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Pharmacology FINAL > Cholinergic Antagonists Part 1 > Flashcards

Cholinergic Antagonists Part 1 Flashcards

1
Q

name 2 kinds of nicotinic antagonists

A

ganglionic blockers
neuromuscular blockers

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2
Q

cholinergic antagonists will cause what kind of responses?

A

FIGHT OR FLIGHT
will mimic sympathetic nervous systek

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3
Q

explain how neuromuscular blockers work

A

they bind to Nm receptors on the postsynaptic membrane of skeletal muscle, PREVENTING the binding of ACh

prevents motor endplate from depolarizing - muscle paralysis

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4
Q

explain how ganglionic blockers work

A

prevent ACh (released from preganglionic neuron) from binding Nn receptor on the ganglia, in both the PSNS and SNS

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5
Q

explain how muscarinic blockers work

A

prevent ACh from binding to the muscarinic receptors on smooth muscle, cardiac tissue, secretory glands, etc

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6
Q

explain the history of cholinergic antagonists

A

from Belladonna plants - Atropa Belladona (source of atropine) and Datura stramonium

preparations of belladonna were used in ancient india and the roman empire used it as poisoning

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7
Q

what are the 3 classes of cholinergic antagonists?

A

naturally occurring alkaloids

semisynthetic derivatives of these alkaloids

synthetic derivatives

*imp to know examples

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8
Q

name 2 naturally occuring alkaloids that are cholinergic antagonists

A

atropine
scopolamine

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9
Q

name 2 semisynthetic derivatives of atropine and scopolamine

A

homatropine

some quaternary ammonium derivatives

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10
Q

name a synthetic derivative that is a cholinergic antagonist

A

ipratropium — has selectivity for some subtypes of the muscarinic receptors

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11
Q

explain the action of muscarinic antagonists

A

prevent the effects of acetylcholine by blocking its binding to muscarinic receptors

these muscarinic receptors can be on effector cells at parasympathetic Neuroeffector junctions, in peripheral ganglia, and in the CNS

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12
Q

TRUE OR FALSE

muscarinic antagonists are not selective

A

FALSE

they are selective for certain subtypes

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13
Q

explain the metabolism and excretion of cholinergic antagonists

A

half of the drug is excreted UNCHANGED in the urine (bc so hydrophilic)

the other half is hydrolyzed and conjugated and ecreted

thus, the effects are gone very quickly in all organs EXCEPT THE EYE

the effect on iris + ciliary muscles may last over 72 hours

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14
Q

explain the mechanism of action of atropine

A

a competitive (reversible) blockade of ACh at muscarinic receptors

prevents the release of IP3 and prevents the inhibition of adenylyl cyclase (M1, M3, M5)

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15
Q

true or false

atropine is not selective for its receptors

A

FALSE

it’s highly selective for muscarinic receptors

binds M1, M2, and M3 - not selective for subgroups, but selective for muscarinic in general

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16
Q

explain the effect of scopolamine and atropine on the CNS

A

Scopolamine has CNS affects like drowsiness and amnesia

atropine has minimal effect on the CNS. slow, long lasting sedative effects

in toxic doses, esp scopolamine can cause hallucination and coma

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17
Q

true or false

atropine is used to treat parkinsons disease

A

FALSE – used to decrease the TREMORS that result from parkinsons

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18
Q

scopolamine is used to treat…..

A

vestibular disturbances - motion sickness
that involves cholinergic transmissionw

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19
Q

what is scopolamine

A

a muscarinic antagonist

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20
Q

name 2 cholinergic inverse agonists

A

atropine
ipratropium

brings original action down below the baseline

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21
Q

true or false

atropine is highly selective for muscarinic receptors

A

true
selective for muscarinic receptors in general but
not selective for M1,M2,M3 – binds all 3

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22
Q

true or false

atropine is competitive with Ach at muscarinic receptors

A

TRUE

reversible and competitive
both bind to same site

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23
Q

true or false

scopolamine is a muscarinic antagonist

A

TRUE

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24
Q

what is mydriasis

A

dilation of the eye

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25
Q

what is cycloplegia

A

weakened contraction of the ciliary muscle

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26
Q

what drug can be used to cause mydriasis and cycloplegia?

A

ATROPINE ****8

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27
Q

true or false

atropine increase lacrimation

A

FALSE - decreases

that’s why used for treatment of mydriasis and cycloplegia

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28
Q

what is the result of atropine on the heart

A

causes TACHYCARDIA (fast heartbeat)
SA and AV node are very sensitive to antimuscarinics

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29
Q

HOW does atropine cause tachycardia

A

by blocking vagal slowing

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30
Q

true or false

atropine causes vasodilation

A

FALSE

vasoconstriction

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31
Q

true or false

atropine can cause increased blood pressure

A

TRUE
due to vasoconstriction + tachycardia

32
Q

what is the effect of an anticholinergic on salivary secretion

A

decreases salivary secretion and causes dry mouth

33
Q

true or false

anticholinergics cause bronchoconstriction

A

FALSE - bronchodilation

34
Q

selective ________ agents are best for treatment of asthma and COPD

A

selective to M3
bronchodilation

M3 is glands, smooth muscle, and endothelium

35
Q

TRUE OR FALSE

anticholinergics have no effect on the uterus

A

TRUE

36
Q

what is the effect of anticholinergics on the genitourinary tract

A

the smooth muscle of the ureters and bladder wall relaxes and SLOWS VOIDING

37
Q

true or false

anticholinergics contract the smooth muscle of the ureters and bladder wall and thus slow voiding

A

FALSE

relax this smooth muscle which slows voiding

38
Q

what is the effect of atropine on sweating?

