Sympathomimetics

Question 1

Epinephrine

Answer 1

B>A

Increases HR (Beta1), increases SBP (Beta1, Alpha1), decreases DBP at low doses (Beta2>Alpha1), increases DBP at high doses (Alpha1>Beta2)

Treats anaphylaxis, open angle glaucoma, asthma, hypotension; alpha effects predominate at higher doses

Question 2

Norepinephrine

Answer 2

A1>A2>B1

Treats hypotension (but produces reflex bradycardia and decreases renal perfusion)

Question 3

Isoproterenol

Answer 3

B1=B2

Produces decreased MAP and increased HR

Question 4

Dopamine

Answer 4

D1=D2>B1>A1

D1: at low doses stimulates vasodilation of renal and mesenteric vessels (increases GFR), at medium doses stimulates B1 receptors, at higher doses stimulates A1 receptors

D2: modulates NT release

Treats unstable bradycardia, heart failure, shock (inotropic and chronotropic effects predominate at high doses)

Question 5

Dobutamine

Answer 5

B1>B2,A1

Treats acute heart failure (inotropic>chronotropic); used in cardiac stress testing

Dobutamine-associated tachycardia and increase in O2-consumption are less pronounced than with dopamine

Toxicity: increases cardiac conduction velocity (can result in arrhythmias

Question 6

Phenylephrine

Answer 6

A1>A2. No B-effect.

Produces vasoconstriction, mydriasis, and decongestion.

Question 7

Albuterol, salmeterol, terbutaline

Answer 7

B2>B1

Albuterol used for acute asthma attacks.
Salmeterol used for long-term asthma/COPD control.
Terbutaline reduces premature uterine contractions.

Question 8

Amphetamine

Answer 8

Indirect general sympathomimetic

Treats narcolepsy, obesity, ADHD

Question 9

Ephedrine

Answer 9

Indirect general sympathomimetic

Treats nasal decongestion, urinary incontinence, hypotension.

Question 10

Cocaine

Answer 10

Indirect general sympathomimetic

Never give beta-blockers if cocaine intoxication is suspected (can lead to unopposed alpha1 activation and extreme HTN!)