L6, L8- Adrenergic Drug Overview Flashcards
list some disorders that are treated with adrenergic agonists or antagonists
- HTN
- HF, angina, arrhythmias
- asthma
- migraine
- anaphylactic reactions
describe the effect of epinephrine at low and high doses in skeletal muscle vasculature
Low: β2 more sensitive than α1, therefore physiological concentrations of epinephrine => vasodilation
High: α1/β2 activated, α1 predominates => vasoconstriction
describe the effects of epinephrine at low and high concentrations in terms of adrenergic activation
Low: mainly β1/β2 receptors are activated
High: α1 effects are more pronounced
list the general effects of epinephrine
- inc HR + contractile force => inc CO (inc myocardium O2 demand) (β1)
- inc renin release (β1)
-skin and viscera arterial vasoconstriction (α1)
- skeletal muscle BVs vasodilate (β2)
- bronchodilation (β2)
- inc liver glycogenolysis, inc α-cell glucagon release (β2)
-inc lipolysis (β1/β2)
describe the effects of epinephrine on BP at high doses (given IV)
Net inc in MAP:
- inc ventricular contraction (β1)
- inc HR (β1): may be opposed by baroreceptor reflex
- vasoconstriction (α1)
describe the effects of epinephrine on BP at low doses (given IV)
No net inc in MAP:
-inc ventricular contraction + inc HR (β1) => inc systolic pressure
-dec peripheral resistance, vasodilation (β2 more sensitive than α1) => dec diastolic pressure
[no change in MAP = no baroreceptor reflex]
describe the cardiovascular effects of NE
(Note- very little if any β2 activation)
Inc peripheral vascular resistance, SP, DP –> inc MAP + dec HR:
-peripheral vasoconstriction (α1)
-inc cardiac contractility (β1- CO is unchanged/decreased)
-inc MAP –> bradycardia via baroreceptor reflex
describe baroreceptor reflex in response to vasoconstriction / increased BP
- carotid sinus –> inc PSNS activity, dec SNS activity
- inc PSNS + dec SNS => dec HR
- dec SNS => dec cardiac force of contraction
describe baroreceptor reflex in response to vasodilation / decreased BP
- carotid sinus –> inc SNS activity, dec PSNS activity
- inc SNS + dec PSNS => inc HR
- inc SNS => inc cardiac force of contraction
the main cardiovascular effect of NE proceeding atropine administration is….
tachycardia
list in order of highest affinity the receptors DA binds to (in SNS)
D1 > β1 > α1
describe the cardiovascular effects of low dose dopamine
Mainly D1 in renal and other vascular beds are activated:
- vasodilation
- inc GFR, renal blood flow, Na excretion
describe the cardiovascular effects of intermediate dose dopamine
- more β1 receptors activated in heart inc CO (very little for β2)
- inc NE release from nerve terminals –> contributes to cardiac effects
- inc systolic BP, no change in diastolic => inc MAP, PVR unchanged
describe the cardiovascular effects of high dose dopamine
-more α1 receptors activated in vasculature => vasoconstriction –> inc BP
-TPR may be increased
(Note- these are the therapeutic or clinical doses used)
describe the effects of isoproterenol
(β agonist)
- β1: inc HR (potentiated by baroreceptor reflex), contractility, CO
- β2: skeletal muscle arteriole dilation –> dec PVR + bronchodilation
- dec diastolic, inc systolic pressure => dec MAP
dobutamine is a (1) type adrenergic drug that exhibits (2) type effect on the heart with (3) effects as the end result. It also has (4) effects on vasculature
1- β1 agonist
2- inotropic (mild chronotropic)
3- mild inc in HR and PVR
4- mild vasodilation
list the adverse effects of β2 agonists
- tremor, restlestness, apprehension, anxiety, tachycardia
- less likely in inhalation than with parenteral or oral therapy
describe the cardiovascular effects of phenylephrine
α1 vasoconstriction –> inc PVR –> inc diastolic/systolic BP + MAP => baroreceptor reflex leading to dec HR
clonidine works by activating on (1) receptors which leads to (2) in order to reduce (3); its adverse effects are (4)
1- pre-synaptic α2 receptors
2- reduce SNS outflow
3- reduce BP
4- lethargy, sedation, xerostomia
methyldopa is converted to (1) in order to act on (2) receptors, and results in (3) overall; its adverse effects are (4)
1- α-methylnorepinephrine (within noradrenerigic neurons)
2- central α2 receptors
3- dec BP
4- sedation, impaired mental concentration, xerostomia