test 5

Question 1

Adrenergic Agonists

Answer 1

-things that stimulate fight or flight

Question 2

Characteristics of Adrenergic Agonists

Answer 2

Derivatives of β-phenylethylamine
Substitutions on benzene ring or ethylamine side dictate ability to activate α or β and to penetrate CNS
Catecholamines
Noncatecholamines
Substitutions on amine nitrogen

Question 3

Catecholamines

Answer 3

Contain the OH groups on ring
High potency at β receptors
Rapid inactivativated
-degraded by the catechol-O-methyltransferase (COMT) (breaks it down in the synapse) and monoamine oxidase (MAO) (breaks it wond inside of the neuron)
Ineffective orally
–COMT and MAO are present in high concentrations in the gut wall and in the liver
Do not penetrate CNS (because of the OH groups)

Question 4

Noncatecholamines

Answer 4

Do not contain OH groups
Longer duration of action
-Not broken down by the COMT
-only broken down by MAO => poor substrates for it meaning that they last longer in our body
Greater access to CNS (higher lipid solubility because less OH groups)

Question 5

Substitutions on Amine Nitrogen

Answer 5

The bigger the group, the higher the affinity for β

receptors

Question 6

Direct-Acting Adrenergic Agonists

Answer 6

Bind to effector organs without interaction with presynaptic neuron
Examples:
        Epinephrine
        Norepinephrine
        Dopamine
        Dobutamine
        Isoproterenol
        Phenylephrine

Question 7

Epinephrine (Adrenalin)

Answer 7

Endogenous
Acts as both a neurotransmitter and hormone
Released by adrenal medulla (80% Epi 20% NE)
Acts on both α and β receptors

Question 8

NET EFFECT of Epinephrine on the cardiovascular system

Answer 8

• Increased systolic blood pressure with a slight decrease in diastolic pressure due to β2
  receptor mediated vasodilation in the skeletal muscle vascular bed

Question 9

Epinephrine Therapeutic Uses for bradycardia dosage

Answer 9

2-10 μg/min IV titrated to effect to stimulate beta 1

Question 10

Epinephrine Therapeutic Uses: CPR

Answer 10

1 mg IV/IO every 3-5 minutes to stimulate the heart

Question 11

Epinephrine Therapeutic Uses

Answer 11

1. Cardiac Arrest
2. Anaphylactic shock
3. Bronchospasm/acute asthma attack
4. In conjunction with local anesthetics
   - Provides vasoconstriction to localize anesthetic

Question 12

Epinephrine Pharmacokinetics

Answer 12

Rapid onset, short duration
Rapidly degraded by MAO and COMT
IM, IV, SQ, inhalation, endotracheal
NOT orally because a lot of COMT and MAO in the gut wall so it will be metabolized/ broken down
Metabolites excreted by kidney

Question 13

Norepinephrine (Levophed)

Answer 13

Endogenous neurotransmitter of adrenergic nerves

Therapeutic doses affect α and β1 the most (little β2)

Question 14

Norepinephrine Therapeutic Uses

Answer 14

1. Vasodilatory shock

2. Critical hypotension

Question 15

Norepinephrine Therapeutic dosage

Answer 15

0. 5-12 μg/min titrated to effect

- the higher the dose means the patient needs a lot of help

Question 16

Norepinephrine Pharmacokinetics

Answer 16

Duration of action 1-2 minutes
Rapidly metabolized by MAO and COMT
Metabolites excreted by kidney
IV
Extravasation (drug that leaks out of the vein into the tissues) may cause local necrosis!
NE Should not be administered in peripheral veins and should be administered straight into the central line

Question 17

Dopamine

Answer 17

Endogenous precursor of norepinephrine
Functions as a neurotransmitter and hormone
CNS and adrenal medulla

Question 18

Dopamine

Therapeutic Uses

Answer 18

1. Cardiogenic & Septic Shock – DRUG OF CHOICE
2. Renal failure (problem with NE is that it constricts renal vascular beds)
3. Hypotension
4. Severe heart failure

Question 19

Dopamine Pharmacodynamics

Answer 19

Effects are very dose-dependent

Question 20

Dopamine at low doses

Answer 20

(1-2 μg/kg/min)
-acts on dopamine receptors
 Vasodilation to kidneys, brain, viscera
-“renal dose dopamine” increases urine output

Question 21

Dopamine at medium doses

Answer 21

(2-10 μg/kg/min)
-acts on β1 receptors
 Increase cardiac output

Question 22

Dopamine at high doses

Answer 22

(>10 μg/kg/min)
-acts on α receptors
 α activity predominates with profound vasoconstriction

Question 23

Dobutamine (Dobutrex)

Answer 23

Synthetic, direct acting catecholamine

 β1 receptor agonist (selective)

Question 24

Dobutamine Cardiovascular Inotropic Effects compared to dopamine

Answer 24

Dobutamine > Dopamine

Question 25

Dobutamine Cardiovascular Chronotropic Effects compared to dopamine

Answer 25

Dopamine > Dobutamine

Question 26

Dobutamine Therapeutic Uses

Answer 26

Increase cardiac output in acute heart failure
Provides short term support for patients struggling to separate from bypass!
-doesn’t affect periferal vascular resistance and increase HR

Question 27

Isoproterenol

Answer 27

(Isuprel)
Synthetic catecholamine
Nonselective β1
and β2

Question 28

Isoproterenol Therapeutic Uses

Answer 28

1. Second choice drug for cardiac stimulation in emergency situations (heart block, cardiac arrest) (if you don’t have or can’t give epinephrine)
2. Treat bronchospasms during anesthesia (β2 activity)

Question 29

Phenylephrine (Neo-Synephrine)

Answer 29

Synthetic selective α1 agonist
Duration: 20 minutes
Not inactivated by COMT
Lasts longer than epinephrine and ephedrine

Question 30

Phenylephrine Therapeutic Uses

Answer 30

Treat hypotension
Especially those with rapid heart rate
Treat paroxysmal supraventricular tachycardia
Nasal decongestant when applied topically or orally
-Phenylephrine is VERY commonly used in perfusion to increase the SVR and the arterial pressure!!!

Question 31

Neo-Synephrine Dosing

Answer 31

Titrated to effect
Start with a test dose
-some patients respond quickly so it could constrict a lot
IV bolus
◦ 50-500 micrograms
IV infusion
◦ 10 or 15 mg in 250 mL IV fluid (40 to 60 micrograms/mL)
-give when you get to max flow and P is still to low

Question 32

Neo-Synephrine Calculations

Answer 32

PRACTICE

Question 33

Indirect-Acting Adrenergic Agonists

Answer 33

Indirectly increase endogenous levels of NE and Epi
Cause the release
Inhibit the reuptake
Inhibit the degradation

Question 34

Mixed-Action Adrenergic Agonists

Answer 34

Effects similar to epinephrine but less potent and longer duration of action
Cardiac stimulation
Vasoconstriction
Increased systolic and diastolic BP
Mild CNS stimulation

Question 35

Ephedrine therapeutic uses

Answer 35

Still used clinically to treat hypotension if Epi and Neo aren’t working

Question 36

Pseudoephedrine therapeutic uses

Answer 36

Nasal and sinus congestion

Question 37

Adverse Affects of Adrenergic Agonists

Answer 37

• arrhythmias
• headache
• hyperactivity
• insomnia
• nausea
• tremors