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Define positive intotropic agent?
increase force of myocardial contraction
why is inotropic drug used?
heart muscle failure
types of positive inotropic agents?
- cardiac glycoside (digoxin)
- phosphodiesterase inhibitor
Define heart failure?
heart unable to pump blood in sufficient amt from ventricles to meet body metabolic needs
What cardiac glycoside is commonly used? origin? why is it used?
Digoxin comes from foxglove plant and used in heart failure to control ventricle response to A Fib or flutter
cardiac glycoside action?
- increase contractility
- decrease rate of electrical conduction
- prolong refractory period (between SA node/AV node)
- results in decrease HR/improve cardiac efficiency
define chronotropic agent?
changes rate of heartbeat
define dromotropic agent?
change conduction of electrical impulses
drug effect of positive inotropic drug?
increase force/velocity of contraction w/o increase of O2 consumption
drug effect of negative chronotropic drug?
reduce heart rate
drug effect of negative dromotropic drug?
- decrease automaticity at SA node
- decrease AV nodal conduction
drug effects of cardiac glycoside?
- increase stroke volume
- reduction in heart size at diastole
- decrease venous BP / vein engorgement
- promotion of diuresis d/t improve blood circulation
Adverse effect of cardiac glycoside?
- narrow therapeutic window-toxicity
- low potassium levels increase toxicity
- dysrhythmia (brady/tachycardia),
- headache, fatigue, confusion, convulsion
- colored vision/halo vision, flickering lights
- anorexia, nausea, vomit, diarrhea
antidote for digoxin toxicity
digoxin immune Fab
- hypokalemia, hypercalcemia
- cardiac pacemaker
- hepatic dysfunction
- hypothyroid/respiratory/ or renal disease
- advanced age
how do phosphodiesterase inhibitors work?
inhibit enzyme phosphodiesterase giving a positive inotropic response and vasodilation
phosphodiesterase inhibitor drugs?
why are phosphodiesterase used?
- short term management of heart failure
- no response to digoxin, diuretics, and/or vasodilator
phosphodiesterase side effects?
- Inamrionon: thrombocytopenia, dysrhythmia, nausea, hypotension, elevated liver enzyme w/ long term use
- milrinone: dysrhythmia, hypotension, angina, tremor, thromboycytopenia, hypokalemia
what labs should be monitored with phosphodiesterase?
potassium, sodium, magnesium, calcium, renal/liver fxn
when would you hold dose of positive inotropic drug?
- apical pulse < 60 or > 120 bpm
- toxicity (s/s: anorexia, nausea, vomit, diarrhea, blur vision, halo lights, flickering)
why is fiber not advised with positive inotropic drug?
binds with medication
weight gain and positive inotropic drug?
report >2 lb in 1 day or > 5 lb in 1 week
IV inamrinone and glucose?
- do not mix glucose with IV inamrinone
- IV inamrinone soln is true yellow in color
therepeutic effects of Positive inotropic drugs?
- increase urine output
- decrease edema, SOB, dyspnea, crackles, fatigue
- resolve NOC dyspnea
- improve peripheral pulse, skin color, temp
any deviation from normal rhythm of heart
why are antidysrhythmic drug used?
used for tx and prevention of disturbances in cardiac rhythm
define action potential of heart?
change in distribution of ions that cause cardiac cells to become excited. the movement of ions across cells membrane that results in electrical impulse across cardiac cell and leads to contraction of myocardial muscle.
name the common dysrhythmias?
- ectopic foci
- conduction block
define vaughan williams classification?
system used to classify antidysrhythmic drugs based on the drug and how it effects action potential
class I of vaughan williams classification?
- class 1 drug: moricizine - characteristic of all 3 classes and use for life threaten dysrhythnmia .
- membrane stabilizing drug,
- fast sodium channel blocker
- 1a) quinidine, procainamide, disopyramide : block sodium channel, delay repolarization, incrase APD (use for A fib, vent tachycardia)
- 1b) mexiletine, phenytoin, lidocaine: block sodium channel, accelerate repolarization, increase/decrease APD (use for vent dysrhythmia ONLY)
- 1c) flecainide, propafenone: block sodium channel, (use for severe vent dysrhythmia, A fib, supraventricular tachycardia dysrhthymia)
class II vaughan williams classification?
- Drugs: Beta blockers (atenolol, esmolol, metaprolol, propranolol)
- action: they reduce/block SNS stimulation and reduce transmission of impulse in conduction system, depress phase 4 depolarization
class III vaughan williams classification?
- drugs: amiodarone, sotalol, ibutilide
- action: increase APD, prolong repolarization in phase 3
- use: dysrhythmia difficult to treat (life threaten vent. tachycardia or flutter, resist to other drug, sustain vent. tachycardia)
Class IV vaughan williams classification?
- drugs: verapamil, diltiazem
- action: calcium channel blocker that inhibit slow channel pathway, depress phase 4 depolarization, reduce AV node conduction
- use: paroxysmal supraventrical tachycardia, rate control for A fib and flutter
which drugs are unclassified antidysrhythmics?
