Adrenergic Drugs Flashcards
1
Q
Autonomic Nervous System
A
- The SNS is the counterpart of the parasympathetic nervous system
- Together they make up the ANS
- They provide a checks-and-balances system for maintaining the normal homeostasis of the autonomic functions of the human body
2
Q
Adrenergic Drugs
A
- Drugs that stimulate the sympathetic nervous system (SNS)
- Adrenergic agonists
- Sympathomimetics
- Mimic the effects of SNS neurotransmitters (catecholamines)
- Norepinephrine (NE)
- Epinephrine EPI)
- Dopamine
3
Q
Catecholamines
A
- substances that can produce a sympathomimetic response
- Metabolized by two enzymes:
- Monoamine oxidase=MAO
- Catechol ortho-methyltransferase=COMT
- Endogenous
- epinephrine, norepi, dopamine - Synthetic
- Dobutamine, phenylephrine
4
Q
MOA for Adrenergic Drugs
A
- Direct-acting sympathomimetic
- Binds directly to the receptor and causes a physiologic response
- Indirect-acting sympathomimetic
- causes release of catecholamine from storage sites (vesicles) in nerve ending
- catecholamine then binds to receptors and causes a physiologic response - Mixed -acting sympathomimetic
- Directly stimulates the receptor by binding to it
- Indirectly stimulates the receptor by causing the release of stored neurotransmitters from vesicles in the nerve endings
5
Q
Alpha-Adrenergic Receptors
A
- Divided into alpha1 and alpha2 receptors
- differentiated by their location on nerves
- Alpha1-adrenergic receptors
- Alpha2-adrenergic receptors
- control the release of neurotransmitters
6
Q
Drug effects of Alpha-Adrenergic Receptors
A
- stimulation of alpha-adrenergic receptors on smooth muscles results in:
- vasoconstriction of GI smooth muscles
- Relaxation of GI smooth muscles (decreased motility)
- Constriction of bladder sphincter
- Contraction of uterus
- Male ejaculation
- Contraction of pupillary muscles of the eye (dilated pupils)
7
Q
Beta-Adrenergic Receptors
A
- All are located on postsynaptic effector cells
- Beta1-adrenergic receptors-located primarily in the heart
- Beta2-adrenergic receptors-located in smooth muscle of the bronchioles, arterioles, and visceral organs
- Responses
- Bronchial, GI, and urterine smooth muscle relaxation
- Glycogenolysis
- Cardiac stimulation
- Bronchial, GI, and urterine smooth muscle relaxation
8
Q
Drug effects of Beta-adrenergic receptors
A
- stimulation of beta1-adrenergic receptors on the myocardium, artrioventricular (AV) node, and sinoatrial (SA) node results in cardiac stimulation
- increased force of contraction (POSITIVE INOTROPIC EFFECT)
- Increased heart rate (POSITIVE CHRONOTROPIC EFFECT)
- increased conduction through AV node (POSITIVE DROMOTROPIC EFFECT)
9
Q
Drug effects of Beta-adrenergic receptors
A
- Stimulation of beta2-adrenergic receptors on the airways results in
- Bronchodilation (relaxation of the bronchi)
- Other effects:
- Uterine relaxation
- Glycogenolysis in the liver
- Increased renin secretion in the kidneys
- Relaxation of GI smooth muscles (decreased motility)
10
Q
Dopaminergic Receptors
A
- an additional adrenergic receptor
- stimulated by dopamine
- caused dilation of the following blood vessels, resulting in increased blood flow
- renal
- mesenteric
- coronary
- cerebral
11
Q
Cardiovascular effects for Blood Vessels
A
receptors Alpha1 and beta2 causing VASOCONSTRICTION, VASODILATION
12
Q
cardiovascular effects for cardiac muscle
A
Beta1 Increased contractility
13
Q
Cardiovascular effects for AV node
A
Beta1 increased heart rate
14
Q
Cardiovascular effects for SA node
A
Beta1 increased heart rate
15
Q
Genitourinary effect on bladder sphincter
A
Alpha1 constriction
16
Q
Genitourinary effect on Penis
A
Alpha1 ejaculation
17
Q
Genitourinary effect on Uterus
A
Alpha1 and beta2 contraction and relaxation
18
Q
Gastrointestinal effect on muscle
A
Beta2 and alpha decreased motility
19
Q
Gastrointestinal effect on sphincters
A
Alpha1 constriction
20
Q
Respiratory effect on bronchial muscles
A
Beta2 dilation
21
Q
Endocrine effect on Liver
A
Alpha1 and Beta2 glycogenolysis
22
Q
Ocular effect on Pupils
A
Alpha1 dilation (mydriasis)
23
Q
Bronchodilators
A
drugs that stimulate beta2-adrenergic receptors of bronchial smooth muscles, causing relaxation, resulting in bronchodilation
24
Q
Examples of bronchodilators
A
albuterol, ephedrine, epinephrine, formterol, levalbuterol, metaproterenol, pirbuterol, and salmeterol
25
Treatment of nasal congestion
- Intranasal (topical) application causes contrction of dilated arterioles and reduction of nasal blood flow, thus decreasing congestion
- Alpha1-adrenergic receptors
26
