Adrenergic Agonists & Antagonists

Question 1

Epinephrine

Answer 1

Receptor: a1, B1 & B2
Use:
- anaphylactic shock
- acute asthmatic attacks
- cardiac arrest
- local anesthetics

Low dose:

• B1 & B2
• dec. PVR
• inc. systalic pressure
• inc. HR

High dose:

• inc. BP
• inc. ventricular contraction
• inc. HR
• vasoconstriction

Question 2

Norepinephrine

Answer 2

Receptors: a1, a2 & B1
Use:
- shock (inc. vascular resistance & inc. BP)

Action:

• peripheral vasoconstriction
• inc. cardiac contractility
• inc. PVR, systolic & diastolic BP
• bradycardia reflex

Question 3

Dopamine

Answer 3

Receptor: D1, B1 & a1
Use: 
- severe CHF
- Cardiogenic shock
- septic shock

Low dose: (D1)

• vasodilation
• inc. GFR
• inc. renal blood flow
• inc. sodium excretion

High dose: (a1)

• vasoconstriction
• inc. BP
• inc. total peripheral resistance

Question 4

Isoproterenol

Answer 4

Non-selective B-agonist
Receptor: B1 & B2
Use:
- stimulate HR, bradycardia/heart block

Effects:

• inc. HR, contraction, cardiac output (B1)
• vasodilation (B2)
• bronchodilation (B2)

Question 5

Dobutamine

Answer 5

B1-selective agonist
Receptor: B1
Use:
- acute heart failure
- cardiogenic shock

Effect:

• mild vasodilation
• inc. myocardial O2 consumption

Question 6

Albuterol
Formoterol
Salmeterol

Answer 6

B2-agonist

Use:
- Acute asthma

Effect:
- bronchodilation

Adverse:

• tremor
• restlessness
• apprehension
• anxiety
• tachycardia

Question 7

Mirabegron

Answer 7

B3-adrenergic agonist

Use:

• overactive bladder
• urinary incontinence

Effect:

• detrusor muscle relaxation
• inc. bladder capacity

Adverse:

• inc. BP
• inc. UTI
• headache

Moderate CYP2D6 inhibitor

Question 8

Phenylephrine

Answer 8

a1-selective agonist

Use:

• decongestant
• mydriasis
• hypotension

Effect:

• vasoconstriction
• dec. HR
• inc. BP
• inc. PVR

Question 9

Clonidine

Answer 9

Partial a2-adrenergic agonist

Use:
- HTN

Adverse:

• lethargy
• sedation
• xerostomia

Effect:
- dec. sympathetic outflow

Question 10

Methyldopa

Answer 10

a2-adrenergic agonist

Use:
- HTN, pregnancy

Adverse:

• sedation
• impaired mental concentration
• xerostomia

Question 11

Brimonidine

Answer 11

Highly selective a2-adrenergic agonist

Use:
- intraocular pressure, glaucoma

Effect:

• dec. aqueous humor production
• inc. outflow

Question 12

Amphetamine

Answer 12

Indirect acting

Use:

• ADHD
• Narcolepsy

Adverse:

• nervousness
• palpitations
• insomnia
• HTN
• hyperthermia
• anorexia

Question 13

Methylphenidate

Answer 13

Indirect acting

Use:
- ADHD, children

Question 14

Tyramine

Answer 14

Can precipitate serious vasopressor episodes in patients taking MAO inhibitors

Question 15

Cocaine

Answer 15

Uptake inhibitor
Block monoamine reuptake
Monoamines accumulate in synaptic space

Adverse:

• seizures
• arrhythmia

Question 16

Atomoxetine

Answer 16

Use:
- ADHD

Uptake inhibitor
Block monoamine reuptake
Monoamines accumulate in synaptic space

Selective inhibitor of NET

Adverse:

• seizures
• arrhythmia

Question 17

Modafinil

Answer 17

Use:
- narcolepsy

Psychostimulant

Inhibits NE and DA transporters
Inc. NE, DA, 5-HT, & glutamate
Dec. GABA

Question 18

Ephedrine

Answer 18

Mixed-acting adrenergic agonist

Use:

• spinal anesthesia
• Myasthenia Gravis

Effect:

• induce release of NE
• activate adrenergic receptors
• long duration

Question 19

Pseudoephedrine

Answer 19

Mixed-acting adrenergic agonist

Use:
- decongestant

Question 20

Phenoxybenzamine

Answer 20

Non-selective a-Adrenergic blocker (irreversible)

Use:
- pheochromacytoma, prior to surgery

Effect:
- + epinephrine = dec. BP

Question 21

Phentolamine

Answer 21

Non-selective a-Adrenergic blocker (reversible)

Use:

• pheochromacytoma, HTN
• pheochromacytoma, diagnosis
• prevention of dermal necrosis
• HTN crisis, stimulant overdose

Question 22

Prazosin
Doxazosin
Terazosin
Tamsulosin

Answer 22

a1-selective Adrenergic blocker

Use:

• HTN
• BPH

Pra. = prototype

Dox. & Ter. = longer half-life

Tam. = less likely to cause orthostatic hypotension & little effect on HTN

Question 23

Propranolol

Nadolol

Answer 23

Non-selective B-blocker

Use:
- esophogeal varices bleeding prevention

Effect:

• slow HR
• dec. myocardial contractility

Contraindicated in patients w/asthma

Adverse:

• bronchoconstriction
• hypoglycemia

Question 24

Timolol

Answer 24

Non-selective B-blocker

Use:
- glaucoma, dec. intraocular pressure

Adverse:

• bronchoconstriction
• hypoglycemia

Question 25

Atenolol | Metoprolol

Answer 25

B1-selective adrenergic antagonist Use: - HTN, impaired pulmonary function - HTN, diabetic

Question 26

Esmolol

Answer 26

B1-selective adrenergic antagonist Use: - control ventricular rate in patients w/a-fib & atrial flutter

Question 27

Labetalol

Answer 27

a1 & B1 blockers (favors B antagonism) Use: - HTN

Question 28

Carvedilol

Answer 28

a1 & B1 blockers Use: - HTN - CHF Antioxidant properties

Question 29

Pindolol

Answer 29

Partial B-agonist Use: - diminished cardiac reserve - bradycardia

Question 30

a-Methyltyrosine | Metyrosine

Answer 30

Inhibitor of NE synthesis Competitive inhibitor of tyrosine hydoxylase Use: - malignant pheochromacytoma

Question 31

Reserpine

Answer 31

Inhibitor of NE storage Effect: - irreversibly blocks VMAT - dec. BP - slow HR Use: - HTN, past

Question 32

Tetrabenazine

Answer 32

Inhibit NE storage Effect: - reversible inhibitor of VMAT Use: - chorea in Huntington's disease