Adrenergic Agonists & Antagonists (Ch. 14) Flashcards
Phenylephrine
- acts on which receptor
- its goal
- dose
- duration
(agonist) acts on alpha 1. high doses can act on alpha 2 and beta goal: increase SVR and BP dose: 10mg/ml diluted in 100mcg/ml NS duration: 15min *reflex bradycardia can decrease C.O. *preferred for neuraxial anesthesia
clonidine
- acts on which receptor
- half-life
- effects of drug
- side effects
(agonist)
acts on Alpha 2 receptors
-sympatholytic, antihypertensive and negative chronotropic effects
-12-24hrs half-life
- sedative and anxiolyxis properties
-side effects: bradycardia, hypotension, sedation, dry mouth, resp depression
dexmedetomdine (precedex)
- acts on which receptor
- half-life
- concentration
agonist
acts on alpha 2.
2-3hrs half-life
-100mcg/ml
Epinephrine
effects on: b1, b2, a1
-complications
b1: increases BP, C.O., O2 demand, HR
b2: bronchial relaxation
a2: decreases splanchnic perfusion, renal perfusion, increases coronary perfusion by increasing atrial pressures
- complications: coronay ischemia, cerebral hemorrhage, ventricular arrhythmias
Ephedrine
- type of drug
- concentraton
- comparison w/ epinephrine
- noncathecholamine sympathomimetic (vasopressor use)
- 50mg/ml
- longer duration, less potent, direct and indirect action
- CNS effect increasing MAC
- contains anti-emetic properties
Norepinephrine
- what receptors and effects
- how is an increase in C.O. prevented
- complication
-alpha 1 with little b2: intense vasoconstriction
-b1: increasing contractility + increasing SVR = increasing BP
reflex bradycardia and increased afterload
*tissue necrosis at IV site
Dopamine (DA)
- type of drug
- doses and their effects
nonselective direct and indirect adrenergic and dopaminergic agonist
- low doses(0.5-3mcg/ml)
- D1: diuresis
- mod doses (3-10mcg/ml)
- increase contractility, HR, BP, C.O.
- high doses (10-20mcg/ml)
- alpha 1 stimulated: increasing SVR, decreasing renal blood flow
Dobutamine
-effects on specific receptors
b1: increase contractility and C.O.
b2: decreases SVR, LV f pressures, increases coronary blood flow
Labetolol (Trandate)
- which receptors
- effects
- peak effect
the only alpha and beta blocker A1, B1, B2 decreases HR, C.O., BP, SVR no reflex tachycardia peak effect: <5min
what’s ISA
Intrinsic Sympathomimetic Activity.
Esmolol (brevibloc) concentration which receptor effects avoid w/ what pts half-life elimination
Beta 1 block
ultrashort acting
concentration: 10mg/ml
- decrease HR
-slightly decrease BP
-controls ventricle rate in Afib and Flutter
- high doses inhibits B2 receptors
-avoid pts w/: sinus bradycardia, heartblock > 1st degree, cardiogenic shock, overt HF
distribution half life: 2min
elimination: redistribution, hydrolysis by blood cell!
elimination half life: 6min
Metoprolol (Lopressor)
receptor
dose
B1 antagonist
has no ISA
2-5mg increments Q2-5min
titrated to BP and HR
Propanolol (inderal)
receptors
effects (name 6)
side effects
b1 and b2 blockers 1.decreases BP 2.decreases heart activity 3.\/ HR 4.\/ C.O 5.\/ heart o2 demand 6.slows AV conduction (slows SVT side effects: bronchospasms, CHF, bradycardia, AV block
