Download Unit 4 Antidysrhythmic and Antihypertensive Agents

NURS 1950 Pharmacology
Nancy Pares, RN, MSN


Heart beat arises outside the sinoatrial (SA)
node
Terms:
◦ Inotropic
◦ Chromotropic
◦ Domotropic


Arrhythmia or dysrhythmia
Variation of normal rhythm-usually
associated with cardiac
◦ An electrical activity initiated by a spontaneous
discharge



Decrease the automaticity of the cardiac
tissues distant from the sinoatrial node.
Alter the rate of conduction thru the heart
Alter the refractory period between
consecutive contractions.

Classed according to action
◦ Class I: myocardial depressents-inhibit sodium ion
movement preventing depolorization
 Ia: prolongs electrical stimulation (in cell)
prolongs refractory time between impulses –delays
repolarization
Ib: shortens the duration of the e-stimulation and
the time between impulses—accelerates repolerization
Ic: most potent-slows conduction rate through atria and
ventricles—no effect on repolorization
Class II: beta-andrenergic blocking agents
-block sympathetic stimulation (slows
conduction and decreases HR
Class III: slows the rate of electrical conduction
and prolongs refractory time
-potassium channel blocking
Class IV:blocks calcium ion flow-prolongs elec
stimulation and slows AV node conduction
Misc: Adenosine and Digoxin: not related to
any other agents

Objective 5: List the side effects of
antirrhythmics

Includes:
◦
◦
◦
◦
Disopramide phosphate (Norpace)
Procainamide HCL (Pronestyl)
Quinidine gluconate (Duraquin)
Quinidine polygluconate (Cardioquin)
◦ Prototype: Procainamide (Pronestyl)


-derived from the cinchona bark
-cardiac depressant effects: reduces
excitability of the cardiac muscle, prolongs
refractory period between consecutive
contractions
◦ Allows the sinoatrial node to take over


Used for atrial tachycardia, flutter and
fibrillation.
Side effects severe: 1/3 of clients must d/c
use

S/E:
◦ GI distress
◦ CV disorders
◦ Rashes, respiratory arrest, hemolytic anemia,
agranulocytosis
◦ Hypersensitivity
 Cinchonism: tinnitus, nausea, HA, dizziness
impaired vision, vertigo

Nursing Implications:
◦ Can reduce problems if nurse:




Avoid use in CHF patients
Monitor digitalis levels (if on digitalis)
Monitor potossium (K+) levels
Monitor sodium (Na+) levels

Routes:
◦ Oral with meals
◦ Parenteral: give slowly


Uses:ventricular arrhythmias (best), atrial
fibrillation(helpful), paroxysmal atrial
tachycardia (PAT)
S/E: GI distress, ventricular tachy,
hypotension and hypersensitivity
◦ Allergy most likely if allergic to ‘caine’ drugs (related to
local anesthetics)
◦ Can cause agranulocytosis: lupus like syndrome



S/E: hypotension, tachyarrythmias,
anticholinergic effects
Has lower incidence of adverse effects than
quinidine or procainamide
Oral dosing




Lidocaine (Xylocaine)
Mexiletine (Mexitil)
Phenytoin (Dilantin)
Tocainide (Tonocard)


Use:Preventricular contractions (PVC), cardiac
glycoside-induced tachyarrhythmias,
cardioversion
Action: very rapid onset (IV), short acting
◦ Shortens the duration of elec stim
◦ Gives precise control of cardiac status

S/E/Route:
◦
◦
◦
◦
Excessive decrease in cardiac electrical conductivity
Hypotension, bradycardia, dizziness; CNS effects
Hypermetabolism (malignant hyperthermia
ineffective if given orally (metabolized in liver)

Nursing Interventions:
◦ Continuous EKG
◦ Look at bottle before giving-should not contain
preservatives or epinephrine
-standard classification is neuroleptic, but
used for arrythmias caused by cardiac
glycoside intoxication
Action: decreases automaticity of cardiac
muscle, increases rate of conduction of the
cardiac electrical impulses

S/E/ Route:
◦ Neurological disturbances: peripheral neuropathy,
diplopia, ataxia, vertigo, drowsiness, confusion
◦ GI disturbances
◦ Skin rash


Similar to lidocaine
Nursing Interventions:
◦ Given orally only
◦ Monitor EKG
◦ Client teaching: s/e and when to call MD

