Adrenergic Stimulants Flashcards
NE released from?
Stimulates?
nerves
α and β1 receptors
Epinephrine released from?
Stimulates?
adrenal medulla (into circulation)
α and β receptors
NE made how?
Tyrosine into terminal ->
+ tyrosine hydroxylase = L-DOPA ->
Dopamine -> NE
EpiNE made how?
from NE in adrenal medulla
What releases NE from terminal?
amphetamine
tyramine
What inhibits NE from reuptake?
cocaine
antidepressants
NE metabolized by what on reuptake?
MOA (Monoamine oxidase),
COMT
Adrenergic Stim constricts bv to?
What receptors?
skin, kidney, mucous membranes
α1
Adrenergic Stim relaxes bv to?
What receptors?
skeletal mm
β2
Adrenergic Stim of M receptors does what?
↑ saliva and sweat glands
Adrenergic Stim of β2 receptors does what?
relax gut wall and bronchiloes
relax bv to skeletal mm
Adrenergic Stim of β receptors does what?
excite cardiac
glycogenolysis, lipolysis
modulate insuin and renin
Adrenergic Stim of CNS does what?
respiratory stim
wakefulness
↓ appetite
Adrenergic Stim of α2 receptors does what?
inhibit transmitter release
Action of Direct-acting drugs on noradrenergic (NE) terminals?
directly stim α and β receptors
Actions of Indirect-acting drugs on noradrenergic terminals? (3)
↑ release of NE (tyramine) inhibit reuptake (cocaine) inhibit catabolism (MAO inhibitor)
Denervation (depletion of NE) in Noradrenergic terminal has what effect on indirect-acting drugs?
What drug denerves NE terminals?
stops effect
Resperine
Denervation (depletion of NE) in Noradrenergic terminal has what effect on direct-acting drugs?
none or enhance effect
α Receptors respond to what neurotrans?
Epi and NE
α1 Receptors are excitatory or inhibitory?
Route of action?
excitatory
IP3 -> ↑ Ca2+ -> DAG -> activates PKC
α1 Receptors agonist?
Causes?
Phenylephrine
Vasoconstriction, ↑ vascular resistance Vasoconstriction nasal mucosa (↓ congestion) Dilate pupils Contract genitourinary (continence) Stim Pilomotor (hair erection) Glycogenolysis/Glucogenesis
α2 Receptors are excitatory or inhibitory?
Route of action?
inhibitory: (U) presynap where ↓ neurotrans release
↓ adenylyl cyclase -> ↓ cAMP
α2 Receptors agonist?
Causes?
Clonidine
inhibit NE release -> ↓ BP
inhibit ACh release ->: ↓ intestinal tone/secretions, Platelet aggregation, Vasoconstrict coronary, renal, mucosal, skin, ↓ insulin secretion
Affinity of EpiNE, NE, and Isoproterenol on α Receptors?
EpiNE = NE»_space; Iso
Affinity of EpiNE, NE, and Isoproterenol on β Receptors?
Iso ++ for all
Epi = NE for β1
Epi ++, NE - - for β2
NE»_space; Epi for β3
Route of Action for β Receptors?
activate adenylyl cyclase -> ↑ cAMP
β1 Receptor agonist?
Causes?
Dobutamine
↑ rate/force on heart contraction
↑ AV conduction velocity/automaticity
↑ renin secretion by kidney
β2 Receptor agonist?
Causes?
Albuterol
weaker cardiac effects Relax resp, uterine, GI smooth mm Relax BV to skeletal mm Promote K+ uptake by skeletal mm ↑ glycogenolysis/glucogenesis
β3 Receptor agonist?
Causes?
none
lipolysis in fat cells
NE doesn’t effect lungs, why?
mostly β2 receptors, has no affinity for them
Isoproterenol doesn’t effect most BV why?
mostly α receptors, no affinity
Dopamine (DA) Receptors important to? (3)
brain
renal and splanchinic vasculature
D1 receptors route of action?
Causes?
stim adenylyl cyclase
dilate renal BV
D2 receptors route of action?
