Adrenergic Receptor Agonists

Question 1

Norepinephrine (Levophed)

Answer 1

Class: Non-selective agonist

Mech: Agonist for a1, a2, B1

Therapeutics: Acute Hypotension

Tox: Hypertension, arrhythmias, headache

Question 2

Epinephrine

Answer 2

Class: Non-selective agonist

Mech: Agonist a1, a2, B1, B2

Therapeutics: Anaphylactic shock,
Combined with local anesthetic,
Glaucoma

Tox: Palpitation, arrhythmias, headaches

Question 3

Amphetamine

Answer 3

Class: Indirect acting

Mech: Increases release of preformed cytoplasmic NE

Thera: ADHD, narco, recreation

Tox: HTN, insomnia, anxiety, arrhythmias

Question 4

Isoproterenol

Answer 4

Class: Non-selctive B agonist

Mech: Agonist B1, B2

Thera: Shock, heart block

Tox: Palpitation, tachyarrhythmia, headache

Question 5

Dobutamine

Answer 5

Class: B1-selective B agonist

Mech: Agonist: B1

Thera: Cardiac decompensation, shock, heart block

Tox: Tachyarrhythmias, HTN

Question 6

Albuterol

Answer 6

Class: B2-selective agonist

Mech: Agonist: B2

Thera: Prevent or reverse exercise-induced bronchospasm, mild asthma, COPD

Tox: Can mask progressively severe inflammation, tachycardia, muscle tremor

Misc: 10-15 min to take action, 6-12 duration, nebulizer delivers more but greater SEs, oral is least effective that need high SE-inducing dose,

Question 7

Terbutaline

Answer 7

Class: B2 selective B agonist

Mech: Agonist: B2

Thera: Prevent or reverse exercise-induced bronchospasm, mild asthma, COPD

Tox: Can mask progressively severe inflammation, tachycardia, muscle tremor

Misc: 10-15 min to take action, 6-12 duration, nebulizer delivers more but greater SEs, oral is least effective that need high SE-inducing dose,

Question 8

Phenylephrine

Answer 8

Class: a1 selective a agonist

Agonist: a1

Thera: Nasal congestion, postural hypotension

Tox: HTN, reflex bradycardia

Question 9

Clonidine

Answer 9

Class: a2 selective a agonist

Mech: CNS agonist a2

Thera: HTN, shock, withdrawal from drug dependence

Tox: Sedation

Question 10

Alpha-methyldopa

prodrug

Answer 10

Class: a2 selective a agonist

Mech: Metabolite (a-methylnorepinephrine) activates CNS a2 receptors

Thera: Hypertension

Tox: Sedation

Misc: Prodrug form crosses BBB

Question 11

Fenoldopam

Answer 11

Class: Selective dopamine agonist

Mech: Agonist D1 only

Thera: Increase blood flow at renal, mesenteric, and cerebral arteries

Tox: None

Misc: Approx 10 min halflife

Question 12

Dopamine

Answer 12

Class: Mixed acting (direct and indirect)

Mech: Agonist: D1, a1, B1

Thera: Shock, renal failure, hypotension

Tox: Vasoconstriction at high doses

Misc: Low dose=Direct @ D1 receptors.
Medium dose=Direct @ B1 with some indirect NE release.
High does=Direct @a1, some indirect NE release.