Cholinergic Antagonists Flashcards Preview

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Flashcards in Cholinergic Antagonists Deck (78)
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1
Q

What is an agonist?

A

Molecule found in nature/made in lab

binds to specific receptor –> elicit same response as endogenous compound would when bound

2
Q

What is an antagonist?

A

Molecule found in nature/made in lab

incompletely binds to specific receptor

blocks usual response from occurring

can also observe opposite response –> dry mouth instead of salivation

3
Q

Can the dose amount of agonist/antagonist alter observed effects? If so why?

A

Yes

higher doses can engage in more receptors or more receptor types –> exaggerated response + signs of toxicity (more pathways triggered)

4
Q

What are the 2 types of Cholinergic antagonists?

A

Muscarinic Antagonists

Nicotinic Antagonists

5
Q

What is another name for a cholinergic antagonist?

A

Anticholinergic

6
Q

What is another name for a muscarinic antagonist?

A

parasympatholytic

antimuscarinic

7
Q

What does a muscarinic antagonist do?

A

Block effects of parasympathetic autonomic discharge

8
Q

What are 2 examples of muscarinic antagonists?

A

Atropine

Scopolamine

9
Q

What are the 2 types of nicotinic antagonists and what do they do?

A

Ganglionic Blockers - block ALL outflow past ganglionic level

Neuromuscular Blockers - prevent skeletal muscles from working properly

10
Q

What are some examples of Nicotinic Antagonists?

A

Tetraethylammonium

Tubocurarine

Succinylcholine

11
Q

What is another name for Atropine?

A

Hyoscyamine

12
Q

Where does atropine come from?

A

Origianally isolated from plants –> Atropa belladonna

Derivatives synthesized in lab

13
Q

What is atropine?

A

classic cholinergic antagonist

14
Q

What are some other drugs that have similar structures and produce similar effects as Atropine?

A

Antihistamines

Phenothiazine antipsychotics

Tricyclic antidepressants

15
Q

What are the actions of atropine?

A

Resversible block muscarinic receptors –> prevents ACh from binding to those sites

16
Q

Will Atropine block actions of exogenously administered cholinergics or endogenous acetylcholine?

A

Typically blocks actions of EXOGENOUSLY administered cholinergics

17
Q

Which tissues are most sensitive to Atropine?

A

Salivary

Bronchial

Sweat glands

18
Q

What other tissues are effected by Atropine?

A

Eye

CV system

GI tract

GU tract

CNS

19
Q

What are the CNS effects of anticholinergics and why do they produce those effects?

A

Atropine –> minimal CNS effect; can’t cross BBB

Scapolamine –> drowsiness/amnesia; can cross BBB

20
Q

What are some signs of scopolamine toxicity?

A

CNS excitement

CNS agitation

hallucinations

coma

21
Q

Which antimuscarinic is used in Parkinson’s and what is it treating?

A

Benztropine

treat tremors

22
Q

Why would you use antimuscarinics to treat Parkinson’s?

A

In parkinson’s there is to much ACh

Benztropine will block ACh effects

23
Q

How would you treat motion sickness and how would you administer the drug?

A

Scopolamine patches

Injection, orally, transdermal patch

24
Q

What are the effects of Antimuscarinics on the Eye?

A

block cholinergic stimulation of pupillary constrictor muscle –> mydriasis (unopposed sympathetic dilation)

prevent contraction of ciliary muscle –> cycloplegia (loss of accommodation) –> unfocused near vision –> blurry vision

Reduce lacrimal secretion –> dry eye

can DANGEROUSLY worsen narrow angle glaucoma (lack of outflow of aqueous humor)

25
Q

What are the therapeutic uses of antimuscarnics on the eye?

A

used for opthamologists to view the retina –> mydriasis and cycloplegia = good in this case

But not commonly used anymore

26
Q

How are antimuscarnics administered in the eye?

A

Drops

Ointment

27
Q

What are the low does effects of antimuscarinics ( .5 mg atropine) on the cardiovascular system?

