Adrenergic Agonists

Question 1

Catecholamines differ in

Answer 1

1. Oral usability
2. Duration of action
3. CNS penetration

Question 2

Catecholamines are composed of

Answer 2

Catechol and ethylamine group

Question 3

3 types of Adrenergic agnoists

Answer 3

Direct, indirect, mixed acting

Question 4

How does tyramine act as a indirect acting sympathomimetic?

Answer 4

Tyramine displaces NA from cytoplasmic pool (sympathomimetic) -> taken by uptake 1 (NE transporter) into terminal then into vesicle by VMAT in exchange for NA which is taken up by uptake1 in exchange for tyramine. (if not metabolised by MAO)

Question 5

What are direct acting catecholamines?

Answer 5

Non-selective catecholamines -> NA + AD

Question 6

What are Indirect Acting Sympathomimetics?

Answer 6

Drugs that cause NA release in the absence of nerve stimulation

Question 7

a1 direct acting agonists and usage

Answer 7

Oxymetazoline, phenylephrine

-> eye drops + runny nose

Question 8

Noradrenaline is ______ in the gut

Answer 8

inhibitory

Question 9

What is adrenaline reversal?

Answer 9

Presence of an a antagonist causes vasoconstrictor action to be blocked unmasking b2 mediated vasodilator -> fall in bp

Question 10

Why are adrenaline stimulating drugs used during cardiac arrest?

Answer 10

Increases HR without bp change - no vagal drive to heart

Question 11

Why are adrenaline stimulating drugs used for asthma?

Answer 11

b2 selective agonist -> bronchodilaton

Question 12

Which adrenaline stimulating drug is used for cardiac arrests?

Answer 12

Dobutamine, b1 agonist

Question 13

Why are adrenaline stimulating drugs used to treat glaucoma?

Answer 13

Reduces rate of aqueous humour prod. through a2 on ciliary body + veins (absorption)

Question 14

Which adrenaline stimulating drug is used to treat glaucoma?

Answer 14

Dipivefrine (prodrug)

Question 15

What type of glaucoma are adrenaline stimulating drugs used on?

Answer 15

open-angle (filtration angle between iris and cornea) simple glaucoma (intra-ocular pressure above 21mmHg)

Question 16

What other drug can be used to treat open angle simple glaucoma?

Answer 16

Brimonidine, a2 agonist

Question 17

What type of agonist is used during an anaphylactic shock? How is relief achieved?

Answer 17

Direct acting agonist, adrenaline. Counteracts laryngeal oedema, bronchospasm + hypotension (from histamine)
-> vasoconstriction through a1 reduces laryngeal oedema, b1 increase bp + bronchodilator (b2) Physiological antagonism

Question 18

Adrenaline is used for vaso____ alongside ____ to prolong _____

Answer 18

constriction, LA’s, anaesthesia

Question 19

Propranolol is more selective for

Answer 19

beta

Question 20

Phentolamine is very selective for

Answer 20

alpha

Question 21

Isoprenaline causes

Answer 21

vasodilation -> bp falls

-> tachycardia + direct b mediated force of contraction increases

Question 22

Isoprenaline is very selective for

Answer 22

beta

Question 23

Adrenaline is more potent on

Answer 23

beta than alpha

Question 24

Adrenaline acts in

Answer 24

the adrenal medulla

Question 25

Noradrenaline is more potent on

Answer 25

alpha than beta

Question 26

Noradrenaline acts on

Answer 26

Post-ganglionic sympathetic nerve terminals

Question 27

Isoprenaline causes smooth muscle to

Answer 27

relax

Question 28

Dopamine is dose dependant. Which receptors are affected at different doses?

Answer 28

Low- D receptors Med: B1 receptors High: a1 receptors Med + high doses can cause acute severe heart failure and hypertensive shock

Question 29

Direct acting agonists are

Answer 29

selective

Question 30

a2 direct acting agonists and usage

Answer 30

Clonidine -> hypertension + ADHD

Question 31

B1 direct acting agonists and usage

Answer 31

Dobutamine for increase cardiac output

Question 32

B3 direct acting agonists and usage

Answer 32

Mirabegron -> overreactive bladder

Question 33

B2 direct acting agonists - short acting

Answer 33

Albuterol, terbutaline

Question 34

B2 direct acting agonists - long acting

Answer 34

Salmeterol, formotorol

Question 35

How do indirect acting agonists work?

Answer 35

Enhance NA + AD by inhibition of reuptake/breakdown - > block reuptake of NA/dopamine in reward system - > a1 + b1 -> increase BP + HR

Question 36

Ephedrine

Answer 36

Mixed action agonist -> not catechloamine - > direct binding, release of stored NA from pre-sympathetic terminals - vasoconstriction - bronchodilation

Question 37

Pseudoephedrine

Answer 37

Mixed action agonist: - > long duration - > vasoconstriction and broncho muscle relaxation - > nasal passages decrease mucus production