Exam II: Cholinergic Antagonists Flashcards

1
Q

What are the two groups of anticholinergics? (Cholinergic antagonists)

A
  1. Muscarinic

2. Nicotinic

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2
Q

What are muscarinic antagonists also called?

A

Parasympatholytic or antimuscarinic

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3
Q

An example of a parasympatholytic or antimuscarinic is…

A

Atropine

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4
Q

Describe the actions of atropine

A
  1. Reversibly block muscarinic receptors

2. Typically block actions of exogenously administered cholinergics > endogenous acetylcholine

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5
Q

What tissues are most sensitive to atropine?

A

Salivary
Bronchial
Sweat Glands

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6
Q

What are the tissues effected by atropine?

A
Eye
CV System
Respiratory system
GI tract
GU tract
Sweat glands
CNS
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7
Q

Examples (3) of nicotinic anticholinergics

A
  1. Tetraethylammonium
  2. Tubocurarine
  3. Succinycholine
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8
Q

Which antimuscarinic is better to elicit CNS effects: atropine or scopolamine?

A

Scopolamine

Atropine is hydrophillic and cannot cross BBB well so it has a minimal effect

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9
Q

What does scopolamine cause at therapeutic doses? At toxic doses?

A

Therapeutic doses:

  • -> drowsiness
  • -> amnesia (if pt is sensitive)

Toxic doses:

  • -> CNS excitement
  • -> Agitation
  • -> Hallucination
  • -> Coma
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10
Q

What are two common therapeutic uses for antimuscarinic agents?

A

Treatment of Parkinson’s Disease

Treat motion sickness

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11
Q

What drug(s) are used in tx of Parkinson’s Dz

A

Benzotropine (antimuscarinic agent) along with a dopamine precursor drug (levodopa)

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12
Q

What drug(s) are used to treat motion sickness

A

Scopolamine

injected, oral, or transdermal patch

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13
Q

What effects do antimuscarinics have on the eye?

A
  1. Relax papillary constrictor –> mydriasis (dilation of eyes)
  2. Relax ciliary muscle –> cycloplegia (loss of accommodation)
  3. Reduces lacrimal secretion –> dry eyes!
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14
Q

Are antimuscarinincs indicated in patient’s w/ narrow angle galucoma?

A

NO!

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15
Q

Why would we use an antimuscarinic on the eye?

A

Useful for ophthalmologists to view the retina with the eye dilated and cycloplegia (given as drops)

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16
Q

If given a low dose (0.5 mg) of an antimuscarinic (atropine) what would you observe in the CV system?

A

Bradycardia

Low doses only block M1 receptors; M3 receptors still stimulated by ACh on SA node to create slowed HR

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17
Q

If given a medium to high dose (1-5 mg) of an antimuscarinic (atropine) what would you observe in the CV system?

A

Tachycardia

Blocks M2 receptors in SA and AV nodes, which usually slow HR

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18
Q

If given a toxic dose ( > 10 mg) of atropine what would you observe in the CV system?

A

Intraventricular conduction block that inhibits electrical pulse generation in pacemaker nodes

–> leads to death

19
Q

What are some therapeutic uses for antimuscarinics in the cardiovascular system?

A

Increase HR in pts w/ acute MI, SA or AV node dysfunction in which there is an unwanted bradycardia

20
Q

What dose level should be used to treat patients with unwanted bradycardia?

A

Moderate doses of atropine so as to block M2 receptor

21
Q

What effects do antimuscarinics have on the respiratory system?

A
  1. Cause bronchodilation

2. Reduce/dry up secretions

22
Q

What two respiratory diseases are treated with antimuscarinics. What are the two drugs used to treat these diseases?

A

COPD and Asthma

Ipratropium or tiotropium used in inhaler or nebulizer form

23
Q

What drugs are useful to dry up respiratory secretions?

A

Atropine or scopolamine

24
Q

List the effects of antimuscarinic drugs on the GI tract

A
  • Reduced motility, prolonging gastic empthying
  • Reduce salivary secretion –> xerostomia
  • Reduce GI secretions
25
Q

Therapeutic uses for GI Tract?

A
  • Treating diarrhea

mixed with diphenoxylate to create Lomotil

26
Q

What is the main effect that antimuscarinic drugs have on the GU system?

A

Reduce voiding –> by relaxation of detrusor muscle

27
Q

What are antimuscarinic drugs used to treat in the GU system?

A

Urinary incontinence

28
Q

List the common antimuscarinic drugs used to treat urinary incontinence

A
Oxybutinin 
Trospium
Darifenacin
Solifenacin
Tolterodine
  • Selective M3 receptor antagonist
29
Q

What are antimuscarinincs used for in terms of sweat gland dysfunctions?

A

Hyperhidrosis

**Not always effective though b/c of the different glands (eccrine and apocrine)

30
Q

Drug used to treat hyperhidrosis?

A

Glycopyrrolate

31
Q

How do you treat a patient with rapid onset mushroom poisoning compared to a patient with delayed onset mushroom poisoning?

A

Give atropine to rapid onset patient

Use supportive care with delayed onset (atropine won’t work)

32
Q

Name side effects of anticholinergics

A
  1. Mydriasis
  2. Agitation
  3. Hot, flushed skin
  4. Dry mouth
  5. Tachycardia
  6. Urinary retention
  7. Visual changes
  8. Constipation
33
Q

What are 3 contraindicated uses of anticholinergics?

A
  1. Patient’s w/ glaucoma
  2. Elderly men w/ hx of benign prostatic hyperplasia
  3. Pt’s w/ gastic ulcers
34
Q

Toxins from Clostridium botulinum are used to treat what 3 “conditions”

A
  1. Belpharospasm and other focal muscle spasms
  2. Hyperhidrosis of palms and axillae
  3. Cosmetic removal of wrinkles
35
Q

Ganglionic Blocking Agents block ____ at _______________.

A

ACh

nicotnic receptors at parasympathetic and sympathetic ganglia

36
Q

Are ganglionic blocking agents used as therapy? Why or why not.

A

No, they are mostly used in research since they have both parasympathetic and sympathetic effects, their outcomes are hard to predict.

37
Q

What do neuromuscular blockers do?

A

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

38
Q

________ block neuromuscular transmission between motor end plates and nicotinic receptors on skeletal muscle.

A

Neuromuscular blockers

39
Q

What are the two groups of neuromuscular blockers?

A
  1. Nondepolarizing (antagonists)

2. Depolarizing (agonists)

40
Q

Nondepolarizing neuromuscular blockers are _______ and therefore can be terminated with _______ because they increase ACh.

A
Competitive
AChE inhibitors (neostigmine)
41
Q

What are nondepolarizing neuromuscular blockers typically used for therapeutically?

A

Surgery - as adjuncts to anesthesia

42
Q

What are depolarizing neuromuscular blockers typically used for therapeutically?

A

Facilitate intubation
Electroconvulsive shock therapy

*Short duration and rapid onset

43
Q

What example does the lecture slides give of a depolarizing neuromuscular blocking agent and how does it work?

A

Succinylcholine

Provides a constant stimulation of the receptor (acting as ACh) and its continued presence prevents further depolarization and so muscle paralysis is the result