- Adensosine (adenocard)
action of adenosine(adenocard)?
slow conduction through AV node and convert paroxysmal supraventrical tachycardia to sinus rhythm
How is adenosine administered?
fast IV push (1/2 life < 10 sec)
side effect to adensosine?
asystole for few seconds
side effect to antidysrhythmic drugs?
dysrhymia, nausea, vomit, diarrhea, dizziness, blur vision, headache
antidysrythmic drugs nursing implications?
- baseline I/O, BP, P, cardiac rhythm
- measure serum potassium at start
- assess for contraindication
- monitor for toxicity (SOB, edema, dizziness, syncope, chest pain, GI distress, blur vision)
- if dose missed call doctor
- dont crush/chew medication
- class 1: monitor ECG for QT interval prolong > 50%
- IV infusion w/ pump
- lidocaine soln w/ epinephrine NOT given w/ IV only as local anesthetic
antidysrhythmic drug therapeutic effect?
- decrease BP, decrease edema, fatigue
- regular HR w/o major irregularities
- improved regularity of rhythm and cardiac output
what is angina pectoris?
chest pain brought on when O2 supply and nutrients in blood is insufficient to meet demands of heart
poor blood supply to an organ
define ischemic heart disease?
poor blood supply to heart muscle (atherosclerosis, coronary heart disease)
define myocardial infarction (MI)
necrosis or death of cardiac tissue that is disabling or fatal
types of angina?
- chronic stable /classic / effort
- unstable / preinfarction / crescendo
- vasospastic / prinzmetal's/ variant
drugs used for angina?
- beta blockers
- calcium channel blockers
why is medication given for angina?
- increase blood flow to ischemic heart muscle
- decrease myocardial oxygen demand
- minimize frequency of attacks
- decrease duration/intensity of anginal pain
- improve pt fxn capacity with few side effect
- prevent / delay worst outcome (MI)
avail forms of nitrates?
- chewable tab
- oral tab/capsule
- IV soln
- TD patch
- TL spray
action of nitrates?
vasodilation d/t relaxation of smooth muscle
why are nitrates used?
prevention/tx of angina
rapid acting vs long acting nitrates?
- rapid acting: tx of acute anginal attack, sublingual or IV
- long acting: use for prevention of anginal episodes
- large first pass effect with oral form
- used: symptomatic tx of ischemic heart condition (angina)
- IV form use: BP control perioperative, hypertension, tx of CHF, ischemic pain, pulm edema assoc w/ acute MI, hypertensive emergency
specific drug types of nitrates? and uses?
- isosorbide dinitrate (isordil, sorbitrate)
- isosoride mononitrate (imdur, monoket)
- use: acute relief of angina, prophalaxis that may provoke angina, long term angina
adverse effect of nitrate?
- head ache
- tachycardia, posteral hypotension
tolerance to nitrates?
- long acting forms or with round clock usage
- prevented by allow nitrate free period to allow enzyme pathways to replenish (remove patch after 8 hr and reapply in morn)
beta blocker drug names ?
- atenolol (tenormin)
- metoprolol (lopressor)
- propranolol (inderal)
- nadolol (corgard)
action of beta blocker?
- beta receptor on heart blocked which decreases HR result in decrease myocardial O2 demand /increase O2 delivery to heart
- decrease contractility help to conserve energy/decrease demand
why are beta blockers used?
- cardiac dysrythmia
- cardioprotective effect (after MI)
- migraine headache, tremor, stage fright
beta blocker side effect?
bradycardia, hypotension, 2nd/3rd degree block, heart failure, change in glucose/lipid metabolism, dizziness, depression, lethargy, unusual dream, impotence, wheeze, dyspnea
calcium channel drug names?
- verapamil (calan, isoptin)
- diltiazem (cardizem)
- nifedipine (procardia)
- amlodipine (norvasc)
action of calcium channel blocker?
vasodilation, decrease system vascular resistance, reduce workload of heart all which decrease O2 demand
why use calcium channel blocker?
angina, hypertension, supraventricular tachycardia, coronoary artery spasm, short term manage of A fib and flutter
adverse effect to calcium channel blocker?
hypotension, palpitation, tachy/bradycardia, constipation, nausea, dyspnea
nurse implication for antianginal meds?
- baseline VS include resp pattern/rate
- limit caffiene intake
- report blur vision, fainting, edema, wt gain 2+ /day or 5+/week, HR < 60 bpm , dyspnea
- no alcohol, hot tub, d/t vasodilation/ hypotension or fainting
- postural hypotension so change position slowly
- keep record of angina attacks
- nitroglycerin: no chew/swallow SL form, burn sensation indicates still potent, take PRN at first sign of angina pain, IV form must be given with special non PVC tubing /bags and discard if soln blue/green/dark red
- calcium channel block: constipation common drink extra water and high fiber food
- beta blocker: monitor HR report < 60 bpm. dizziness / fainting report, constipation common, never stop medication abruptly, for long term angina pain
how to take nitroglycerin if angina pain occurs?
