7- Cholinomimetric Drugs

Question 1

bind directly to and activate muscarinic or nicotinic cholinoceptos

Answer 1

direct-acting cholinomimetics

Question 2

produce their effects by inhibiting the action of acetylcholinesterase, thus preventing the destruction of endogenous Ach

Answer 2

indirect-acting cholinomimetics

Question 3

direct acting muscarinic agonists (6)

Answer 3

Acetylcholine
Methacholine
Carbachol
Bethanechol
Muscarine
Pilocarpine

Question 4

direct acting muscarinic agoinst that are choline esters (4)

Answer 4

acetylcholine
methacholine
carbachol
bethanechol

Question 5

direct acting muscarinic agonist that are alkaloids (2)

Answer 5

muscarine

pilocarpine

Question 6

direct acting alkaloid cholinoceptors (4)

Answer 6

muscarine
pilocarpine
nicotine
succinylcholine

Question 7

indirect acting reversible cholinesterase inhbitors (5)

Answer 7

edrophonium
neostigmine
physostigmine
denepezil
tacrine

Question 8

indirect acting irreversible organophosphate cholinesterase inhibitors (4)

Answer 8

echothiphate
malathion
parathion
sarin

Question 9

why do choline esters have poor GI absorption and poor CNS distribution?

Answer 9

cationic quaternary ammonium compounds that make them insoluble in lipid

Question 10

which of the choline esters have methyl groups giving them a longer half life?

Answer 10

methacholine and bethanechol

Question 11

which of the choline esters are insusceptible to cholinesterase?

Answer 11

carbachol and bethanechol

Question 12

effects of choline esters on the cardiovascular system

Answer 12

• hypotension from direct vasodilation
• bradycardia at high doses
• slowed conduction and prolonged refractory period of AV node

Question 13

effects of choline esters on GI system

Answer 13

• increased tone and increased contractile activity of gut
• increased acid secretion
• nausea, vomiting, cramps, and diarrhea

Question 14

effects of choline esters on genitourinary tract

Answer 14

involuntary urination from increased bladder motility and relaxation of sphincter

Question 15

effects of choline esters on eye

Answer 15

miosis: contraction of sphincter muscle, resulting in reduced intraocular pressure

contraction of ciliary muscle; accomodated for near vision

Question 16

effects of choline esters on respiratory system

Answer 16

bronchoconstriction

Question 17

effects of choline esters on glands

Answer 17

increased secretory activity, resulting in increased salivation, lacrimation and sweating

Question 18

Ach: _______ destruction by AchE

Answer 18

rapid

–> limited clinical use

Question 19

muscarinic effects of Ach

Answer 19

cardio - low doses = vasodilation –> tachycardia
high doses = bradycardia; decreased AV conduction and negative inotropy

bronchial constricition and increased secretion

salivary excretion, tears, sweat

urinary bladder contraction

short lasting miosis in eye

Question 20

nicotinic effects of Ach

Answer 20

not commonly seen since Ach does not penetrate the fat surrounding skeletal muscle and autonomic ganglia

Question 21

clinical use of Ach

Answer 21

eye surgery (short-lasting miosis)

provocation test in coronary angiography (dx coronary vasospasm)

Question 22

how does methacholine compare to Ach

Answer 22

similar in action

longer half life

Question 23

diagnosis of bronchiolar hypersensitivity:

Answer 23

methacholine challenge

excessive bronchoconstriction via M3 receptors in bronchial muscle in asthmatic pts.

Question 24

therapeutic doses of carbachol

Answer 24

both nicotinic and muscarinc effects

Question 25

high doses of carbachol

Answer 25

may induce cardiac arrest

Question 26

topical application for glaucoma

Answer 26

carbachol contracts ciliary muscle which enlarges canal of schlemm and increases drainage of aqueous humor and decreases intraocular pressure

Question 27

what are the indications for bethanechol?

