sympathomimetics

Question 1

epinephrine: most affected receptors, applications

Answer 1

beta effects more important than alpha effects at low doses; alpha effects predominate at high doses. used for anaphylaxis, open angle glaucoma, asthma, and hypotension.

Question 2

norepinephrine: affected receptors, applications

Answer 2

alpha 1> alpha2 > beta1. used for hypotension, but decreases renal perfusion

Question 3

isoproterenol affected receptors, applications

Answer 3

beta receptor agonist. used to evaluate tachyarrhythmias, but can worsen ischemia

Question 4

dopamine affected receptors, applications

Answer 4

D1=D2 > beta >alpha. used for unstable bradycardia, heart failure, shock. inotropic and chronotropic effects predominate at high doses.

Question 5

dobutamine affected receptors, applications

Answer 5

B1 > B2, alpha. used for heart failure and cardiac stress tests

Question 6

phenylephrine affected receptors, applications

Answer 6

alpha 1 > aplpha 2. used for hypotension, ocular procedures (mydriatic), rhinitis

Question 7

albuterol affected receptors, applications

Answer 7

(salmeterol and terbutaline are like this too). Beta2 > beta 1. used for acute asthma.

Question 8

terbutaline affected receptors, applications

Answer 8

like albuterol, B2> B1. used to prevent premature uterine contractions.

Question 9

salmeterol affected receptors, applications

Answer 9

used for long term asthma/COPD control

Question 10

amphetamine: mechanism and clinical application

Answer 10

indirect general agonist and reuptake inhibitor. it also releases stored catecholamines. good for narcolepsy, obestiy, and ADD

Question 11

ephedrine affected receptors, applications

Answer 11

indirect general agonist. releases stored catecholamines. used for nasal deconsgestion and treatment of urinary incontinence and hypotension.

Question 12

cocaine

Answer 12

indirect general agonist and reuptake inhibitor. it causes vasoconstriction and local anesthesia. NEVER give a beta blocker to someone with cocaine intoxication because of unopposed alpha-1 activation and extreme hypertension.

Question 13

compare and contrast norepinephrine and isoproterenol: effects on BP, and HR, with explanation

Answer 13

NE is an agonist at alpha 1 > alpha 2 > beta 1 receptors. isoproterenol works on beta receptors. therefore, NE will cause increased blood pressure d/t alpha-mediated vasoconstriction. high pressures can cause bradycardia. Isoproterenol, on the other hand, causes beta-2 mediated vasodilation: decr. mean arterial pressure and incr. HR through beta 1 and reflex actity

Question 14

clonidine

Answer 14

an alpha-2 agonist that acts as a sympatholytic. used for hypertensive urgency. doesn’t decr. renal blood flow. also for ADHD, severe pain (off-label uses like ethanol and opioid withdrawal)

Question 15

clonidine toxicity

Answer 15

CNS depression, bradycardia, hypotension, resp. depression, small pupil size

Question 16

alpha-methyldopa

Answer 16

used for HTN in pregancy and is safe in pregancy. it is an alpha 2 agonist/sympatholytic. toxicity: direct coombs positive hemolytic anemia and SLE-like syndrome