A

atropine block M1 receptors only –> bradychardia; ACh still can bind to M3

28
Q

What are the effects of moderate to high doses of antimuscarinics (1-5 mg atropine) on the cardiovascular system?

A

block M2 receptors in SA/AV nodes that USUALLY slow HR –> tachycardia

like inhibiting brakes on HR

29
Q

What are the effects of toxic doses of antimuscarinics (>10 mg atropine) on the cardiovascular system?

A

intraventricular condition block –> inhibits electrical pulse generation in pacemaker nodes

30
Q

Why does antimuscarinics (atropine) have little effect on BP?

A

There are minimal innervations from parasympathetic system

31
Q

What are the therapeutic uses of antimuscarinics (atropine) in CV disorders?

A

During acute MI or SA/AV node function –> bradycardia; so you want to give moderate dose of antimuscarinic (atropine) –> block M2 receptors –> increase HR

32
Q

What are the effects of anticholinergics on the Respiratory System?

A

Bronchodilation –> better air flow

Reduce/dry-up secretion

33
Q

What are some anticholinergic drugs used for respiratory disorders and how are they given?

A

Ipratropium (Atrovent) and Tiotropium (Spiriva)

given as inhaler or nebulizer –> bronchodilation

34
Q

What are Ipratropium (Atrovent) and Tiotropium (Spiriva) used to treat?

A

Asthma

COPD

35
Q

What are some other uses of atropine or scopolamine regarding the respiratory system?

A

Dry upper/lower respiratory secretions prior to surgery or in mechanically vented patients

36
Q

What are the effects of antimuscarinics on the GI tract?

A

reduced motility –> prolong gastric emptying time/slowing intestinal transit time

reduce salivary secretion –> dry mouth (common side effect)

reduce gastrointestinal secretions

37
Q

What are some therapeutic uses of atropine in GI disorders?

A

reducing GI secretions (BUT NOT ACID IN STOMACHE)

treat diarrhea

38
Q

What is Lomotil and what is it used for?

A

Diphenoxylate + atropine

slow down gut motility –> treat somache bugs

39
Q

What are the effects of Antimuscarinics on the GU tract?

A

relaxation of smooth muscle in ureter/bladder wall –> reduces voiding

40
Q

Why wouldn’t you want to give an antimuscarinic to a pt with benign prostatic hyperplasia (BPH)?

A

can worsen or causes urinary retention

41
Q

What are some therapeutic uses of anticholinergics in urinary disorders?

A

urinary tract spasms associated w/ inflammation, surgery, or neurologic conditions

incontinence

42
Q

What is the classic anticholinergic used to treat urinary disorders?

A

Oxybutinin

43
Q

How would you treat muscarinic toxicity?

A

anticholinergics!

Atropine

2-PAM (pralidoxime)

44
Q

How would you most likely get mushroom poisoning?

A

Eating wild mushrooms –> contain natural cholinergic agents

45
Q

What are the 2 types of mushroom poisoning?

A

Rapid onset

Delayed onset

46
Q

Describe rapid onset mushroom poisoning and how you would treat it?

A

Occurs w/ in 15 - 30 minutes after ingestion

muscarinic side effects

treat w/ atropine

47
Q

Describe delayed onset mushroom poisoning and how would you treat it?

A

Occurs 6 - 12 hours after ingestions

muscarinic side effects + renal/hepatic toxicity

treat w/ supportive care (atropine = ineffective)

48
Q

What type of sweat gland problem can be treated with muscarinic antagonists?

A

eccrine hyperhidrosis

49
Q

What is the name of the drug that could be used to treat eccrine hyperhidrosis?

A

Glycopyrrolate

50
Q

What are some adverse side effects of anticholinergics?

A

Dry mouth (dry as a bone)

Mydriasis (blind as a bat)

Tachycardia

Hot, Flushed skin (red as a beet)

Agitation (mad as a hatter)

Urinary retention (can’t pee)

Visual changes (can’t see)

Constipation (can’t shit)

51
Q

What are some drugs that produce anticholinergic side effects?

