and LDL
levels before and periodically during
therapy to evaluate the effectiveness of
the drug.
3. Monitor liver function tests before and
periodically during therapy
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consult with the prescriber to
discontinue the drug if the
aspartate aminotransferase (AST) or
alanine aminotransferase (ALT)
level increases to three times
normal.
4. Ensure that the patient has attempted a
cholesterol lowering diet and exercise
program for at least 3 to 6 months
before beginning therapy to ensure the
need for drug therapy.
5. Withhold lovastatin, atorvastatin, or
fluvastatin in any acute, serious medical
condition (e.g., infection, hypotension,
major surgery or trauma, metabolic
endocrine disorders, seizures) that
might suggest myopathy or serve as a
risk factor for the development of renal
failure.
6. Suggest the use of barrier
contraceptives for women of
childbearing age because there is a risk
of severe fetal abnormalities if these
drugs are taken during pregnancy.
7. Arrange for periodic ophthalmic
examinations to monitor for cataract
development.
8. Provide comfort measures. These
include small, frequent meals to
minimize nausea and vomiting
-access to bathroom facilities to ensure
adequate bowel evacuation;
-give food if GI upset is severe to decrease
direct irritating effects;
- temperature and lighting controls, to help
deal with headaches;
-activity restrictions, to protect the patient
if vision changes and muscle effects occur.
Fibric acid derivatives
1. Ezetimibe (Ezetrol, Vytorin) decreasing
the absorption of dietary cholesterol,
leading to a drop in serum cholesterol
levels.
2. Fenofibrate (Lipanthyl) inhibits
triglyceride synthesis in the liver,
resulting in reduction of LDL levels
3. Gemfibrozil (Lopid) inhibits peripheral
breakdown of lipids, reduces
production of triglycerides and LDLs and
increases HDL concentration.
-Fenofibrate and Gemfibrozil are well
tolerated but can cause liver toxicity and
cholelithiasis (gallstones)
Niacin (Vitamin B3 )
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One of the most effective
antihyperlipidemics at lowering
triglyceride levels and increasing HDL
levels.
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Similar to bile acid sequestrants in its
ability to lower LDL levels.
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Adverse effect: flushing, which occurs
shortly after the drug is taken and can
be reduced by taking aspirin (30
minutes before) and increasing the
niacin dosage very slowly over 3 to 4
weeks.
Client Teaching for Antihyperlipidemic Drugs
1. Teach client to take vitamins A, D, and K
as supplements if antihyperlipidemic
drugs are to be taken for long period of
time.
2. bile acid sequestrants are to be taken
3x a day before meals.
3. Instruct client that bile acid
sequestrants come as a powder and
should be added to a liquid. Allowing
the power to dissolve slowly without
stirring.
4. Instruct patients to take any other
medicine 1 hour before or 4 to 6 hours
after taking antihyperlipidemics since
these medicines are like glue and will
delay the absorption of other drugs if
taken at the same time.
PHARMACOLOGY LAB
Drugs for Coagulation Disorders
The three major groups are
Blood Clot Formation
(1) anticoagulants,
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(2) antiplatelet,
Hemostasis, or the stopping of blood
flow and is an essential mechanism that
protects the body from both external
and internal injury.
(3) thrombolytics
Anticoagulants
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Without efficient hemostasis, bleeding
from wounds or internal injuries would
lead to shock and perhaps death
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Drugs used to prolong bleeding time
and thereby prevent blood clots from
forming
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Hemostasis is a complex process
involving a number of clotting factors
that are activated in a series of
sequential steps, sometimes referred to
as a cascade
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Also called as blood thinners
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Do not dissolve clots that have already
formed, but rather act prophylactically
to prevent new clots from forming
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Used in patients with venous and
arterial disorders that put them at high
risk for clot formation
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Venous problems such as thrombosis,
pulmonary embolism, & arterial
problems like coronary thrombosis,
and MI
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Contraindicated with active bleeding,
except for DIC, bleeding disorders, or
blood dyscracias, ulcers, liver and
kidney disease
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Side effects: hemorrhage, hematuria,
epistaxis, ecchymosis, bleeding gums,
thrombocytopenia
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Too much clotting can be just as
dangerous
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Diseases can affect hemostasis like MI,
cerebrovascular accident (CVA), venous
thrombus, valvular heart disease
4 Steps to Hemostasis
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1. Vessel injury
2. Vessel Spasm
3. Platelets adhere to injury site
and aggregate to form plug
4. Formation of insoluble fibrin
strands and coagulation.
Hemostasis is achieved once a
blood clot is formed, protecting the
body from excessive hemorrhage
The clot may restrict blood flow to
the affected area; circulation must
eventually be restored so that the
tissue can resume normal activities
The process of clot removal is called
fibrinolysis. It is initiated within 24
to 48 hours of clot formation and
continues until the clot is dissolved
Disorders that directly affect the coagulation
process fall into two main categories:
Warfarin (Coumadin)
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Oral drug
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Works by interfering with the formation
of vitamin K-dependent clotting factors
in the liver
Vitamin K is used to reverse the effects of
warfarin.
Coumadin
1. conditions that involve overproduction
of clots, or thromboembolic disorders;
2. conditions in which the clotting process
is not working effectively, resulting in
risk for excess bleeding or hemorrhagic
disorders.
-Various drugs are used to maintain or restore
circulation
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A longer than normal prothrombin time
(PT) can mean a lack of or low level of
PHARMACOLOGY LAB
one or more blood clotting factors
(factors I, II, V, VII, or X).
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It can also mean a lack of vitamin K or
due liver disease, such as cirrhosis; or
that a liver injury has occurred
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It can be due to Disseminated
Intravascular Coagulation (DIC)
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It can also be caused by treatment with
blood-thinning medicines, such as
warfarin (Coumadin) or, in rare cases,
heparin.