S/E:
◦ Dizziness, nausea, parethesia, numbness, restlessness,
tremor, GI distress, blood dyscrasias
◦ Should not be used in 2nd or 3rd degree AV block without a
pacemaker



Action: similar to lidocaine
Use: ventricular arrhythmias
S/E/route:
◦ N/V, heartburn, dizziness, tremor, impaired
coordination
◦ Given orally

Flecainide (Tambocor)

Encainide (Enkaid)

Rythmol



Action: local anesthetic
Use: ventricular arrhythmias
S/E/route:
◦ Can cause new or worsen arrhythmias
◦ High degree of negative inotropy
◦ Dizziness, visual disturbances, HA, nausea, fatigue,
chest pain





Local anesthetic, membrane stabalizing,
some beta blocking effect
Use: life threatening ventricular arrhythmias
S/E: may cause new or worsen existing
arrhythmias, dizziness, GI disturbances, may see
1st degree AV block
Nursing Interventions: monitor with EKG
Contraindications: uncontrolled CHF, brady,
bronchospasm, severe hypotension




Acebutolol (Sectral)
Esmolol (Brevibloc)
Propranolol (Inderal)
Action:
◦ Inhibits cardiac response to sympathetic nerve
stimulation by blocking the beta receptors; reduces
heart rate, systolic BP and cardiac output.

Use:
◦
◦
◦
◦
◦
Ventricular arrhythmias
Sinus tachycardia
Paroxysmal atrial tachycardia (PAT)
Premature ventricular contractions (PVC)
Tachycardia associated with atrial flutter,or
fibrillation

S/E:
◦ What would we expect to see?
 Slow HR, orthostatic hypotension, SOB, painful
urination, wt gain > 2 lbs/day, insomnia, drowsiness,
confusion
 Mask the signs of hypoglycemia

Nursing Interventions:
 Take pulse and report below 50, rise slowly, report
symptoms, diabetics monitor BS closely

Amiodarone (Cordarone)

Dofetilidide (Tikosyn)

Sotalol (Betaspace)

Action:
◦ Prolongs the action potential of the atrial and
ventricular tissues
◦ Antagonizes (non competitive) the alpha and beta
receptors causing vasodilation

Use:
◦ Life threatening arrythmias non responsive to other
agents

S/E/Route:
◦ Fatigue, tremors, sleep disturbances, numbness,
ataxia, confusion, exertional dyspnea, nonproductive cough, pleuritic chest pain,
photosensitivity
◦ s/e often cause clients to d/c use
◦ > 400mg/day cause problems
◦ Given oral or IV

Nursing interventions:
◦
◦
◦
◦
◦
Loading dose is needed
Watch monitor for new arrhythmias
Dose adjustment is difficult
Monitor/teach about post treatment arrhythmias
Wear sunscreen

Action/Use:
◦ slows conduction through the AV node causing
relaxation of the coronary and peripheral vessels
◦ Dysrhythmias

S/E:
◦ HA, dizziness, lower extremity edema, increases
digoxin and quinidine levels

Nursing interventions:
◦ Do not crush or chew extended release tablets
◦ Use with caution with other CV agents: digoxin,
beta adrenergic blockers
◦ Monitor for partial or complete heart block, heart
failure

Adenosine (Adenocard)

Digoxin (Lanoxin)

Ibutilide ( Corvert)

Action/Use:
◦ Strong depressant effect on SA and AV nodesslowing conduction
◦ Treatment of paroxysmal supraventricular
tachycardia (PST)
◦ Physiologic roles: energy transfer, prostoglandin
release, inhibits platelet aggregation, coronary
vasodilation, suppresses heart rate

S/E
◦ Flushing, SOB, chest pressure, nausea, HA,
dizziness, peripheral edema, anxiety
◦ Half life is 10 seconds—s/e are not lasting


Give meds on scheduled time
Assess 6 cardinal signs of CV disease
◦ Chest pain, dyspnea, edema, fatigue, syncope,
palpitations (C-D-E-F-S-P)


Lab tests: CV markers (enzymes)
Physical assessment of client: include EKG
readings




Be prepared for emergency care
O2 as needed
Assist with ADLs
Client education
◦ Lifestyle
◦ Medications
◦ Report s/e and adverse effects

Also called ‘idiopathic’

‘essentially’ no known cause

Cardiac output
◦ Increase cardiac output=increased BP

Peripheral vascular resistance (PVR)
◦ Lumen inside vessels will constrict and dilate which
determines PVR


