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