E1- Adrenergic Stimulants Flashcards
What type of adrenergic agent acts on presynaptic neuron to increase synthesis, cause release, and inhibit re-uptake?
Indirect acting
What type of adrenergic agent acts on adrenergic receptors on target tissues to mimic sympathetic stimulation?
Direct acting
What type of adrenergic agent stops indirect acting and may enhance direct acting?
Denervation
What is the relative affinity of EPI, NE, and Isoproterenol for both alpha 1 and alpha 2 receptors?
EPI and NE > Isoproterenol
Between alpha, beta, and dopamine, what is the only inhibitory receptor?
Alpha 2
What is the role of of alpha 1 receptors?
Vasoconstriction in skin, kidney, and mucous membranes
What is the role of of alpha 2 receptors?
Presynaptic
Inhibit neurotransmitter release
What is the relative affinity of EPI, NE, and Isoproterenol for beta 1 receptors?
Isoproterenol > EPI and NE
What is the role of beta 1 receptors?
Increase force and rate of contraction of the heart
Increase renin secretion from the kidney
What is the relative affinity of EPI, NE, and Isoproterenol for beta 2 receptors?
Isoproterenol > EPI > NE
What is the role of beta 2 receptors?
Relax bronchioles and gut smooth muscles
Increase glycogenesis
Vasodilate blood vessels supplying skeletal muscles
What is the relative affinity of EPI, NE, and Isoproterenol for beta 3 receptors?
Isoproterenol and NE > EPI
What is the role of beta 3 receptors?
Increase lipolysis
What is the role of D1 receptors?
Vasodilate renal vasculature
What receptors does NE stimulate? With what affinity?
Stimulates alpha and beta receptors
a1 = B1 > B2
What is the affect of NE on a1 and b1 receptors?
a1= Vasconstriction, increase BP
B1= Increase HR
Baroreflex responds and decreases HR, therefore CO is either unchanged or decreased
What the the route of administration of NE?
IV
Very short acting
What is NE used for?
Rarely used to increase BP for severe hypotensive crisis
Are cocaine, tyramine, amphetamine, and MAOIs indirect acting, direct acting, or denervation agents?
Indirect acting agents
If atropine is given prior to NE, what will happen?
The vagal reflex is inhibited, the baroreceptor effect will not occur, and the HR will increase
What receptors does EPI stimulate? With what affinity?
Activates all adrenergic receptors
B1 = B2 > a1
What receptor does low dose EPI stimulate? What affect does this have?
B2 Vasodilate blood vessels supplying skeletal muscle - Decreased DBP - Increased PP - No change in MAP - No baroreflex to slow HR - HR stays increased
What receptor does high dose EPI stimulate? What affect does this have?
a1 overrides B2 Vasoconstriction - Increased DBP - Increased MAP - Baroreflex responds - HR slows
What is EPI used for?
Anaphylactic shock
Decrease diffusion of anesthetics (vasoconstrictor)
Glaucoma
Emergency tx for cardiac arrest and complete heart block
What are contraindications of NE?
Severe vasoconstriction at the infusion site that can lead to necrosis
What are contraindications of EPI?
Pts taking beta-blockers (unopposed alpha effects, so it can lead to severe HTN)
What are side effects of EPI?
Tremor Throbbing HA Increased BP Tachycardia Angina in pts with CAD
What can be used to reverse the effects of EPI?
Alpha blockers
What are the three drugs classified as alpha 1 agonist?
Phenylephrine
Pseudeophedrine
Oxymetazoline
What is Phenylephrine used for?
Hypotensive emergency
Decongestant (vasoconstrict nasal mucosa)
Mydriasis
What are contraindication of Phenylephrin?
Caution in pts with HTN and BPH
What is the main side effect of Phenylephrine?
Rebound decongestion
What drug is similar to Phenylephrine, but more effective?
Pseudeophedrine
What is Oxymetazoline used for?
Decrease redness in the eye
Decongestant
What are contraindications of Oxymetazoline?
Caution in pts with glaucoma and HTN
What are the three drugs classified as alpha 2 agonist?
Clonidine
Methyldopa
Tizanidine
What is Clonidine used for?
Decreases cravings in recovering addicts
Decreases hot flashes
Pre-anesthetic to sedate and dry secretions
What are side effects of Clonidine?
