Adrenergic Alpha Blockers

Question 1

MOA of centrally acting alpha 2 agonists

Answer 1

Decrease, modulate, or regulate neurotransmitter release at the nerve endings, leading to the decrease in activity of the sympathetic nervous system

Question 2

Alpha 2 agonists

Answer 2

Clonidine
Methyldopa
Guanfacine

Question 3

Selective Alpha 1a receptors are found in the __; indication; agents

Answer 3

Prostate smooth muscle
Urinary bladder neck
Treatment of BPH
Tamsulosin
Alfuzosin
Silodosin

Question 4

Sympathetic depressants arranged according to degree of ability to cause postural hypotension

Answer 4

Ganglionic blockers
Conventional alpha blockers
Adrenergic neuron blockers
Centrally acting alpha 2 agonists

Question 5

Guandethedine

Answer 5

Centrally acting alpha 2 receptor agonists
Polar
Cant traverse BBB
No CNS side effects

Question 6

Mechanism of sodium retention in sympathetic depression

Answer 6

Decreased blood pressure–> decreased perfusion–>JG cells create rennin–> RAAS activation–> sodium and water retention–> edema

Question 7

Side effects of alpha adrenoreceptor antagonists

Answer 7

Postural hypotension
Sedation or depression
Increased GIT motility and diarrhea
Sexual dysfunction
Increased blood volume and sodium retention
Nasal stuffiness
Reflex tachycardia

Question 8

Side effects of beta adrenoceptor antagonists: CVS, Respiratory, Metabolic

Answer 8

CVS: decreased HR, CO, force of contraction
Respo: bronchoconstriction, bronchospasms
Metabolic: hypoglycemia, decreased lipolysis

Question 9

Location of alpha 2a receptors

Answer 9

Brainstem medulla: decreases sympathetic outflow from vasomotor center to decrease BP
Medullary salivation center: decreases secretions–>dry mouth/xerostomia

Question 10

Location of alpha 2b

Answer 10

Vascular smooth muscle causing vasodilation

Question 11

Therapeutic uses of alpha 2 agonists

Answer 11

Hypertension

Ocular hypertension and open angle glaucoma

Question 12

Clonidine: solubility, MOA

Answer 12

Lipid soluble–> sedation
MOA:
-central presynaptic a2a receptors–> decreased BP
-presynaptic peripheral a2 receptors–> suppression of NE release
-postsynaptic peripheral a2b receptors–> transient increase in BP, then hypotension

Question 13

Therapeutic use of Clonidine

Answer 13

Mild to moderate hypertension

Wide angle glaucoma

Question 14

Methyldopa MOA

Answer 14

Stimulates central presynaptic a2 adrenoceptors in the brainstem–> decrease sympathetic outflow: decreased BP
Act as false neurotransmitter in the periphery

Question 15

Used as treatment for hypertension during pregnancy

Answer 15

Methyldopa

Question 16

Guanfacine MOA

Answer 16

stimulate alpha2a receptors in the brainstem–> decreased sympathetic outflow–> decreased BP

Question 17

Brimonidine

Answer 17

To decrease IOP in ocular hypertension and open angle glaucoma
Crosses BBB
Causes hypotension and sedation but milder than clonidine

Question 18

Apraclonidine

Answer 18

Minimal systemic effect
Does not cross BBB
decrease secretion of aqueous humor for ocular hypertension and open angle glaucoma

Question 19

Treatment for pheochromocytoma

Answer 19

Phenoxybenzamine

Question 20

Phentolamine

Answer 20

Conventional alpha adrenergic blocker
a1=a2
Prone to produce reflex tachycardia

Question 21

Phenoxybenzamine

Answer 21

Irreversible recepter blockade

A1»»»»»A2 (100:1)

Question 22

Selective a1A receptor blocker for BPH

Answer 22

Alfuzosin

Tamsulosin