Causes?
inhibit adenylyl cyclase ->
open K+ channels ->
↓ Ca2+ infulx
inhibits release of transmitters from terminal
Sympathomimetic drugs do?
Effect depends on? (3)
mimic effects of neurotransmitters
proportion of α β activity drug possesses,
distribution of α β receptors in tissue,
reflex responses
Atherosclerosis affects α receptors and baroreceptors how?
↑ effects of α receptors
↓ effects of baro
NE (Levophed) affects what receptors?
⍺ and β1
minor β2
(⍺ = β1»_space; β2)
Levophed administered?
Duration?
IV
very short (rapid metabolism)
Levophed primary effect?
⍺ -> vasoconstriction ->
↑ both S and D blood pressure
β1 -> ↑ HR but baroreceptors will override
Levophed effects on blood flow?
CO?
↓ flow to kidney, spleen, liver
no Δ
Levophed side effect?
vasoconstrict injection site -> necrosis
Levophed primarily used to?
reverse hypotension
Administration of Atropine before Levophed results in?
block vagal reflex of baroreceptors
= HR ↑
EpiNE (Adrenaline) effects what receptors?
⍺, β1, β2
Adrenaline administered?
Duration?
injection
short
Adrenaline effect depends on?
dose
Adrenaline effects on ⍺?
vasoconstriction -> SBP
(initially both BP, then DBP drops due to β2)
↓ insulin secretion
Adrenaline effects on β1?
↑ HR and contraction force
(inotropic and chronotropic)
↑ renin secretion
Adrenaline effects on β2?
dilate BV to skeletal mm ->
↓ DBP (*overrides ⍺ )
↑ glycogenolysis (↑ blood glucose)
bronchodilation
Inotrpoic means?
affects contractility
Chronotropic means?
affects rate/timing
Adrenaline effects on β3?
↑ lipolysis in fat cells = ↑ free fatty acid
Overall result of Adrenaline?
↑ systolic pressure, ↑ HR
little Δ in mean pressure
↑ blood glucose
bromchodilation
Adrenaline low/slow dose results in?
mainly β2 stim (vasodilation):
↑ HR, contractility, coronary blood flow = ↑ CO and O2 consumption
constricted BF to skin, musoca, kidney = ↑ SBP/DBP
Adrenaline high/rapid dose results in?
mainly ⍺ stim (vasoconstriction):
↑↑ SBP/DBP
Primary use of Adrenaline (EpiNE)? (5)
1) anaphylactic shock
2) cardiac arrest/complete heart block
3) ↓ diffusion of local anesthesia (vasoconstr)
4) glaucoma (↑ removal, ↓ production aqueous humor)
5) severe asthma (bronchodil)
Adrenaline side-effects? (6)
tremor throbbing HA ↑↑ BP/hypertension (if β-block) tachycardia angina cerebral hemorrhage
Ephedrine (Ephedra) administered?
Duration?
oral
long
Ephedra acts on what receptors?
⍺ and β (similar to Adrenaline)
Main effects of Ephedra?
bronchodilation
CNS stim
high BP and stroke
Overall effects of ⍺ Agonists?
vasoconstriction -> ↑ peripheral vasc resistance
↑ BP -> ↓ HR (reflex)
Phenylephrine affects what receptors?
Neofrin, Neo-Synephrine
⍺1
Neofrin/Syn effects on ⍺1 receptors?
typical ⍺ Agonist +
vasoconstriction of nasal and up resp bv
Neofrin/Syn used to tx? (3)
1) decongestant
2) pupil dilation for eye exam
3) hypotensive emergency
Neofrin/Syn side-effects?
rebound congestion
caution for HTN pts (↑ HTN)
Methoxamine (Vasoxyl) similar to?
Phenylephrine
use IV for hypotension
Pseudophedrine (Sudafed) affects what receptors?
⍺
Pseudophedrine effects on ⍺ receptors?
Side-effects?
similar to Phenylephrine,
more effective orally than Pheny
caution for HTN
Xylometazoline/Oxymetazoline affect what receptors?
