Adrenergic Receptor Agonists and Antagonists Used to Treat Cardiovascular Disease Flashcards
Epinephrine Agonist
(a1, a2, b1, b2, b3)
pressor agents do what?
support BP
Norepinephrine Agonist
(a1, a2, b1, b3)
Isoproterenol Agonist
(b1, b2, b3)
Dobutamine Agonist
b1
Fenoldopam Agonist
D1
Clonidine Agonist
a1
Methyldopa Agonist
a2
Prazosin Antagonist
a1
Phentolamine Antagonist
a1,a2
Phenylephrine agonist
Alpha receptors
Beta Receptor Antagonists
Nonselective
Propranolol
Nadolol
Timolol
- Pindolol
- Carteolol
Sotalol
*= Intrinsic Sympathomimetic Activity (ISA)
b1 b2 and b3
Beta Receptor Antagonists
Cardioselective
Atenolol
*Acebutolol
Metoprolol
b1 over b2
advantages to pts with diabetes and asthma
Beta Receptor Antagonists
Third Generation
Labetalol
Carvedilol
Betaxolol
Carteolol
tratment of mi and chf
Para Neurotransmitters
Pre- Ach N
Post- Ach M
Sympathetic sweat glands Neurotransmitters
Pre- Ach N
Post- Ach M
Sympathetic Cardiac and smooth muscle gland cells and nerve terminals neurotransmitters
Pre- Ach N
Post- NE a and b
Sympathetic Renal vascular smooth muscle neurotransmitters
Pre- Ach N
Post- D1
Somatic skeletal muscle neurotransmitters
Pre- Ach N
Dopamine Effects
CNS
D1, D2, D3, D4, D5
Essential neurotransmitter in many different neural circuits
Dopamine Effects
Renal Afferent Blood Vessels
D1–Dilation
Increase blood flow to kidney
need in shock so you can increase blood flow to kidney
Dopamine Effects
Nerve Endings
D2–Modulate neurotransmitter release
Baroreceptor Reflex Control of Heart Rate and Blood Pressure
b1
muscarinic
a1
b2
b1 - stimulation of heart rate & force
muscarinic - decrease in heart rate
a1 - vasoconstriction
b2 - vasodilation
a1-Adrenergic Agonists
a1-adrenergic agonists are Pressor Agents
Phenylephrine (Neosynephrine) Prototype
Over-the–counter nasal decongestant
Midodrine (Pro Amatine)
oral –pts w/ autonomic insufficiency
Mixed Acting Alpha agonists
Metaraminol (Aramine)
have direct alpha receptor agonist properties and release norepi from nerve ending
pressor agents do what?
increase BP
Phenylephrine (prototype alpha agonist)
Effects:
vasoconstriction
increase peripheral resistance; increase BP
increased blood pressure causes reflex bradycardia (blocked by atropine)
Phenylephrine (prototype alpha agonist)
Uses
to maintain BP in hypotensive states
spinal anesthesia
paroxysmal atrial tachycardia
induces baroreceptor reflex slowing of rate
Nasal decongestant –over the counter cough and cold medications
Phenylephrine (prototype alpha agonist)
can also be used through iv
for pressor agent bc of its alpha effects
Dopamine (Intropin)
Important neurotransmitter in CNS
CNS receptors: D1, D2, D3, D4, D5
Peripheral receptors: D1, b1, a1
Dopamine (Intropin)
Pharmacological effects
blood vessels: vasodilates renal, coronary, & mesenteric vascular beds (D1 receptors)
increase blood flow to kidney
heart: mild increase in rate & force (partial agonist b1 and increases release of NE)
blood vessels: high doses cause vasoconstriction & increased BP (a1)-in the situation of “shock”, this is an undesirable effect bec. Decrease tissue perfusion
Dopamine (Intropin)
Dose Dependancy
at low levels d1 is kicked in for renal
hihger levels with b1 receptor in heart
at really ighg it will cause vaso from alpha 1
Dopamine (Intropin)
Clinical Uses
Shock; cardiogenic shock, unstable CHF
Increases cardiac output and enhances perfusion of kidney
Must monitor BP carefully because higher infusion rate or dose causes vasoconstriction and decreased tissue perfusion
Sometimes used in manage acute crisis in chronic CHF
Dobutamine (Dobutrex)
b1-selective agonist
actually complicated b1 agonist, a1 agonist/antagonist
inotropic agent to increase co
Dobutamine (Dobutrex)
Clinically mostly b1 effects
positive inotropic & some increase in rate
Cardiac output increases
little vascular effect
Dobutamine (Dobutrex)
Clinical uses
Clinical Use: cardiogenic shock, MI, CHF
short term treatemnt to give th heart a boost
Dobutamine (Dobutrex)
AE
may increase size of infarct
potential arrhythmias
Increases the work/O2
requirement
after crisis it can exacerbate the ischemia
a1-selective Receptor Blockers
Clinical Use
2ndor 3rdline treatment of essential hypertension; added to other agents from different class
a1-selective Receptor Blockers
Effects
Effects
↓PVR, ↓venous return, ↓ preload
Usually do not ↑ heart rate or cardiac output
Do not ↑ NE release (no a2 block) (good bc you arent limiting ne release)
Favorable effects on lipids
↓LDL & triglycerides; ↑HDL
a1-selective Receptor Blockers
AE
Can cause marked postural hypotension & syncope, orthostatic hypotension, especially with initial doses
Usually given at bedtime to minimize hypotensive effects
a1-selective Receptor Blockers
Drug list
Prazosin(Minipress)
Terazosin(Hytrin)
Doxazosin(Cardura)
Prazosin(Minipress)
100x a1 selective
Short t1/2, BID or TID dosing, titrate upward
Prototype?