Adrenergic 1

Question 1

MIXED-ACTING ADRENERGIC AGONISTS?

Answer 1

EPHEDRINE
PSEUDOEPHEDRINE
• Induce release of norepinephrine
• Activate adrenergic receptors.

Question 2

Ephedrine structure, pk, and uses

Answer 2

• Not a catecholamine: poor substrate for COMT
and MAO. Long duration of action.
• Excellent absorption orally and penetrates the
CNS.

EPHEDRINE: USES
• Used as a pressor agent, particularly during
spinal anesthesia.
• Used in myasthenia gravis.

Question 3

PSEUDOEPHEDRINE uses?

Answer 3

• One of four ephedrine enantiomers.
• Available over the counter as a component of
many decongestant mixtures.

Question 4

UPTAKE INHIBITORS?

Answer 4

COCAINE
ATOMOXETINE
MODAFINIL

Question 5

MODAFINIL use?

Answer 5

• Psychostimulant.
• MOA not fully known.
• Inhibits norepinephrine and dopamine
transporters.
• Increases synaptic concentrations of
norepinephrine, dopamine, serotonin and
glutamate, and decreases GABA levels.
• Used for the treatment of narcolepsy.

Question 6

ATOMOXETINE use?

Answer 6

• Selective inhibitor of the norepinephrine
reuptake transporter.
• Indicated for the treatment of ADHD.

Question 7

Cocaine use?

Answer 7

• Blocks monoamine reuptake.
• Monoamines accumulate in synaptic space.
• This results in potentiation and prolongation of
their central and peripheral actions.

Question 8

RELEASING AGENTS?

Answer 8

AMPHETAMINE
METHYLPHENYDATE
TYRAMINE
• Cause norepinephrine release from presynaptic
terminals.
• Potentiate effects of norepinephrine produced
endogenously.

Question 9

AMPHETAMINE use?

Answer 9

• Has central stimulatory action.
• Can increase blood pressure by alpha-agonist action
on vasculature as well as beta-stimulatory effects
on heart.
USES
• ADHD
• Narcolepsy

Question 10

METHYLPHENIDATE use?

Answer 10

• Structural analogue of amphetamine.

* Used to treat ADHD in children.

Question 11

Tyramine consequence?

Answer 11

• Found in fermented foods
such as ripe cheese and
Chianti wine.
• Normally oxidized by MAO.
• If the patient is taking MAO
inhibitors, it can precipitate
serious vasopressor
episodes.

Question 12

BRIMONIDINE use?

Answer 12

• Highly selective alpha-2 agonist.
• Given ocularly to lower intraocular pressure in
glaucoma.
• Reduces aqueous humor production and
increases outflow.

Question 13

Methyldopa use and moa?

Answer 13

• Taken up by noradrenergic neurons.
• Converted to alpha-methylnorepinephrine which
activates central alpha2-adrenoceptors.
• This decreases blood pressure.
• Drug of choice for treatment of hypertension
during pregnancy.
• Adverse effects: sedation, impaired mental
concentration, xerostomia.

Question 14

Clonidine use?

Answer 14

• Partial alpha2 agonist.
• Centrally acting antihypertensive.
• Activates central presynaptic alpha2-adrenoceptors.
• Reduces sympathetic outflow. This reduces
blood pressure.
• Adverse effects: lethargy, sedation, xerostomia.

Question 15

PHENYLEPHRINE actions?

Answer 15

alpha 1-SELECTIVE ADRENERGIC AGONISTS
• Vasoconstriction: alpha 1 effect.
• Nasal decongestant . Given orally or topically.
• Mydriatic.
• Used to increase blood pressure in hypotension resulting from vasodilation in septic shock or
anesthesia.
• Used to increase blood pressure and terminate episodes of supraventricular tachycardia.

Question 16

Beta2-ADRENERGIC AGONISTS

Answer 16

• Evoke bronchodilation (beta2 effect)

* Used in asthma.

Question 17

Albuterol use?

Answer 17

SHORT-ACTING

• For management of acute asthma symptoms.

Question 18

Salmeterol & formoterol

Answer 18

LONG-ACTING
• Prolonged duration of action: 12 hours.
• Slow onset of action: not for prompt relief of acute
symptoms.

Question 19

DOBUTAMINE action and uses?

Answer 19

beta 1-SELECTIVE ADRENERGIC AGONISTS
• Predominantly a beta1 agonist.
• Potent inotrope, with comparatively mild chronotropic effects.
• Produces less increase in HR and less decrease in PVR than isoproterenol.
• Causes mild vasodilation.
• Increases myocardial O2 consumption. This is the basis of the dobutamine stress echocardiogram.