Xerostomia Sedation Erectile dysfunction Sudden withdraw can lead to HTN crisis Avoid getting patch hot, can lead to hypotension
What is Methyldopa used for?
HTN
What are contraindications of Methyldopa?
Not recommended for monotherapy b/c of CNS effects (only used fo refractory HTN pts)
What are side effects of Methyldopa?
Xerostomia Sedation Erectile dysfunction Hemolytic anemia Hepatotoxicity
What drug is recommended to tx HTN in pregnancy?
Methyldopa
What is Tizanidine used for?
Muscle spasticity in neurological conditions
What is the main side effect of Tizanidine?
Asthenia (dose-related effect defined as weakness, fatigue, and/or tiredness)
What is the one drug classified as a non-specific beta agonist?
Isoproterenol
B1 and B2 agonst
What is Isoproterenol used for?
Emergency tx for cardiac arrest and complete heart block
What are side effects of Isoproterenol?
Tachycardia
Palpations
Arrhythmias
What is the one drug classified as a beta1 agonist?
Dobutamine
How is Dobutamine administered?
IV
What is Dobutamine used for?
Increase contractility and output in cardiogenic shock and low output heart failure
Cardiac stress tests if pt cannot exercise
What should you watch out for when giving Dobutamine to a pt with HTN?
BP may increase if given too quickly
What is the one drug classified as a beta2 agonist?
Albuterol
What is Albuterol used for?
Athma
What are side effects of Albuterol?
H/A
Tachycardia
Palpitations
Tremor
What is the one drug classified as a beta3 agonist?
Mirabegron
What is Mirabegron used for?
Overactive bladder (relaxes detrusor muscle to increase bladder capacity)
What are the side effects of Mirabegron?
HTN
Tachycardia
What is the two drug classified as dopamine agonist?
Dopamine
Fenoldopam
What is the effect/use of low dose dopamine?
Renal vasodilation via D1 receptors in the kidey
What is the effect/use of moderate dose dopamine?
Inotropic effect via B1 receptors in the heart
What is the effect/use of high dose dopamine?
Vasocontriction via alpha receptors in blood vessels
What are contraindications of dopamine?
Should not be used with a MAOI because they are metabolized by MAO
What are the side effects of dopamine?
Tachycardia, nausea, vomiting, angina, headache, and peripheral vasoconstriction
How are dopamine and fenoldopam administered?
IV
What is fenoldopam used for?
Emergency HTN
What are then side effects of fenoldopam?
Reflex tachycardia, headache, and flushing
What is are the 5 drugs classified as indirect acting sympathoimetics agonist?
Amphetamine Methylphenidate Methamphetamine Cocaine Tyramine
What is the MOA of Amphetamine, Methylphenidate, and Methamphetamine?
Increase release of NE from neurons
What is the MOA of Cocaine?
Inhibits reuptake of DA and NE
What is the MOA of Tyramine?
Increases release of DA, NE from nerve terminals
Rapidly hydrolyzed by MAO
What are Amphetamine and Methylphenidate equal DOCs for?
ADHD
What are side effects of Amphetamine, Methylphenidate, and Methamphetamine?
Tremor
Tachycardia
HTN
Psychosis
What is unique about Amphetamine, Methylphenidate, and Methamphetamine?
Only work on intact neurons
Why is Methamphetamine a major drug of abuse?
It has more central actions and fewer peripheral effects
What can cocaine be used for?
Local anesthetic and powerful vasoconstrictor
Rarely used for nasopharyngeal surgery (too addicting)
What are side effects of cocaine?
Severe HTN Stroke Tachycardia Arrhythmias MI Psychosis
What are contraindications of Tyramine?
Pts tx for depression with MAOI, tyramine can lead to severe HTN crisis
What is the specific agonist for alpha 1 receptors?
Phenylephrine
What is the specific agonist for alpha 2 receptors?
Clonidine
What is the specific agonist for B1 receptors?
Dobutamine
What is the specific agonist for B2 receptors?
Albuterol
What is the specific agonist for B3 receptors?
Mirabegron
What happens when you give epinephrine after an alpha blocker?
The effects of epinephrine are reversed (hypotension)
What is dopamine used to treat?
Severe refractory heart failure and is useful if an increase in BP is needed
