Adrenergic Agonists Flashcards
List order of synthesis to get norepi, epi, dopamine, and isoproterenol starting with the initial compound they are all formed from.
L-Tyrosine –> L-Dopa –> Dopamine –> Norepinephrine –> Epinephrine –> Isoproterenol
Where are B3 receptors found?
Adipose (lipolysis), skeletal muscle (thermogenesis), gallbladder, urinary bladder (relax), CNS
Order the following in terms of smallest group on amine to largest. Isoproterenol, norepinephrine, epinephrine
Norepinephrine, epinephrine, isoproterenol
What receptors do blood vessels to skeletal muscle have?
a1 and B2
Why do local anesthetics contain epinephrine?
To achieve local vasoconstriction (via a1) to keep the anesthetic locally for a longer duration
What is the dominant receptor on veins?
a1 - constriction (storing blood)
How much epinephrine is released per day in a normal body?
20-100 ug
What is the effect of epinephrine on immune system?
A. Up- regulate
B. Down- regulate
B
Does dopamine increase contractility (stroke volume) or heart rate more? What does this minimize?
Contractility (stroke volume)
This minimizes oxygen demand/consumption
Does dopamine cross the blood-brain barrier?
No
What drug can you give to people with Parkinson’s disease?
L-DOPA - gets converted to dopamine in nerve terminals
What is the rate-limiting step in synthesis of dopamine, norepi, and epi?
Tyrosine hydroxylase (conversion of L-tyrosine –> L-dopa)
Phenylephrine (Neo-synephrine/Sudafed)
a1 agonist
Vasoconstrictor
- during surgery to raise BP
- nasal decongestants
- priapism
Clonidine (Catapres)
a2 agonist - inhibits further release of NE
Emergency anti-hypertensive, used frequently in ERs
Alpha-methyldopa (Aldomet)
a2 agonist - inhibits further release of NE
Choice anti-hypertensive in pregnant women
What are 2 side effects of Sudafed/Phenylephrine?
high BP, urinary retention
Dobutamine (Dobutrex)
B1 agonist - increases CO
Used in cardiogenic and septic shock to increase CO; also used for cardiac stress test and acute CHF
Albuterol (***terol)
B2 agonist
Asthma, COPD (relieve bronchospasm) - bronchodilator
Salmeterol, Formoterol. Metaproterenol
LABAs - Long-acting B2 agonists
Bronchodilator
Asthma, COPD
Ritodrine (Yutopar)
B2 agonist
Relaxes smooth muscle of uterus by reducing uterine contractions - prevents premature deliveries
What is the drug of choice to treat anaphylactic shock? Name target receptors and how they help.
Epinephrine (epi pen!)
a1 - constricts blood vessels
B1 - CO increases
B2 - bronchodilates & inhibits degranulation of mast cells
What are 5 adverse effects of adrenergic agonists?
Increased blood pressure, tachycardia & cardiac arrhythmias, nervousness/anxiety, hyperglycemia, exaggerated effects with cocaine
What is rebound HTN?
High BP when a drug is stopped abruptly
What is a potential adverse side effect of a2 agonists?
Rebound HTN
What do Beta 3 agonists do? Where are the receptors located?
Promote breakdown of triglycerides - lose weight!
Mostly in adipose tissue and skeletal muscle
Ephedrine
Structural analogs that increase NE levels
Nasal decongestant, used during surgeries to raise BP
What part of the brain do ADD drugs target?
RAS - reticular activating system in midbrain
Tyramine
Precursor to NE - rich in wines and cheeses
Indirect acting agonist - structural analog that increases NE levels and mimics its actions
Contraindicated with MAO inhibitors
What are the neurotransmitter issues in the following conditions?
- Alzheimer’s
- Depression
- Parkinson’s
- Schizophrenia
- ADD
- Alzheimer’s - too little ACh
- Depression - too little serotonin, NE
- Parkinson’s - too little dopamine
- Schizophrenia - too much dopamine
- ADD - too little NE and DA in RAS
What is the treatment for the following conditions:
- Alzheimer’s
- Depression
- Parkinson’s
- Schizophrenia
- ADD
- Increase ACh with esterase inhibitors
- SSRIs, TCAs
- L-dopa
- Dopamine (D2) blockers
- Ritalin, Adderall
Isoproterenol (Isuprel)
Beta-1 = Beta-2 = Beta-3 agonist
Causes vasodilation (why there is marked decreased diastolic pressure), but also increases cardiac force and rate (increase in systolic pressure)
Reference drug
Dopamine (Intropin)
D1, D2 > Beta-1 > alpha-1 agonist
(D1, Gs, high cAMP, EPSP) and
(D2, Gi, low cAMP, IPSP)
Low dose (0.5-2.0 ug/min) - D1 - vasodilation in renal, mesenteric, coronary, and cerebral vasculature, promotes Na+ and H2O excretion
Med dose (5-10 ug/min) - D1 & B1 - increase CO
High dose (10-50 ug/min) - a1 - vasoconstriction
TREATS: Cardiogenic & hypovolemic shock, CHF
Epinephrine (Adrenaline)
alpha-1, alpha-2, beta-1, beta-2, beta-3 agonist
Higher concentration - a1 - vasoconstriction
Lower concentration- B2 - vasodilation
Increases heart rate and contractility (so systolic pressure increases), but dilates blood vessels (so diastolic decreases)
Norepinephrine (Levofed)
alpha-1, alpha-2, beta-1 agonist
Reflex bradycardia - constricts all blood vessels, increasing peripheral resistance, so reflex is to reduce heart rate to try and reduce this pressure
Methylphenidate (Ritalin)
1 drug ADHD
Indirect acting agonist - structural analog that increases NE & dopamine levels and mimic their actions
D-Amphetamine (Adderall)
2 drug aDHD
Indirect acting agonist - structural analog that increases NE & dopamine levels and mimic their actions