Answer 27

-gastric atony (after vagotomy to reduce reflux; increases lower esophageal tone) - gastric emptying abnormalitie - urinary retention (in absence of obstruction)

Question 28

where does bethanechol predominately act?

Answer 28

M3

Question 29

effects on bethanechol on genitourinary and gastrointestinal tract?

Answer 29

increase detrusor tone, decrease outlet resistance of internal sphincter increase motility and secretion

Question 30

does muscarine have nicotinic acitivity?

Answer 30

no

Question 31

signs of muscarine poisoning

Answer 31

salivation, sweat, tear flow abdominal pain, nausea, diarrhea, blurred vision, dyspnea symptoms subside w/i 2 hrs severe may lead to death

Question 32

which is more potent muscarine or Ach?

Answer 32

muscarine (100x) also longer duration of action than Ach because not broken down by AchE

Question 33

Pilocarpine predominate effects

Answer 33

opthalmic via M3 contracts iris sphincter muscles --> miosis frees entrance to canal of Schlemm (therapy ofr narrow-angle glaucoma) enhances tone of trabecular network (therapy for wide-angle glacuoma) contract ciliary muscle for accommmodation and loss of far vision

Question 34

drug of choice for glaucoma

Answer 34

pilocarpine

Question 35

what does a pilocarpine hypersensitivity indicate?

Answer 35

PANS dysfunction test on autonomic state

Question 36

why is pilocarpine given for xerostomia?

Answer 36

given orally to stimualte saliva secretion

Question 37

contraindications for direct acting cholinoceptor agonists

Answer 37

peptic ulcers GI tract disorders asthma

Question 38

drug interactions with anti-muscarinc properties (do not use with direct acting cholinoceptor agonists)

Answer 38

quinidine (antiarrhythmics) procainamide (antiarrhythmics) tricyclic antidepressants

Question 39

prototypical agonist for nAch receptors

Answer 39

nicotine

Question 40

action of nicotine on Nm receptors

Answer 40

- skeletal muscle contraction - fasiculations, spasm - depolarizing blockade

Question 41

action of nicotine on Nn receptors

Answer 41

increased HR both symp and para effects depending on system peripheral vasoconstriciton increased gut motility and secretion increased RR nausea and vomiting via emetic chemoreceptors

Question 42

clinical indication for nicotine

Answer 42

aid smoking cessation

Question 43

used to differentiate myasthenia from cholinergic crisis

Answer 43

edrophonium - will show imporvement - short acting

Question 44

do neostigmine and pyridostigmine go into the CNS?

Answer 44

no (quartenary amines)

Question 45

what are the clinical uses for neostigmine and pyridostigmine

Answer 45

ileus, urinary retention, myasthenia, reversal of non-depolarizing NM blockers

Question 46

does physostigmine enter the CNS?

Answer 46

yes (tertiary amine)

Question 47

clinical use for physostigmine

Answer 47

glaucoma

Question 48

antidote in atropine overdose

Answer 48

physostigmine

Question 49

do donepezil and tacrine enter CNS?

Answer 49

yes - lipid soluble

Question 50

clincal use donepezil and tacrine

Answer 50

alzheimer disease

Question 51

nerve gas

Answer 51

sarin

Question 52

malathion and parathion are...

Answer 52

insecticides

Question 53

which of the organophosphates has clinical use?

Answer 53

echothiophosphate for glaucoma this group has limited clinical use because they are irreversible inhibtors of AchE

Question 54

DUMBBELSS

Answer 54

symptoms of intoxication of cholinesterase inhibitors ``` diarrhea urination miosis bronchiolar constriction bradycardia excitement lacrimation sweating salivation ```

Question 55

antidote for cholinesterase inhbitor intoxication

Answer 55

atropine (muscarinc receptor agonist)

Question 56

what drug could be used to regenerate AchE?

Answer 56

pralidoxim aka 2PAM