Antidysrhythmic and Antihypertensive Agents
description
Transcript of 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, dizzinessimpaired 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, non-productive 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 nodes-
slowing 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:◦ 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
Propranolol (Inderol)
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