ANS Sympathomimetics

Question 1

Phenylephrine

Answer 1

direct α1 agonist. maintain BP, mydriatic, decongestant, not inactivated by COMT. TX: headache, insomnia

Question 2

Midodrine

Answer 2

direct α1 agonist. prodrug, treat orthostatic hypotension orally. TX: supine hypertension, urinary retention

Question 3

Clonidine

Answer 3

direct α2 agonist. treat hypertension orally and withdrawal. IV admin increases BP then reduces sympathetic activity and BP. t1/2 12 hrs. Adverse dry mouth, sedation, sex dysfunction

Question 4

Isoproterenol

Answer 4

direct β1,2 agonist. stimulates heart β1, vasodilator + bronchodilator β2, increase CO with decreased BP, COMT met., contraindicated w/ coronary a. disease. Adverse palpitations, tachycardia, headache, flushing

Question 5

Dopamine

Answer 5

β1 agonist (relatively selective). t1/2 2min, NET MAO COMT met., severe CHF, shock, no long term benefits. low dose: increase renal/mesenteric blood flow, natriuresis, vomiting. med dose: positive inotropic. high dose: vasoconstriction

Question 6

Dobutamine

Answer 6

β1 agonist (relatively selective). t1/2 2.5 min, positive inotropic, treat cardiogenic shock, resembles DA w/o low dose effect, no vasodilation because slight α1 agonist.

Question 7

Albuterol

Answer 7

β2 agonist, rapid onset 1-5 min, short duration 3-4 hrs, oral/inhaled/nebulized, treat bronchospasm + COPD. TX: tremor, tachycardia

Question 8

Terbutaline

Answer 8

β2 agonist, similar to albuterol but only subQ, treat bronchospasm + COPD, delay premature labor

Question 9

Ritodrine

Answer 9

β2 agonist, uterine relaxant, IV admin, may increase maternal morbidity

Question 10

Salmeterol

Answer 10

β2 agonist, aerosol admin, long duration 12-24 hrs, slow onset so not for acute, treat asthma (+exercised induced), bronchospasm, COPD. CYP34A met. TX: tremor, tachycardia

Question 11

Ephedrine

Answer 11

direct αβ/indirect agonist. releases NE, oral, t1/2 3-6hrs, treats asthma, enuresis, decongestant, CNS stimulant

Question 12

Pseudoephedrine

Answer 12

indirect agonist. releases NE, nasal decongestant, topical/oral, less CNS stimulation than Ephedrine. TX: A fib, ventricular premature beats, hypertension, insomnia

Question 13

Methylphenidate

Answer 13

indirect agonist. analog of amphetamine, treat ADHD

Question 14

Tyramine

Answer 14

indirect agonist. byproduct of tyrosine met. by liver/GI MOA. releases catecholamines when admin. parenterally. inactive oral. Enhanced by MAOI, can cause hypertensive crisis

Question 15

Cocaine a.k.a Yayo

Answer 15

indirect agonist. inhibits DA and NE reuptake, powerful, local anesthetic. TX: sudden death from cardiac arrhythmia/arrest, seizure, respiratory arrest; paranoia, hypertension, angina, hyperthermia

Question 16

MAOI (phenelzine* + selegiline**)

Answer 16

indirect agonist. accumulation and increased release of catecholamines, irreversibly inhibits MAO A* (increases NE EPI DA Serotonin) MAO B (increases DA). treat depression and Parkinson’s

Question 17

COMT inhibitor (Entacapone)

Answer 17

indirect agonist. inhibits degradation of DA, extends t1/2 of levodopa, treat Parkinson’s

Question 18

Apraclonidine

Answer 18

direct α2 agonist. topical, reduces IOP, does not cross BBB

Question 19

Brimonidine

Answer 19

direct α2 agonist. topical, reduces IOP in open angle glaucoma, decreases aq humor production, increases outflow, crosses BBB. Adverse hypotension, sedation