- stop activity/ sit or lie down
- take SL tab wait 5 min
- if not releif, take 2nd SL tab
- wait 5 min, if no relief take 3rd SL tab
- after 3 tab/ 15 min: if no relief of chest pain call 911- DO NOT DRIVE SELF TO HOSP
what is blood pressure?
measured by cardiac output (x) systemic vascular resistance
what are the 4 stages of hypertension based on measurement?
- stage 1 hypertension
- stage 2 hypertension
significant changes in BP facts?
- high DBP is no longer considered more danger then high SBP (high SBP assoc w/ heart fail, stroke, renal failure)
- older then age 50: SBP more important risk for cardiovascular disease then DBP
- prehypertension: BP no longer considered high normal and require lifestyle change
- thiazide diuretic initial drug therapy (alone or w/ others)
- mild/moderate/severe have been dropped
culteral consideration with antihypertensive drugs?
- beta blocker/ ACE inhibitor more effective in caucasian vs. african american
- calcium channel block/ diuretic more effective with african american vs caucasion
hypertension classification based on cause?
- unknown cause: known as essential, idiopathic, or primary (90% )
- known cause: secondary hypertension (10%)
role of parasympathetic nervous system vs sympathetic nervous system?
- parasympathetic: stimulate smooth/cardiac muscle and glands
- sympathetic: stimulate heart, blood vessel, skeletal muscle
catagories of hypertensive drugs?
- adrenergic drug
- angiotensisn converting enzyme inhibitor (ACE inhibitor)
- angiotensin II receptor blocker (ARB)
- calcium channel blocvker (CCB)
adrenergic drug names that are peripheral alpha 1 blocker/agonist?
- doxazosin (cardura)
- prazosin (minipress)
- terazosin (hytrin)
- action: block alpha 1 adreneric receptor
- result: decrease BP
adrenergic drug names that are central acting alpha2 receptor agonists?
- clonidine (catapres)
- guanfacine (tenex)
- methyldopa (aldomet) drug of choice for pregnancy
- action: stimulate alpha 2 receptor in brain, NE production is decreased and renin in kidney reduced
- result: lower BP
adrenergic drug names that are beta blockers ?
- action: reducing HR through Beta 1 block, cause reduction of renin secretion, long term causes peripheral vascular resistance
adrenergic drug name that are dual action alpha 1 and alpha B receptor blockers?
- action: reduce HR adn vasodilation
adrenergic drug names for central/peripherally acting neuron blocker?
reserpine (rarely used r/t side effect)
uses for central acting alpha 2 receptor agonist?
- other drugs fail d/t side effect
- dysmenorrhea, menopausal flush, glaucoma
- clonidine: withdrawal symptom in opioid or nicotine dependent
side effect to adrenergic drugs?
dry mouth, sedation, sleepiness, constipation, headache, rash, cardiac disturbances, palpitaion, orthostatic hypotension
action of ACE inhibitor?
block angiotenson converting enzyme which prevents formation of angiotensin II, and prevents breakdown of vasodilation substance (bradykin) and results in decrease vascular resistance / vasodilation which decrease BP
drug names for ACE inhibitor?
- captopril (capoten) - short half life
- enalapril (vasotec)- oral or parenteral form
- lisinopril (prinovil/zestril)- newer drugs, long half life, once daily
ACE inhibitor side effect?
fatigue, head ache, impaired taste, dizziness, mood change, hyperkalemia, dry nonproductive cough, angioedema, first dose hypotensive effect
angiotensin II receptor blocker actions?
angiotension 1 to convert to angiotensin II but block receptors that recieve angiotensin II which blocks vasoconstriction and release of aldosterone
drug names for angiotensin II receptor blockers?
- losartan (cozaar, hyzaar)
- valsartan (diovan)
why use an angiotension II receptor blocker?
- adjunctive drug for tx of HF
- use alone or w/ other drug as diuretic
- use for pt who cant tolerate ACE inhibitor
side effect to angiotensin II receptor blocker?
- URI, head ache, occasional dizziness, unable to sleep, dirrhea, dyspnea, heartburn, nasal congestion, back pain, fatigue, hyperkalemia (less likely)
- NO DRY COUGH
calcium channel blocker action?
- smooth muscle relaxation by blocking binding of calcium to receptors
- prevent muscle contraction
- causing decrease in peripheral smooth muscle tone/ decrease vascular resistance
drug names for calcium channel blocker?
- benzothiazepines: diltiazem (cardizem, dilacor)
- phenylalkamines: verapamil (calan, isoptin)
- dihydrophyridines: amlodipine (norvasc), bepridil (vascor), nicardipine (cardene), nifedipine (procardia), nimodipine (nimotop)
why use calcium channel blocker?
- migraine headache
- raynauds disease
side effect to calcium channel blocker?
hypotension, palpitation, tachycardia, constipation, nausea, rash, flush, edema, dermatitis