cholinergic inhibition

Question 1

what are the direct acting anticholinergics?

Answer 1

none

Question 2

muscarinic receptors are what kind of receptor?

Answer 2

GPCRs

Question 3

where are M1 receptors found?

Answer 3

gastric parietal cells

Question 4

where are M2 receptors found?

Answer 4

heart

Question 5

where are M3 receptors found?

Answer 5

most tissues

Question 6

where are M4 and M5 receptors found?

Answer 6

CNS

Question 7

Gi vs Gq

Answer 7

• M1, M3, M5 use Gq and stimulate phospholipase C (elevates Ca++)
• M2, M4 use Gi and inhibit adenylyl cyclase (activate K+ channels)

Question 8

are there muscarinic blockers specific for subsets of M receptors?

Answer 8

• in vitro yes, but not in clinical practice

Question 9

how do muscarinic blockers work?

Answer 9

• block parasympathetic transmission at end organs

- produce inhibitory effect

Question 10

how does atropine work?

Answer 10

• anti-DUMBBELSS

- unopposed sympathetic actions

Question 11

effects of atropine toxicity

Answer 11

1) delirium (mad as a hatter)
2) mydriasis, blurred vision (blind as a bat)
3) dry mouth, skin, eyes, bronchi (dry as a bone)
4) temp up (hot as a hare)
5) redness (red as a beet)
6) pee pee dance

Question 12

clinical uses for atropine

Answer 12

1) bronchodilation Rx for asthma
2) constipation Rx for IBS
3) tachycardia and hypertension Rx for bradycardia

Question 13

what are the M specific anticholinergics?

Answer 13

1) atropine

2) scopolamine

Question 14

what are the two subclasses of Nm specific anticholinergics?

Answer 14

depolarizing and non-depolarizing

Question 15

what are the depolarizing Nm specific anticholinergics?

Answer 15

succinylcholine - cholinolytic agonist

Question 16

what are the non-depolarizing Nm specific anticholinergics?

Answer 16

benzylisoquinolines
- d-Tubocurarin
- cisatracurium
aminosteroids
- pancuronium
- vercuronium
- rocuronium

Question 17

what are the Nn specific anticholinergics?

Answer 17

trimethaphan - ganglionic blocker

Question 18

what are the major clinical uses for scopolamine?

Answer 18

1) motion sickness

2) inducing anesthesia

Question 19

how is scopolamine given?

Answer 19

transdermal patch

Question 20

side effects of scopolamine

Answer 20

• same as atropine

- plus CNS depression/excitation

Question 21

muscarinic blockers for urgency and bladder spasms?

Answer 21

1) oxybutynin

2) glycopyrrolate

Question 22

muscarinic blocker for parkinsons

Answer 22

benztropine

Question 23

muscarinic blockers for asthma/COPD

Answer 23

• ipratropium - short action

- tiotropium - long action

Question 24

muscarinic blockers for cholinergic poisoning

Answer 24

• atropine

- pralidoxime (when organophospates are involved)

Question 25

what is the one clinical use of Nm blockers?

Answer 25

inhibit skeletal muscle activity during surgery

Question 26

how does succinylcholine work?

Answer 26

acts like ACh at Nm receptors but binds and depolarizes longer and stronger causing paralysis. ACh can't bind because succinylcholine is already there

Question 27

what are some possible adverse effects of succinylcholine?

Answer 27

1) muscle fasciculations 2) hyperkalemia 3) histamine release 4) malignant hyperthermia (rare)

Question 28

contraindications for succinylcholine

Answer 28

1) family hx of malignant hyperthermia 2) hyperkalemia 3) burns, trauma, tissue injury 4) heart failure

Question 29

how do non-depolarizing Nm blockers work on receptors?

Answer 29

reversible competitive inhibition

Question 30

what does d-Tubocurarine do?

Answer 30

paralysis in fully conscious patients

Question 31

what is the best way to reverse non-depolarizing Nm blockers?

Answer 31

neostygmine

Question 32

what is the best way to reverse depolarizing Nm blockers?

Answer 32

time - neostygmine will produce muscarinic syndrome

Question 33

side effects of non-depolarizing Nm blockers

Answer 33

- tachycardia - hypertension - histamine release - ganglionic and muscarinic side effects

Question 34

what are the routes of excretion for the non depolarizing Nm blockers?

Answer 34

pancuronium - renal vecuronium - hepatic rocuronium - hepatic cisatracurium - inactivated by plasma ChE so...... renal disease - not pancuronium liver disease - not vecuronium or rocuronium renal AND liver disease - cisatracurium plasma ChE deficiency - not cisatracurium

Question 35

when is trimethaphan used?

Answer 35

- hypertensive crisis | - dissecting aortic aneurysm

Question 36

atropine F

Answer 36

25%

Question 37

atropine half life

Answer 37

2 hours

Question 38

atropine metabolism/excretion

Answer 38

- 50% metabolized to tropine and tropic acid | - 50% excreted unchanged in urine

Question 39

atropine routes

Answer 39

oral, IV, IM, rectal

Question 40

ipratropium indications

Answer 40

- COPD | - acute asthma

Question 41

ipratropium metabolism

Answer 41

hepatic

Question 42

ipratropium half life

Answer 42

2 hours

Question 43

ipratropium pharmacodynamics

Answer 43

- non-selective muscarinic blocker - promotes degradation of cGMP - decreased contractility of smooth muscle - does not cross blood brain barrier

Question 44

ipratropium special considerations

Answer 44

not a short acting bronchodilator, cannot be used as a rescue drug for acute asthma

Question 45

trimethaphan routes

Answer 45

oral, IM, IV

Question 46

trimethaphan pharmacodynamics

Answer 46

- blocks Nn receptors at ganglion shutting down both SANS and PANS. - causes vasodilation and histamine release

Question 47

two other drugs that work like tubocurarine

Answer 47

- rocuronium | - cisatracurium