A

TCAs

Antihistamines

Phenothiazine antipsychotics

52
Q

What are 3 contraindications of anticholinergic use?

A

Gluacoma (especially narrow angle)

Elderly men with BPH (benign prostatic hyperplasia)

Gastric Ulcers

53
Q

Why would glaucoma be a contraindication for anticholinergics?

A

anticholinergics cause angle closure –> prevent outflow of aqueous humor

54
Q

Why is BPH a contraindication for anticholinergics?

A

can worsen or causes urinary retention

55
Q

Why are gastric ulcers a contraindication for anticholinergics?

A

anticholinergics –> slowed gastric emptying –> aggregate ulcer symptoms

56
Q

What does the toxin from clostridium botulinum do?

A

targets presynaptic proteins that block release of ACh

57
Q

What is the result of the toxin from clostridium botulinum?

A

paralysis of skeletal muscle

decreased activity @ parasympathetic and sympathetic synapses

inhibition can last weeks –> months

58
Q

What is the toxin from clostridium botulinum used to treat?

A

blepharospasm

other focal muscle spasms

hyperhidrosis of palsm/axillae

cosmetic removal of wrinkles

59
Q

What do ganglionic blocking agents do?

A

block ACh (and agonists) @ nicotinic receptors of parasympathetic/sympathetic ganglia

60
Q

What is another name for ganglionic blocking agents?

A

Nondepolarizing competitive antagonists

61
Q

What are some ganglionic blocking agents?

A

Tetraethylammonium (TEA)

Hexamethonium (C6)

Mecamylamine

Trimethaphan

62
Q

What kinds of effects of ganglionic blockers (sympathetic or parasympathetic)?

A

Mixed sympathetic/parasympathetic effects

63
Q

What are some of the CNS effects of ganglionic blockers?

A

Sedation

Tremor

Choreiform movements

Mental aberrations

64
Q

What are some of the ganglionic blocker effects on the eye?

A

Cycloplegia = Loss of accommodation

Moderate dilation of pupil

65
Q

What are some of the ganglionic blocker effects on the CV system?

A

Tachycardia

66
Q

What are some of the ganglionic blocker effects on the GI tract?

A

decrease secretions

decrease motility

67
Q

What are the therapeutic uses of ganglionic blockers?

A

Really only used in pharmacological research

68
Q

What do neuromuscular blockers do?

A

@ synapse

block neuromuscular transmission between motor end plate and nicotinic receptors on skeletal muscle

69
Q

What are the 2 groups of neuromuscular blockers?

A

Nondepolarizing (antagonists)

Depolarizing (agonists)

70
Q

What do non depolarizing neuromuscular blockers do?

A

block ACh from binding nicotinic receptors

prevent depolarization of muscle fibers and inhibit contraction

result in very relaxed (paralyzed) muscle

71
Q

Do nondepolarizing neuromuscular blockers bind competitively or noncompetitivelly?

A

competitively

72
Q

How can you terminate the effect of non depolarizing neuromuscular blockers?

A

AChE inhibitors

will increase ACh and overcome the competition for blocked receptors

73
Q

When are non depolarizing neuromuscular blockers used?

A

during surgery –> muscle paralysis (relaxation)

ICU

74
Q

How do non depolarizing neuromuscular blockers differ from each other?

A

differ by onset of action, half-life, means of elimination

75
Q

What is a classic example of depolarizing neuromuscular blocker?

A

Succinylcholine

76
Q

What does depolarizing neuromuscular blockers do?

A

binds to nicotinic receptors on skeletal muscle

acts like ACh

proivdes constant stimulation of receptor

Initially cause depolarization

Continued presence prevents transmission of further impulses

causes resistance to further depolarization –> paralysis

77
Q

What are 2 advantages of depolarizing neuromuscular blockers?

A

rapid onset

short duration of action

give same effect as non polarizing antagonist

78
Q

What are the therapeutic uses of depolarizing neuromuscular blockers like succinylcholine?

A

Facilitate intubation

electroconvulsive shock therapy