Examples of nasal congestion
-ephedrine, naphazoline, oxymetazoline, phenylephrine, and tetrahydrozoline
27
Temporary relief of conjunctival congestion
- alpha-adrenergic receptors
| - examples: epinephrine, naphazoline, phenylephrine, tretrahydrozoline
28
Reduction of intraocular pressure and dilation of pupils: treatment of open-angle glaucoma
- Alpha-adrenergic receptors
| - Examples: epinephrine and dipivefrin
29
Overactive Bladder Indications
- relaxes the detrusor muscle during the storage phase of the bladder fill cycle
- increases bladder storage capacity
- Mirabegron (Myrbetriaq)
30
Cardioselective sympathomimetics
- used to support the heart during cardiac failure or shock; various alpha and beta receptors affected
- Rhythm makers
- Examples: Dobutamine, ephedrine, fenoldooam, midodrine, dopamine, epinephrine, phenylephrine, norepinephrine
31
Adverse Effects of Alpha-adrenergic
- headache, restlessness, excitement, insomnia, euphoria
- chest pain, vasoconstriction, reflexive bradycardia, palpitations, dysrhythmias
- Anorexia, dry mouth, nausea, vomiting, taste changness
32
Adverse Effects of Beta-adrenergic drugs
- mild tremors, headache, nervousness, dizziness
- increased heart rate, palpitations, fluctuations of blood pressure
- sweating, nausea, vomiting, muscle cramps
33
Toxicity and Management of Overdose
- From excessive CNS stimulation
- seizures
- Intracranial bleeding due to extreme elevation of blood pressure
- Short half-lives, thus effects are short-lived
- Symptom management and support the respiratory and cardiac system
34
Vasoactive Adrenergics: Dobutamine
- Beta1-selective vasoactive adrenergic drug that is structurally similar to the naturally ocurring catecholamine dopamine
- Stimulates beta1 receptors on heart muscle; increases cardiac output by increasing contractility, which increases the stroke volume, especially in patients with heart failure
- IV drug; given by continuous infusion
35
Dopamine
- naturally occurring catecholamine neurotransmitter
- potent dopaminergic as well as beta1-and alpha1 adrenergic receptor activity
- Low dosages: can dilate blood vessels in the brain, heart, kidneys, and mesentery, which increases blood flow to these areas
- Higher infusion rates: improve cardiac contractility and output
- Highest doses: vasoconstriction (alpha1-adrenergic receptor activity)
36
Epinephrine
- Endogenous vasoactive catecholamine
- acts directly on both the alpha-and beta-adrenergic receptors of tissue innervated by the SNS
- prototypical nonselective adrenergic agonist
- Adninstered in emergency situations
- One of the primary vasoactive drugs used in many advanced cardiac life support protocols
37
Fenoldopam (Corlopam)
- periperal dopamine-1 agonists
- used to lower blood pressure by inducing arteriolar vasodilation through stimulation of D1 receptors
- short-term treatment of severe hypertension
- increases renal blood flow
- given parenterally
38
Midodrine (Proamatine)
- Prodrug that is converted in liver to its active form: desglymidodrine
- Alpha1-adrenergic receptors stimulator
- used for symptomatic orthostatic hypotension
- oral dosing
- should not be given within 4 hours of bedtime
39
Mirabegron (Myrbetriq)
- Beta3 agonist
- relaxes detrusor muscle leading to increased bladder capacity
- used for treatment of overactive bladder
- Adverse effects: hypertension, UTI, Headache, Nasopharyngitits, nausea, dizziness
40
Nrepinephrine (Levophed)
- stimulates alpha-adrenergic receptors
- causes vasoconstriction
- direct-stimulating beta-adrenergic effects on the heart
- no stimulation to beta2-adrenergic receptors of the lung
- treatment of hypotension and shock
- administered by continuous infusion
41
Phenylephrine (Neo-Synephrine)
- works almost exclusively on the alpha-adrenergic receptors
- used primarily for short-term treatment to raise blood pressure in patients in shock
- control of supraventricular tachycardias
- vasoconstriction in regional anesthesia
- Topical ophthalmic drug
- nasal decongestant
42
Chronic Lung disease education
- avoid factors to exacerbate their condition
- encourage fluid intake if permitted
- educate patients about proper dosing, use of equipment and equipment care
- educate on appropriate use of inhalers
43
What may happen if you over use a nasal decongestant?
may cause rebound nasal congestion or ulcerations
44
What happens if you administer two adrenergic drugs together?
may precipitate severe cardiovascular effects such as tachycardia or hypertension
45
Can adrenergic drugs be given orally?
no, digestive enzymes will destroy