Otrivin/Afrin
direct ⍺ agonists
Xylometazoline/Oxymetazoline administered?
Side-effects?
topically
rebound congestion from receptor down-regulation
Tetrahydrozoline/Naphazoline affect what receptors?
(Visine)
How?
⍺
vasoconstriction
Tetrahydrozoline/Naphazoline contraindicated for?
narrow-angle glaucoma,
HTN
Clonadine (Catapres) affects what receptors?
⍺2
Clonadine effects on ⍺2?
stim ⍺2 in CNS presyn terminal ->
↓ NE release (↓ SNS) ->
↓ BP
Clonadine used to tx?
HTN,
hot flashes,
withdrawal/cravings,
pre-anesthesia (↓ amount needed)
Clonadine administered?
oral
transdermal patch
Clonadine side-effects?
dry mouth, sedation, erect dysfxn
severe HTN if abruptly stopped
Methyldopa (Aldomet) affects what receptors?
Effects?
⍺2
similar to Clonadine
Apraclonidine (Iopidine) affects what receptors?
Effects?
⍺2
↓ aqueous humor -> ↓ IO pressure
Isoproterenol (Isuprel) affects what receptors?
β»_space; ⍺
Isoproterenol effects on β receptors?
vasodilation of skeletal mm and renal/mesenteric vascular beds
↓ BP -> reflex ↑ HR
Isoproterenol used to tx?
emergency cardiac arrest/complete heart block
Isoproterenol side-effects?
tachycardia, palp, arrhyth
Dobutamine (Dobuterex) affects what receptors?
β1
Dobutamine effects on β1?
inotropic (↑ CO/contractility)
Dobutamine used for? (3)
stress tests
cardiac shock
CHF
Dobutamine side-effects?
HTN pt: ↑ HR and BP
Albuterol (Ventolin) affects what receptors?
β2
Albuterol used to tx?
asthma
Albuterol side-effects?
tachycardia
mm tremors
HA
Dopamine (Intropin) affects what receptors?
D1 in renal vascular beds
Dopamine effects on D1?
Used to tx?
vasodilation -> ↑ renal BF -> ↑ filtration/Na+ excretion
cardiac shock
High [Dopamine] affects what other receptors?
β1, ⍺1 and adrenergic NE release
Dopamine side-effects? (6)
N/V tachycardia angina arrhyth HA peripheral vasoconstriction
Fenoldopam (Corlopam) affects what receptors?
D1
Fenoldopam effects on D1?
Used to tx?
dilation of vascular beds ->
↓ BP
severe HTN
Amphetamine affects what receptors?
INDIRECT action on adrenergic and DA, esp in brain (CNS)
Amphetamine effects on adrenergic/DA receptors?
CNS?
Peripheral?
release NE/DA
CNS:
↑ euphoria, alertness, motor activity
↓ appetite, need for sleep
Peripheral:
tachycardia, HTN, psychosis,
contracts urinary sphincter
Amphetamine overdose effects?
cerebral hemorr, convulsions, coma
Amphetamine use to tx? (2)
enuresis (bladder control)
ADHD (methyphenidate/Ritalin)
Cocaine affects what receptors?
INDIRECT action on NE/DA terminals
inhibits reuptake
Cocaine effects on NE/DA receptors?
similar to amphetamines
more intense/shorter acting
powerful vasoconstrictor
Cocaine side-effects?
MI, HTN, stroke
psychosis
Cocaine used for?
nasopharyngeal surgery (vasoconst, local anesthesia)
Tyramine affects what receptors?
INDIRECT action on adrenergic terminals
Tyramine effects on NE terminals?
releases NE,
displaces NE in vesicle -> becomes false transmitter (octopamine)
Tyramine found in? (2)
food
tyrosine by-product
Tyramine results in?
tachyphylaxis (↓ response from prolonged exposure)
Tyramine contraindication?
MAO inhibitors
stop MAO from metabolizing tyramine =
massive NE release =
severe HTN