DOBUTAMINE: USES
• Management of acute heart failure.
• Management of cardiogenic shock.

Question 20

Isoproterenol uses, moa, effects?

Answer 20

• Activates beta 1 and beta 2 adrenergic receptors
• Increases heart rate, force of contraction, and
cardiac output (beta 1 effect).
• Dilates arterioles of skeletal muscle (beta 2 effect),
resulting in a decrease in peripheral vascular
resistance.
• Diastolic pressure falls. Systolic blood pressure
may remain unchanged or rise.
• Mean arterial pressure typically falls.
• Causes bronchodilation (beta 2 effect).

Isoproterenol use
• Isoproterenol may be used in emergencies to
stimulate heart rate in patients with bradycardia
or heart block

Question 21

Dopamine, what receptors does it act?

Answer 21

• Can activate dopamine, beta and alpha receptors.
• D1 > beta 1 > alpha 1
• The cardiovascular response to dopamine
depends on the dose infused.

Question 22

Low rates of dopamine infusion?

Answer 22

• Dopamine activates D1 receptors, in renal and
other vascular beds, leading to:
• Vasodilation
• Increase in GFR
• Increase in renal blood flow
• Increase in sodium excretion

Question 23

Intermediate rates of dopamine infusion?

Answer 23

• Dopamine activates β1 receptors in the heart,
increasing cardiac output.
• There is negligible activation of β2 receptors.
• Dopamine causes release of NE from nerve
terminals, which contributes to its cardiac effects.
• Dopamine increases SBP.
• DBP is usually not changed significantly.
• MAP is increased.
• PVR is unchanged.

Question 24

High rates of dopamine infusion?

Answer 24

• Dopamine activates vascular alpha 1 receptors,
leading to vasoconstriction and a rise in
blood pressure.
• Total peripheral resistance may be increased

Question 25

Dopamine uses?

Answer 25

• Used in the treatment of severe CHF. • Used in the treatment of cardiogenic and septic shock. • For management of shock intermediate to high rates of infusion are used.

Question 26

Norepinephrine uses receptors act?

Answer 26

* Agonist at alpha 1, alpha 2, and beta 1 receptors | * Little action on beta 2 receptors

Question 27

Norepinephrine effects? uses?

Answer 27

• Causes peripheral vasoconstriction (alpha 1 effect). • Increases cardiac contractility (β1 effect). • Increases peripheral vascular resistance, systolic blood pressure and diastolic blood pressure. • Cardiac output is unchanged or decreased. • The increase in blood pressure triggers a baroreceptor reflex resulting in bradycardia. Norepinephrine uses? • To treat shock because it increases vascular resistance and therefore increases blood pressure.

Question 28

EPINEPHRINE: USES?

Answer 28

• Anaphylactic Shock: drug of choice. • Acute asthmatic attacks. • Cardiac arrest • In Local Anesthetics: Epinephrine increases duration of local anesthesia by producing vasoconstriction at the site of injection.

Question 29

When a low dose is given IV epinephrine actions?

Answer 29

• Peripheral resistance decreases, because beta 2 receptors are more sensitive to epinephrine than alpha 1 receptors. Diastolic pressure falls. • Systolic pressure increases due to increased cardiac contractile force (beta 1 effect). • Heart rate increases (beta 1 effect). • There is no increase in mean blood pressure, so the baroreceptor reflex does not kick in. • Therefore, the effects of epinephrine depend on the dose and the resultant ratio of the alpha 1 to beta 2 responses in the various vascular beds.

Question 30

When a large dose is given IV epinephrine actions?

Answer 30

• There is increase in blood pressure. Due to: 1. Increased ventricular contraction (beta 1 effect). 2. Increased heart rate (beta 1 effect) This may be opposed by the baroreceptor reflex. 3. Vasoconstriction (alpha 1 effect).

Question 31

Describe epinephrine?

Answer 31

• Epinephrine acts as a hormone: after release from the adrenal medulla into the blood it acts on distant cells. • Epinephrine is an agonist at both alpha and beta adrenoceptors. • At low concentrations epinephrine activates mainly beta 1 and beta 2 receptors. • At higher concentrations 1 effects become more pronounced.

Question 32

Epinephrine effects?

Answer 32

• Increases heart rate and contractile force (beta 1 effect). • Cardiac output increases: oxygen demand of the myocardium increases. • Increases renin release (beta 1 effect). • Constricts arterioles in skin and viscera (alpha 1 effect). • Dilates blood vessels of skeletal muscle (beta 2 effect). • Relaxes bronchial smooth muscle (beta 2 effect). • Increases liver glycogenolysis (beta 2 effect). • Increases glucagon release (beta 2 effect). • Increases lipolysis (beta 1 and beta 2 effect).