Adrenergic drugs for CV dysfunction Flashcards
agonists
Epi NE Iso Dobutamine Dopamine Fendoldopam Clonidien Methyldopa
Epi
alpha and beta
NE
alpha and Beta 1, 3
Iso
Beta
Dobutamine
beta 1
Dopamine
D1>beta1>alpha1
fendolopam
D1
Clonidine
alpha2
methyldopa
alpha 2
alpha antagonists
prazosin- alpha 1
phentolamine- alpha 1 and 2
nonselective beta antagonists
propanolol nadolol timolol pindolol carteolol sotalol esmolol (short acting)
cadioselective beta blockers
atenolol
acebutolol
metoprolol
third generation beta blockers
labetalol
carvedilol
betaxolol
carteolol
Epi B1 effects on heart
primary effects positive inotropy and chronotropy increased work of heart and increased O2 demand shortens AP and refractor period decreases grade of AV block
supraventricular arrhythmias
apt to occur w/combo of Wpi and cholinergic stimulation
treat w/beta blocker
Epi B2 effects on heart
B2 may play important role in remodeling of heart tissue that occurs in CHF
Epi alpha 1 effects on heart
prolings refractory period and strengthens myocardial contractions
low dose epi on vasculature
primarily beta 2 vasodilation
high does epi on vasculature
primarily alpha 1 vasoconstriction
epi and cutaneous blood flow
markedly decreased
decreased flow to hand and feet
epi and renal flow
induce alpha mediated vasoconstriction reducing renal blood flow -> increases RAAS
epi and coronary blood flow
increased, but may not increase enough to meet increased demand brought on by Epi
cardiac arrest uses of Epi
- during CPR for persistent or recurrent VT/VF after 1-2 cycles of defibrillation and CPR
- during CPR for PEA
- following CPR and TCP for asystole
- to treat bradycardia w/serious signs and symptoms (combine w/atropine and dopamine)
other uses of Epi
hypersensitivity rxns (anaphylaxis) prolongation of action of local anestetic (vasoconstriction) topical hemostatic agent on bleeding surfaces nebulizer -> pediatric asthma
NE
full agonist at all receptors, but has low affinity for B2
CV effects of NE
- systolic, diastolic, and pulse pressure increased
- CO unchanged or decreased
- TPR increased
- compensatory vagal reflex slows heat
- SV increased
uses of NE
- vasoconstrictor to raise or support BP under certain IC condtions
- in shock level of circulating catecholamines already usually high and NE may further decrease perfusion to tissues, especially kidney
dopmaine
agaonist at all DRs
at high concentrations will activate beta 1 at heart and at even higher concentrations will activate alpha 1 -> generalized vasoconstriction
D1Rs mediate vasodilation in renal and mesenteric vascular bedsq
CV effects of low concentrations DA
D1
vasodilation, increased GFR, RBF, and Na excretion
useful in low CO states such as shock or CHF
CV effects of moderate does of DA
-positive ionotropic effect via B1Rs
-causes release of NE from nerve terminals
-increases CO which can be used in treatment of cardiogenic shock
-increased systolic BP and pulse pressure, no effect or slight increase of diastolic BP
TPR unchanged
high concentrations of DA
activates vascular A1 -> more generalized vasoconstricton
counterproductive and undesirable in shock
fendolapam
D1
IV infusion pump for severe HTN
dilates coronaries, afferent and efferent arterioles in kindey and mesenteric aa
+ isomer dobutamine
potent alpha 1 antagonist
10x more potent beta agonist than - isomer
- isomer dobutamine
potent alpha 1 agonist
weaker beta agonist than + isomer
racemic dobutamine
beta 1 like
dobutamine on CV
relatively greater inotropic then chronotropic effects when compared to iso
due to unchanged TPR
therapeutic uses of dobutamine
short term treatment of caRdiac decompenstation after cardiac surgery or CHF or AMI
infusion w/echocardiogram useful in noninvasice assessmetn of coronary artery disease
iso
potent non selective beta agonist
lowers TPR, primarily in skeletal m via beta 2
diastolic pressure falls
systolic maintained or rise