Total Blood volume
(see diagram in Adams)

Carbonic anhydrase inhibitors
◦ Rarely used for hypertension



Thiazides
Loop diuretics
Potassium sparing
◦ Used in combination therapy with thiazide or loop
diuretic



Deplete blood volume
Help excrete sodium
Dilate peripheral aterioles
◦ Specific action unknown

Often used in combination
◦ Potentiates activity of other antihypertensives

Cheap and effective

Thiazides:
◦ Most effective if creatinine clearance >30
◦ Most commonly used: Hydrochlorothiazide

Loop diuretics
◦ Used when creatinine clearance <30
◦ Most commonly used Furosemide (Lasix)

Potassium sparing
◦ Contraindicated with renal disease, pregnancy, gout
or kidney stones
◦ Nursing interventions:
 Monitor labs (WBC decrease, liver and kidney)
 Client education
◦ Most commonly used: Spirolactone (aldactone)
 S/E: gynecomastia, testicular atrophy, hirsutism
Beta-adrenergic blockers
Angiotensin converting enzyme (ACE)
inhibitors
Calcium channel blockers

Action/use:

Propranolol (Inderol)
◦ Inhibit cardiac response to sympathetic nerve
stimulation (block the beta receptors)
 Decreases BP by decreasing cardiac output and heart
rate
 Drugs of choice for Stage 1 & 2 hypertension
◦ Clinical advantages:
 Minimal postural or exercise hypotension
 No effect on sexual function
 Minimal slowing of CNS

S/E/contraindications:
◦ Bradycardia, peripheral vascular resistance, bronchospasm,
wheezing, heart failure, hypoglycemia
 Dose related
◦ Avoid use in clients w asthma, type 1 diabetes, heart
failure, peripheral vascular resistance disease

Nursing implications:
◦ Give lowest dose giving desired effect
◦ Needs days-weeks to get optimal effect
◦ Do not d/c suddenly

Action/use
◦ Prevent angiotensin I converting to angiotensin II =no
vasoconstriction, no aldosterone secretion, no sodium
retention
◦ Preserve cardiac output, increase renal blood flow; use with
diuretic
◦ Does not aggrevate asthma, COPD, diabetes, gout, or
cholesterol levels

S/E:
◦ Nausea, fatigue, HA, diarrhea, orthostatic hypotention:
REPORT: swelling of face, eyes, lips, tongue and SOB

Action:
◦ Binds to angiotensin II receptor sites=no
vasoconstriction
◦ Does not affect bradykinin=no chronic cough
◦ As effective as ACE inhibitors
◦ Need to add diuretic with African-American
population

Action/uses:
◦ Inhibits calcium movement across cell membrane:
reduces arrhythmias, slows rate of contraction of
heart, relaxes smooth muscle of vessels.
◦ Antihypertensive, antianginal, alternative to beta
blockers
◦ Effective in African Americans

S/E:
◦ Hypotension and syncope
◦ Edema


Diltiazem (Cardizem)
Nifedipine (Procardia)

Action/Use:
◦ Aterial and venous vasodilation=reduced PVR
◦ Does not reduce cardiac output, does not cause produce
reflex tachycardia, reduces HDL, increases HDL
◦ Additive effect with beta blockers and diuretics to decrease
BP
◦ Stage 1-3 hypertensions
◦ Helpful in BPH

S/E:
◦ Drowsiness, HA, dizziness, weakness, lethargy
(these are self limiting)
◦ Dizziness, tachycardia, fainting
 Take with food, lie down if s/s

Action:
◦ Stimulates adrenergic receptors in brain stem; reduces
sympathetic outflow from CNS===decreases HR and PVR

Uses/routes:
◦ Combination with other antihypertensive agents; when
other antihypertensive agents do not work.
◦ Patch: action=one wk duration; causes more S/E:sedation,
dry mouth, fatigue, sexual dysfunction

Nursing interventions:
◦ Monitor vitals
◦ I&O
◦ Do not d/c suddenly: causes rebound effect with
rapid rise in BP
 Agitation, restlessness, tremors, HA, nausea, increased
salivation.

Nursing diagnoses:
◦
◦
◦
◦
Excess fluid volume
Risk for fluid volume deficit
Altered urinary elimination
Ineffective health maintenance






Monitor lab values
Observe for changes in LOC
Monitor for hydration
I/O; daily wt, diet monitor
Monitor caffeine and alcohol intake
photosensitivity