A

suppresses THERMOREGULATORY sweating

39
Q

as mentioned, atropine suppresses thermoregulatory sweating

explain a negative effect of this

A

in infants and children, even normal doses can cause “atropine fever” bc the body isn’t sweating enough to cool itself down

40
Q

true or false

anticholinergics increase tremors

A

FALSE - decrease

ex: atropine used to treat parkinson’s tremors

41
Q

besides atropine, name 3 other anticholinergics used to treat the tremors from parkinsons

A

benztropine (cogentin)
benzhexol (Artane)
procyclidine

42
Q

name 2 adverse effects of scopolamine

A

sedation, dry mouth

43
Q

true or false

homoatropine is synthetic

A

false - semisynthetic

44
Q

how are anticholinergics used in ophthalmic examination?

A

to cause mydriasis and cycloplegia (ciliary paralysis)

45
Q

for adults and for older children, _____ acting drugs are preferred for ophthalmic examination

A

shorter

46
Q

true or false

cholinomimetics are used for ophthalmic examination

A

false

anticholinergics

47
Q

what kind of preparations are useful to prevent synechia (adhesion) formation in uveitis and iritis?

A

longer lasting anticholinergics like homoatropine

48
Q

name 5 anticholinergics used as eye drops

A

atropine
scopolamine
homatropine
cyclopentolate
tropicamide

49
Q

rank the 5 anticholinergic eye drops in order of duration of action

A

longest:
atropine
scopolamine
homatropine
cyclopentolate
shortest = tropicamide

50
Q

name 2 drugs used pre-surgery to prevent laryngospasm and decrease secretions

A

atropine and scopolamine

51
Q

name 3 drugs used in COPD

A

ipratropium
tiotropium
aclidinium

iprat and tio also used in asthma

52
Q

true or false

to treat asthma and COPD, an anticholinergic can be used

A

true

53
Q

graves disease

A

hyperthyroidism

54
Q

how can atropine be used in people with graves disease?

A

hyperthyroidism can cause atrial fibrillation

atropine can treat

55
Q

_______ can be used in myocardial infarction

A

atropine

bc myocardial infarction leads to bradycardia and decreased cardiac output, potentially leading to fainting

56
Q

atropine can be used in patients with circulating……

A

cardiac M2 antibodies

57
Q

what can treat traveler’s diarrhea

A

atropine + diphenoxylate (low dose opioid) = lomotil

58
Q

how can anticholinergics be used in urinary disorders

A

in bladder spasm and urinary urgency, urinary incontinence

59
Q

what is urinary incontinence and how can it be treated

A

involuntary leakage of urine bc of loss of bladder control

treated with anticholinergics

60
Q

name 3 sources of cholinergic poisoning

A

insecticides (cholinesterase inhibitors)

wild mushrooms

chemical warfare

61
Q

name 2 remedies to cholinergic poisioning

A

-use antimuscarinic therapy (atropine - a tertiary amine)

-use cholinesterase regenerators (pralidoxime)

62
Q

true or false

there is NO way to directly block the nicotinic effects that occur bc of cholinesterase inhibition

A

true

only the muscarinic part - give atropine

63
Q

how is it possible for pralidoxime to be used in cholinergic poisoning

A

pralidoxime can remove the phosphate from the enzyme-organophosphate complex bc it has a higher affinity for the phosphate

enzyme has been regenerated

64
Q

what is mushroom poisoning and what is used to treat it

A

due to too much cholinergic activity - nausea, vomiting, diarrhea, urinary urgency, sweating, salivaiton, bronchoconstrivtion

PARENTERAL ATROPINE IS GIVEN **

65
Q

when an antimuscarinic agent is used to reduce GI motility/secretion, name 2 adverse effects

A

mydriasis
cycloplegia

66
Q

what are the results of atropine poisoning

A

dry mouth
mydriasis
tachycardia
hot and flushed skin
agitation
delirium for as long as 1 week

children and infants = atropine fever. very subject to hyperthermic effects

67
Q

what are ganglionic blockers/ganglion blocking agents?

A

COMPETITIVELY block the action of ACH and similar agonists at Nn receptors of parasymp and symp autonomic ganglia

some also BLOCK THE ION CHANNEL that’s gated by the nicotinic cholinoceptor

68
Q

explain the clinical use of ganglionic blockers

A

they can block all autonomic outflow, and have a LACK of selectivity

this, there are a lot of undesirable effects when used, and thus they have limited clinical use

69
Q

true or false

ganglionic blockers noncompetitively block the action of ACh at Nm receptors of both parasympathetic and sympathetic autonomic ganglia

A

FALSE

competitively block at Nn RECEPTORS
(neuronal nicotinic)

70
Q

name 4 ganglionic blockers***

what are they blocking?

A

blocking action of ACh at Nn receptors of both sympathetic and parasympathetic ganglia

hexamethonium
mecamylamine
tetraethylammonium
decamethonium

71
Q

explain the structure of the ganglionic blockers

A

they are synthetic amines and structurally similar to acetylcholine

(remember - competes with same site ! makes sense that they’re similar)

72
Q

which of the ganglionic blockers was first identified?
what is its duration of action?

A

tetraethylammonium
short duration

73
Q

which of the ganglionic blockers was first used clinically to treat hypertension

A

hexamethonium

74
Q

why was mecamylamine developed originally

A

to improve absorption from GI trat]ct

75
Q

analog of hexamethonium and a depolarizing neuromuscualr blocking agent

A

decamethonium

76
Q
A

Pharmacology FINAL (11 decks)

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