Adrenergic Agonists

Question 1

Compare and contrast norepinephrine and epinephrine’s actions on α1, α2, β1, and β2 adrenergic receptors.

Answer 1

Norepi: acts on α1, α2, β1
Epi: acts on α1, α2, β1, and β2
Epi is slightly more potent than norepi at every receptor they share, and way more potent on β2 receptors

Question 2

Give 1 therapeutic effect and 3 side effects of norepinephrine administration.

Answer 2

Treat acute hypotension; can cause hypertension, arrhythmia, and headache

Question 3

Give 3 uses and 3 side effects of epinephrine administration.

Answer 3

Treat anaphylactic shock, treat glaucoma, contain local anesthetics; can cause palpitation, arrhythmia, and headache

Question 4

Name the 3 α-selective agonists. Which one is a prodrug capable of crossing the blood brain barrier?

Answer 4

Phenylephrine, clonidine, and α-methyldopa.

α-methyldopa is a prodrug (becomes α-methyl-norepinephrine) & can cross the BBB.

Question 5

Phenylephrine is an agonist for what receptor, and what is the principle function of this receptor?

Answer 5

α1 receptor; vasoconstriction

Question 6

Phenylephrine can be used to treat what 2 conditions, and cause cause what 2 side effects?

Answer 6

Treat nasal congestion and postural hypotension; can cause hypertension leading to reflex bradycardia

Question 7

What 2 drugs are CNS α2 agonists that cause central inhibition of sympathetic effects? What is their primary therapeutic effect and related side effect?

Answer 7

Clonidine and α-methyldopa; treat hypertension / cause sedation

Question 8

Give 2 uses for clonidine besides hypertension treatment, and 1 side effect besides sedation.

Answer 8

Treat shock or drug withdrawal; can cause sodium and water retention

Question 9

List the 5 β-selective agonists.

Answer 9

Isoproterenol, dobutamine, albuterol, terbutaline, and ephedrine (ephedrine is also an indirect α agonist)

Question 10

Of the β-selective agonists, which one is “non-selective” and which one is “mixed”? What do those terms mean?

Answer 10

Isoproterenol is non-selective because it works on β1 and β2 receptors.
Ephedrine is a mixed agonist because it increases β2 receptor action both directly and indirectly (indirect increases NE, which affects both α and β receptors)

Question 11

Which β-selective agonist is used to treat cardiac decompensation, shock, and heart block, with possible side-effects of tachyarrhythmia and hypertension? Does it target β1 or β2 receptors?

Answer 11

Dobutamine; β1

Question 12

Which 2 β-agonists are used to treat exercise-induced bronchospasm, mild asthma, and COPD? Do they target β1 or β2 receptors, how long do they need to start working, and how long do their effects last?

Answer 12

Albuterol and terbutaline; β2; 10-15 min; 6-12 hours

Question 13

Give 3 possible complications of albuterol and terbutaline. Which drug is used to relax the uterine smooth muscle during early labor?

Answer 13

Can mask progressively severe inflammation, cause tachycardia, cause muscle tremors; terbutaline is used in early labor

Question 14

Along with dobutamine, what non-selective β-agonist can be used to treat shock and heart block? Give 3 potential side effects of this drug.

Answer 14

Isoproterenol; can cause palpitation, tachyarrhythmia, and headache

Question 15

Even though ephedrine is a direct β2 agonist, it is also an indirect adrenergic agonist used to achieve what 2 therapeutic effects?

Answer 15

To cause nasal decongestion and anorexia (meaning cause decreased appetite, for weight loss drugs)

Question 16

Name the D1 (dopamine) -selective agonist. How long is its half life?

Answer 16

Fenoldopam; 10 minutes

Question 17

What does fenoldopam do in the body?

Answer 17

Increase blood flow to kidneys, brain, and GI tract (via the renal, cerebral, and mesenteric arteries)

Question 18

In order from lowest to highest needed dose, what 3 receptors does dopamine directly activate? When do the indirect effects occur?

Answer 18

D1, β1, α1; NE is also released from the cytoplasm at the medium to high doses (when β1 and α1 are activated)

Question 19

Give 3 conditions where dopamine might be used, and 1 possible side effect of high doses.

Answer 19

Shock, hypotension, and renal failure; can cause α1-mediated vasoconstriction at high doses

Question 20

What 3 adrenergic agonists are used to treat hypotension?

Answer 20

Norepinephrine, dopamine, and phenylephrine (for postural hypotension)

Question 21

What 2 adrenergic agonists are used to treat nasal congestion?

Answer 21

Phenylephrine and ephedrine