MAP typically falls
CO increased
may cause palpitations, sinus tachycardia, arrhythmias
uses of iso
stimulate heart rate in patients w/bradycardia or heart block, usually just before placement of pacemaker or in patients w/torsades de pointes
clondidine
prototypic alpha2 agonist
initially used as vasoconstricting nasodecongestant
bind in CV control centers of CNS suppressing sympathetics
methyldopa
false neurotransmitter
agonist on brain alpha 2 receptors
preferred treatment for HTN in pregnancy
effect of clonidine
changes in BP and HR
-IV infusion -> acute rise in BP due to activation of postsynpatic alpha 2 in peripheral smooth m vasculature
affinity of these Rs is strong, but clonidine is only a partial agonist
-transient vasoconstriction followed by more prolonged hypotensie response due do decreased sympathetics
-HTN follows parenteral administration generally not seen PO,
uses of clonadine
treatment of HTN off label for -diarrhea due to autonomic neuropathy in DI -preoperative sedation -patch for postmenopausal hot flashes -differential diagnosis of pheocrhomocytoma -ADHS -tourettes -restless leg syndrome
non-selective alpha blockers
phenoxybenzamine (irreversible)
phentolamine
alpha 1 selective blockers
prazosin doxazosin terazosin tamsulosin (BPH) ALFUZOSIN (BPH) third line for treatment of essential HTN
labetolol and carvediol
block beta and alpha
carteolol
block alpha and beta, except agonist at beta 2
nebivolol and carteolol
activate NO production
carvediol
antioxidant activity
tilisolol
K channel opening
beta blocker CV effects
slow sinus rate, decrease spontaneous rate of ectopic pacemakers, slow conduction in atria and AV node, increase functional refractory period of AV node
beta blockers and HTN
blocks renin release which is usually mediated by beta 1
long term use of beta blockers will lead to fall in TPR, not understood
CV adverse effects of beta blockers
- may induce CHF in susceptible patients
- bradycardia normal, however can be threatening in partial or complete AV conduction defects
- abrupt discontinuation
- decreased exercise treatment
uses of beta blockers
HTN angina acute coronary syndromes CHF supraventricular and ventricular arrythmias
CHF
certain beta blockers are highly effective treatments for all grades of heart failure
carvediol, metoprolol, xamterol
usually takes weeks-months to see benefit (except carvediol)
MI
beta blockers in early phases, but must be continued long term
hypertrophic obstructive cardiomyopathy
beta blockers, specifically propranolol
relieves angina, palpitations, and syncope
actue dissecting aortic aneurysm
reductionin force of contraction and rate
chronic treatment w/propranolol in marfans as prevention
hyperthyroidism
beta blockers useful
nadolol
long-acting antagonsit w/equal affinity for beta 1 and 2
relatively long half life
used for HTN and angina, magraine porphylaxis, parkinsonian tremors, and variceal bleeding in portal HTN
metoprolol
cardioselective
extended release available
essential HTN, angina, tachycardia, heart failure, vasovagal syncope, hyperthyroidism, and for migraine prophylaxis
atenolol
cadioselective
hydrophilic -> penetrates CNS to a limited extent
half life longer then metoprolol
HTN, coronary heart disease, arrhythmias, angian, post MI, graves disease
atenolol combos
with diuretic in elderly w/isolated systolic HTN
esmolol
cardioselective rapid onset, short acting IV surgery to prevent or treat tachycardia supraventricular tachycardia striking hypotensive effects
labetalol mixture properties
selective blockade of alpha, beta 1, beta 2
partial agonist of beta 2
inhibits neuronal uptake of NE
blocks beta 5-10x more then alpha
labetaolol effects
fall in BP
HR maintained or slightly reduces
CO maintained
can be used in pregnancy induced HTN crisis
carvediolol
blocks beta 1,2 and alpha 1, but also has antioxidant and anti-inflammatory effects
HTN, CHF, left ventricular dysfunction post MI
