Adrenergic Drugs

Question 1

Prazosin (Minipress)

Answer 1

Alpha-1 Antagonist
Selective alpha-1 blocker
Primary use - antihypertensive
Very little alpha 2 activity means no reflex tachycardia
Induces vasodilation, decreases venous return
Also improves urinary flow
First dose phenomenon - CNS effects the first time its taken

Question 2

Methoxamine

Answer 2

Alpha-1 Agonist
Not a substrate for COMT or MAO — very long half life
Primary use - vasoconstrictor

Question 3

Clonidine

Answer 3

Alpha-2 Agonist
Primary use - Treat Hypertension
Central suppression of BP via action on alpha 2 receptors
Transient spike in BP, followed by prolonged hypotension

Question 4

Reserpine

Answer 4

Sympatholytic
Globally depletes catecholamines
Inhibits amine and dopamine uptake, irreversible
Further blocks NE storage and synthesis
Extremely long acting (weeks)

Side Effects: significant CNS effects (depression, sedation, suicide)

Question 5

Propanalol

Answer 5

Nonselective Beta-1 and Beta-2 antagonist
Primary uses - antihypertensive, heart disease (via decreasing HR)
At rest has little effect on a normal heart
Also treats glaucoma (via decreasing intraocular pressure)
Can reduce peripheral symptoms of hyperthyroidism

Side Effects: bronchoconstriction due to beta 2 antagonist action. Should not be used in patients with underlying lung disease
Also can cause profound hypoglycemia in diabetics
Membrane stabilizing effect, reduces membrane excitability

Question 6

Phentolamine

Answer 6

Alpha Antagonist
Nonselective competitive alpha blocker
Primary use - pheochromocytoma
Poor antihypertensive because it induces reflex tachycardia
Also used in erectile dysfunction

Side Effects: orthostatic hypotension, reflex cardiac stimulation, nasal congestion

Question 7

Phenylephrine

Answer 7

Alpha-1 Agonist
Not a substrate for COMT — long half life
Primary use - VASOCONSTRICTOR
Treat hypotension
Nasal decongestant

Question 8

Phenoxybenzamine

Answer 8

Alpha Antagonist
Covalent, irreversible nonselective alpha blocker
May take days to recover alpha activity
Primary Use - treatment of PHEOCHROMOCYTOMA
Also used in benign prostate hypertrophy

Side Effects: orthostatic hypotension, nasal congestion, ejaculatory dysfunction

Question 9

Ephedrine

Answer 9

Mixed Acting Adrenergic Agonist
Indirectly induces NE release, direct alpha/beta agonist
Primary Use - bronchodilation (mostly displaced by beta 2 selectives), urinary incontinence (promotes retention), appetite suppression

Question 10

Cocaine

Answer 10

Prevents uptake from removing NE from the synaptic cleft, prolonging signaling

Question 11

Terbutaline/Albuterol

Answer 11

Beta-2 Agonist
Not a substrate for COMT or MAO — very long half life
Primary use - BRONCHODILATOR
Better than non-selective beta agonists because they do not cause cardiac stimulation, unless you use too often
Inhibit mast cell secretion
Inhalation limits side effects

Question 12

Methyl Tyrosine

Answer 12

NE Synthesis Inhibitor
Inhibits tyrosine hydroxylase, resulting in global catecholamine decrease
Blocks tyrosine —> L-DOPA conversion
Primary use - pheochromocytoma
Given pre-operatively to reduce risks when excising pheos

Side effects: sympathetic depression

Question 13

Metroprolol

Answer 13

Cardioselective Beta-1 blocker
Primary uses - antihypertensive, ischemic heart disease (via decreasing HR)
At rest has little effect on a normal heart
Does not cause bronchoconstriction

Question 14

Beta-2 Agonists

Answer 14

Bronchodilators

Question 15

Alpha-1 Agonists

Answer 15

Vasoconstrictor

Treat hypotension, stimulate mydriasis, rhinitis (used as a decongestant)

Question 16

Dobutamine

Answer 16

Beta-1 Agonist
Primary use - INOTROPE
Treat Congestive Heart Failure, increase cardiac contractility
Also promotes vasodilation
Side effects - tolerance may develop

Question 17

Beta-3 Agonists

Answer 17

Treat urinary urgency or overactive bladder

Question 18

Amphetamine (Vyvanse, Adderal)

Answer 18

Indirect Adrenergic Agonist
Enhances NE release and acts as a powerful CNS stimulant
Primary use - SCHEDULE I, but reduces fatigue, increases alertness, improves physical performance

Side Effects: appetite suppression, dependency, tolerance

Question 19

Beta-1 Agonists

Answer 19

Vasodilator, treat congestive heart failure
Stimulate cardiac contractility
Dilates renal vasculature

Question 20

Metraminol

Answer 20

Mixed Acting Adrenergic Agonist
Indirectly replaces NE in storage granules, direct alpha 1 agonist
Primary use - treat hypotension

Question 21

Methyldopa

Answer 21

NE Synthesis Inhibitor
False neurotransmitter, displaces NE and binds with much lower affinity
Converted to alpha methyl norepinephrine in the body
Primary use - antihypertensive, probably via action on central alpha 2 receptors (similar to clonidine)

Side effects: CNS effects including sedation, drowsiness
Also sympathetic depression (orthostatic hypotension, nasal congestion, etc)

Question 22

Alpha-2 Agonists

Answer 22

Vasodilator

Anti-hypertensive, treat hypertensive crisis

Question 23

Guanethidine

Answer 23

Sympatholytic
Displaces NE from storage vesicles and exposes them to degradation by MAO. Also interferes with vesicle release
Primary use - strong antihypertensive. Vasodilator
Good oral availability with long half life

Side Effects: orthostatic hypotension, GI upset & diarrhea, male sexual disturbance