Adrenergic Pharmacology

Question 1

Phenylephrine

Answer 1

alpha-1 agonist, weak beta
longer duration of action (not COMT substrate)

uses: potent vasoconstrictor - reflex bradycardia
nasal decongestant (OTC)
mydriatic agent

Question 2

Methoxamine

Answer 2

selective alpha-1 agonist
longer duration of action (not COMT or MAO substrate)

uses: potent vasoconstrictor for hypotensive state - reflex bradycardia

Question 3

Clonidine

Answer 3

alpha-2 agonist on vascular smooth muscle –> transient hypertension follow by prolonged hypotension due to alpha-2 adrenoceptors in the lower brainstem

uses: antihypertensive

Question 4

Dobutamine

Answer 4

similar to dopamine, beta-1 adrenoceptor agonist with lower beta-2 and alpha-1 activity

uses: inotropic agent for congestive heart failure
dilates renal vasculature to preserve kidney function

Question 5

Terbutaline

Answer 5

beta-2 agonist with some beta-1 activity
long duration (not COMT or MAO substrate)

uses: bronchodilator with minimal cardiac effects
inhaled for bronchospasm/bronchial asthma relief
oral administration for long-term obstructive airway treatment
inhibit premature labor

Question 6

Albuterol

Answer 6

selective beta-2 agonist, similar effects to terbutaline

Question 7

Amphetamine/dextroamphetamine/methamphetamine

Answer 7

induces NE release, indirectly stimulates alpha and beta receptors

uses: sympathomimetic amine stimulates CNS (increase alertness, decrease fatigue, narcolepsy relief, elevate mood, improve concentration)
appetite suppression (but tolerance develops)

Question 8

Ephedrine

Answer 8

NE release from adrenergic nerve terminals (alpha and beta effects), direct alpha and beta agonist
alpha - increase resistance to urine outflow
beta - bronchodilation
CNS stimulant

uses: relieve bronchoconstriction and mucosal congestion with asthma, bronchitis, bronchial spasms
orally effective and long-lasting (not COMT or MAO substrate)
pressor agent and nasal decongestant
treat stress incontinence in women
apetite suppression

Question 9

Metaraminol

Answer 9

alpha-1 agonist with weak beta activity, may be taken up into adrenergic vesicles and replace NE as false nt

uses: pressor agent (alpha-1 activity)
treat hypotensive state
treat bouts of paroxysmal atrial tachycardia

Question 10

Phenoxybenzamine

Answer 10

irreversibly binds alpha receptors

uses: prevent hypertensive crisis of pheochromocytoma during removal
alleviate obstructive benign prostatic hyperplasia
control autonomic hyperreflexia that may occur with spinal cord injuries

SE: orthostatic hypotension, reflex tachycardia, ejaculatory dysfunction, nasal congestion

Question 11

Phentolamine

Answer 11

competitive reversible alpha blockade

uses: blocks hypertensive response to alpha adrenergic agonists, treat hypertension associated with pheochromocytoma
orally of injected for erectile dysfunction

SE: orthostatic hypotension, reflex cardiac stimulation, nasal congestion

Question 12

Prazosin

Answer 12

selective alpha-1 adrenergic antagonist, some alpha-2
inhibitor of cyclic nucleotide phosphodiesterase

uses: treat hypertension (dilation), may decrease CNS sympathetic flow
improve urinary flow for BPH
less likely to produce orthostatic hypotension compared to selective antagonist

first dose phenomenon (give at bed time)

Question 13

Terazosin

Answer 13

prazosin analog, alpha-1 adrenergic antagonist

uses: treat hypertension
treat benign prostatic hyperplasia (reduce obstructive symptoms and urgency
take at bed time due to postural hypotension and syncope

Question 14

Propanolol

Answer 14

beta-1 and beta-2 competitive inhibitor

uses: treat hypertension, angina, MI
treat glaucoma due to decreased aqueous humor secretion
reduce hyperthyroidism symptoms
reduce symptoms of anxiety
treat migraine by blocking vasodilation

Sx: bronchoconstriction, potentiate hypoglycemia. tremor, fatigue, sleep disturbance, nightmares, depression
extensive 1st pass metabolism

Question 15

Metoprolol

Answer 15

beta blocker with higher beta-1 affinity

uses: antihypertensive
depress HR for ischemic heart disease

less tendency for bronchoconstriction

Question 16

Guanethidine

Answer 16

deplete neuronal NE storage

uses: anti-hypertensive (especially if resistant to treatments

SE: orthostatic hypotension, diarrhea, sexual dysfunction

Question 17

Reserpine

Answer 17

inhibits catecholamine uptake in storage vesicles and depletes

uses: mild to moderate hypertension

SE: CNS effects (sedation, nightmares, depression, thoughts of suicide)

Question 18

Methyltyrosine

Answer 18

inhibits tyrosine hydroxylase

uses: manage pheochromocytoma (preoperative and long-term therapy)

SE: sympathetic depression, sedation, anxiety

Question 19

alpha - Methyldopa

Answer 19

converted to alpha-methyl-NE and stored in terminal, released as false transmitter

uses: antihypertensive especially if complicated by renal disease (spares renal blood flow)

SE: sedation, drowsiness, orthostatic hypotension, nasal congestion

preferred for hypertension during pregnancy

Question 20

Cocaine

Answer 20

inhibitor of uptake 1 causes NE accumulation in cleft