Anticoagulants
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Dabigatran (Pradaxa) directly inhibits
thrombin, which blocks the last step to
clot formation
 It is approved to reduce the risk
of stroke and systemic
embolism in patients with
nonvalvular atrial fibrillation
(AF)
 Drug of choice over warfarin for
treating this condition
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Rivaroxaban (Xarelto) is a factor Xa
inhibitor that stops the coagulation
cascade at this early step.
 Approved to prevent deep vein
thrombosis, which might lead
to pulmonary embolism, in
patients undergoing knee or hip
replacement surgery.
Heparin
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Heparin is a naturally occurring
substance that inhibits the conversion
of prothrombin to thrombin, thus
blocking the conversion of fibrinogen to
fibrin – the final step in clot formation
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Injected IV or subcutaneously and has
an immediate onset of action
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Low molecular weight heparin like
Enoxaparin given subcutaneously do
not require the same intense
monitoring like heparin
The activated partial thromboplastin time
(aPTT)) is a screening test that helps
evaluate a person's ability to appropriately
form blood clots. It measures the number of
seconds it takes for a clot to form in a
sample of blood. The aPTT assesses the
amount and the function of certain proteins
in the blood called coagulation or clotting
factors.
Nursing Implementation
1. Evaluate for therapeutic effects of
warfarin like the prothrombin time (PT)
1.5 to 2.5 times the control value or
ratio of PT to International Normalized
Ratio (INR) of 2 to 3 to evaluate the
effectiveness of the drug dose.
2. Evaluate for therapeutic effects of
heparin like the activated partial
thromboplastin time which is 1.5 to 3
times the control value to evaluate the
effectiveness of the drug dose.
3. Evaluate the patient regularly for any
sign of blood loss like petechiae,
bleeding gums, bruises, dark-colored
stools, dark-colored urine
4. Provide safety measures, such as use of
an electric razor and avoidance of
contact sports to decrease the risk of
bleeding.
5. Provide increased precautions against
bleeding during invasive procedures;
use of pressure dressings; avoid IM
injections; and do not rub subcutenous
injection sites
Thrombolytic Medications
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Therefore, it saves laboratory costs as
well as nursing time
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Protamine sulfate is the antidote for
heparin overdose
Process of Fibrinolysis
PHARMACOLOGY LAB
Thrombolytic Medications
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The general action of thrombolytic
agents is the selective degradation of
formed fibrin clots with minimal effect
on clot formation.
Administered for disorders in which an
intravascular clot has already formed
such as in acute myocardial infarction,
pulmonary embolism, acute ischemic
cerebrovascular accident (CVA), and
deep vein thrombosis (DVT )
Used early in the course of myocardial
infarction within 4 to 6 hours of the
onset of the infarct to restore blood
flow
This time limitation is not related to
drug activity, because thrombolytic
agents can break down clots older than
6 hours. Rather, tissue that has been
anoxic for more than 6 hours is not
likely to benefit from this therapy,
making the risks to the client greater
than the advantages.
The goal of thrombolytic therapy is to
quickly restore blood flow to the tissue
served by the blocked vessel.
Contraindications: active internal
bleeding, history of CVA, intracranial
problems, trauma within the previous 2
months
Alteplase
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If administered within 3 hours of onset
of ischemic stroke, significantly
improves clinical outcomes especially
the patient’s ability to perform activities
of daily living
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Adverse effects: Bleeding complications
including GI and cerebral hemorrhages
Streptokinase
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Therapy is instituted within 4 hours of
myocardial infarction and is infused for
one hour
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Thromboplastin time is monitored and
maintained at 2-5 fold the control value
4. Fondaparinux (Arixtra) a specific blocker of
factor Xa for the prevention of venous
thromboembolic events in patients undergoing
surgery for hip fracture, hip or knee
replacement.
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Antidote: Aminocaprioc acid (Amicar)
Antiplatelet Medications
THROMBUS: is the clot that adheres to the
vessel wall
EMBOLUS: is the CLOT that floats in the blood
THROMBOSIS: is the formation of unwanted
clot within the blood vessel, producing life
threatening conditions such as:
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Acute myocardial infarction
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Acute ischemic stroke
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Deep vein thrombosis
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Pulmonary embolism
Antiplatelet Medications
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Inhibit the aggregation of platelets in
the clotting process, thereby prolonging
bleeding time
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Used in the prophylaxis of long-term
complications following MI and CVA
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Contraindicated in bleeding disorders
and known sensitivity
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Side effects: GI bleeding, bruising,
hematuria, tarry stools
1. clopidogrel (Plavix) - used in patients
who are at risk for ischemic events and
those with a history of MI
2. cilostazol (Pletaal) - indicated for the
reduction of symptoms of intermittent
claudication, allowing increased walking
distance
3. acetlysalicylic acid (Aspirin) - is
effective in decreasing incidence of
Transient Ischemic Attack (TIAs)
Adverse Effects
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Most common adverse effect is
bleeding, which often occurs as
increased bruising and bleeding while
brushing the teeth.
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Headache
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Dizziness
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Weakness
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Nausea
PHARMACOLOGY LAB
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GI distress
Adverse Effects of Aspirin
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Nausea
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Dyspepsia
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Heartburn
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Epigastric discomfort
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GI bleeding
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Occult blood loss
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Dizziness
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Tinnitus
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Difficulty hearing
Nursing Interventions
1. Suggest safety measures, including the
use of an electric razor and avoidance
of contact sports.
2. Provide increased precautions against
bleeding during invasive procedures;
use pressure dressings and ice to
decrease excessive blood loss caused by
anticoagulants.
3. Provide small frequent meals to relieve
GI discomfort