Cholinergic Antagonists Flashcards Preview

Pharmacology Test #2 > Cholinergic Antagonists > Flashcards

Flashcards in Cholinergic Antagonists Deck (78):
1

What is an agonist?

Molecule found in nature/made in lab

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

2

What is an antagonist?

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

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

Yes

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

4

What are the 2 types of Cholinergic antagonists?

Muscarinic Antagonists

Nicotinic Antagonists

5

What is another name for a cholinergic antagonist?

Anticholinergic

6

What is another name for a muscarinic antagonist?

parasympatholytic

antimuscarinic

7

What does a muscarinic antagonist do?

Block effects of parasympathetic autonomic discharge

8

What are 2 examples of muscarinic antagonists?

Atropine

Scopolamine

9

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

Ganglionic Blockers - block ALL outflow past ganglionic level

Neuromuscular Blockers - prevent skeletal muscles from working properly

10

What are some examples of Nicotinic Antagonists?

Tetraethylammonium

Tubocurarine

Succinylcholine

11

What is another name for Atropine?

Hyoscyamine

12

Where does atropine come from?

Origianally isolated from plants --> Atropa belladonna

Derivatives synthesized in lab

13

What is atropine?

classic cholinergic antagonist

14

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

Antihistamines

Phenothiazine antipsychotics

Tricyclic antidepressants

15

What are the actions of atropine?

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

16

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

Typically blocks actions of EXOGENOUSLY administered cholinergics

17

Which tissues are most sensitive to Atropine?

Salivary

Bronchial

Sweat glands

18

What other tissues are effected by Atropine?

Eye

CV system

GI tract

GU tract

CNS

19

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

Atropine --> minimal CNS effect; can't cross BBB

Scapolamine --> drowsiness/amnesia; can cross BBB

20

What are some signs of scopolamine toxicity?

CNS excitement

CNS agitation

hallucinations

coma

21

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

Benztropine

treat tremors

22

Why would you use antimuscarinics to treat Parkinson's?

In parkinson's there is to much ACh

Benztropine will block ACh effects

23

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

Scopolamine patches

Injection, orally, transdermal patch

24

What are the effects of Antimuscarinics on the Eye?

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

What are the therapeutic uses of antimuscarnics on the eye?

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

But not commonly used anymore

26

How are antimuscarnics administered in the eye?

Drops

Ointment

27

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

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

28

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

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

**like inhibiting brakes on HR**

29

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

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

30

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

There are minimal innervations from parasympathetic system

31

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

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

What are the effects of anticholinergics on the Respiratory System?

Bronchodilation --> better air flow

Reduce/dry-up secretion

33

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

Ipratropium (Atrovent) and Tiotropium (Spiriva)

given as inhaler or nebulizer --> bronchodilation

34

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

Asthma

COPD

35

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

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

36

What are the effects of antimuscarinics on the GI tract?

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

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

reduce gastrointestinal secretions

37

What are some therapeutic uses of atropine in GI disorders?

reducing GI secretions (BUT NOT ACID IN STOMACHE)

treat diarrhea

38

What is Lomotil and what is it used for?

Diphenoxylate + atropine

slow down gut motility --> treat somache bugs

39

What are the effects of Antimuscarinics on the GU tract?

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

40

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

can worsen or causes urinary retention

41

What are some therapeutic uses of anticholinergics in urinary disorders?

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

**incontinence**

42

What is the classic anticholinergic used to treat urinary disorders?

Oxybutinin

43

How would you treat muscarinic toxicity?

anticholinergics!

Atropine

2-PAM (pralidoxime)

44

How would you most likely get mushroom poisoning?

Eating wild mushrooms --> contain natural cholinergic agents

45

What are the 2 types of mushroom poisoning?

Rapid onset

Delayed onset

46

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

Occurs w/ in 15 - 30 minutes after ingestion

muscarinic side effects

treat w/ atropine

47

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

Occurs 6 - 12 hours after ingestions

muscarinic side effects + renal/hepatic toxicity

treat w/ supportive care (atropine = ineffective)

48

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

eccrine hyperhidrosis

49

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

Glycopyrrolate

50

What are some adverse side effects of anticholinergics?

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

What are some drugs that produce anticholinergic side effects?

TCAs

Antihistamines

Phenothiazine antipsychotics

52

What are 3 contraindications of anticholinergic use?

Gluacoma (especially narrow angle)

Elderly men with BPH (benign prostatic hyperplasia)

Gastric Ulcers

53

Why would glaucoma be a contraindication for anticholinergics?

anticholinergics cause angle closure --> prevent outflow of aqueous humor

54

Why is BPH a contraindication for anticholinergics?

can worsen or causes urinary retention

55

Why are gastric ulcers a contraindication for anticholinergics?

anticholinergics --> slowed gastric emptying --> aggregate ulcer symptoms

56

What does the toxin from clostridium botulinum do?

targets presynaptic proteins that block release of ACh

57

What is the result of the toxin from clostridium botulinum?

paralysis of skeletal muscle

decreased activity @ parasympathetic and sympathetic synapses

inhibition can last weeks --> months

58

What is the toxin from clostridium botulinum used to treat?

blepharospasm

other focal muscle spasms

hyperhidrosis of palsm/axillae

cosmetic removal of wrinkles

59

What do ganglionic blocking agents do?

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

60

What is another name for ganglionic blocking agents?

Nondepolarizing competitive antagonists

61

What are some ganglionic blocking agents?

Tetraethylammonium (TEA)

Hexamethonium (C6)

Mecamylamine

Trimethaphan

62

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

Mixed sympathetic/parasympathetic effects

63

What are some of the CNS effects of ganglionic blockers?

Sedation

Tremor

Choreiform movements

Mental aberrations

64

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

Cycloplegia = Loss of accommodation

Moderate dilation of pupil

65

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

Tachycardia

66

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

decrease secretions

decrease motility

67

What are the therapeutic uses of ganglionic blockers?

Really only used in pharmacological research

68

What do neuromuscular blockers do?

@ synapse

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

69

What are the 2 groups of neuromuscular blockers?

Nondepolarizing (antagonists)

Depolarizing (agonists)

70

What do non depolarizing neuromuscular blockers do?

block ACh from binding nicotinic receptors

prevent depolarization of muscle fibers and inhibit contraction

result in very relaxed (paralyzed) muscle

71

Do nondepolarizing neuromuscular blockers bind competitively or noncompetitivelly?

competitively

72

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

AChE inhibitors

will increase ACh and overcome the competition for blocked receptors

73

When are non depolarizing neuromuscular blockers used?

during surgery --> muscle paralysis (relaxation)

ICU

74

How do non depolarizing neuromuscular blockers differ from each other?

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

75

What is a classic example of depolarizing neuromuscular blocker?

Succinylcholine

76

What does depolarizing neuromuscular blockers do?

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

What are 2 advantages of depolarizing neuromuscular blockers?

rapid onset

short duration of action

**give same effect as non polarizing antagonist**

78

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

Facilitate intubation

electroconvulsive shock therapy