Muscarinic Receptor Blocking Drugs Flashcards

1
Q

What are muscarinic receptor blocking drugs?

A

Anticholinergic drugs

Parasympatholytics

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2
Q

What is the mechanism of action of parasympatholytics?

A

They remove PSY stimulation on effector cells — SY stimulation will dominate

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3
Q

Name the tertiary tropines?

A

Atropine
Scopolamine
Homatropine
Benztropine

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4
Q

How long is the duration of effect of atropine?

A

7-10 days

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5
Q

What are the clinical uses of atropine?

A
Antispasmodic
Anti-secretory
Antidiarrheal 
Ophthalmology (but has a long half life)
Management of AchE inhibitor OD
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6
Q

Is atropine a tertiary tropine or a quaternary?

A

Tertiary

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7
Q

Can atropine enter the CNS?

Why?

A

Yes

Because it is a tertiary tropine

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8
Q

Does atropine have central or peripheral effects?

A

Both central and peripheral effects

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9
Q

What is atropine competitive to?

A

Ach

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10
Q

What are the CNS effects of atropine?

A
Antimimetic effect 
Restlessness
Hallucinations
Epileptiform convulsions
Coma
Death
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11
Q

What are the peripheral effects of atropine?

A
Decreased secretions
Dry mouth
Decreased gastric secretion
Dry skin
Mydriasis (wide pupils)
Cyclopegia (blurred vision)
Hyperthermia
Bronchodilator
Tachycardia - TdP and V-fib 
Relaxation of abdominal smooth muscle which leads to decreased secretions in the intestine, urinary bladder, uterus and the Choledochus
Constipation 
Dysuria
Urinary retention
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12
Q

What is the treatment of acute intoxication with atropine?

A

Physostigmine

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13
Q

Why is physostigmine used in the treatment of atropine intoxication

A

Atropine is a competitive inhibitor of muscarinic receptors. The only way to overcome the effects of a competitive antagonist is to increase the concentration of the ligand for those receptors (Ach). Therefore we use an AchE inhibitor to increase the concentration of Ach at the synapse

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14
Q

What is mydriasis?

A

Dilation of the pupils

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15
Q

What is cyclopegia?

A

Loss of accommodation (blurred vision)

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16
Q

What are the clinical uses of parasympatholytics?

A
Mydriasis
Bronchial asthma 
COPD (ipratropium spray)
Bradycardia
1st degree AV blocks
Peptic ulcer
Incontinence
Diarrhoea
Abdominal cramps
Parkinson’s syndrome
Organophosphate poisoning
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17
Q

Which parasympatholytic is used to treat COPD and how is it administered?

A

Ipratropium spray

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18
Q

How long is the duration of effect of scopolamine?

A

3-7 days

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19
Q

What are the clinical uses of scopolamine?

A

Motion sickness
Post-operative nausea and vomiting
To block short term memory
‘Truth serum’

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20
Q

How is scopolamine administered to treat motion sickness?

A

Topical patch

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21
Q

Can scopolamine enter the CNS?

A

Yes because it is a tertiary tropine

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22
Q

What are the clinical uses of Homatropine?

A

Ophthalmology

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23
Q

What is the duration of effect of Homatropine?

A

1-3 days

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24
Q

Is homatropine a quaternary or tertiary tropine?

A

Tertiary

25
Q

What are the clinical uses of Benztropine?

A

Parkinson’s

Acute extrapyramidal symptoms induced by antipsychotics

26
Q

Which receptor does benztropine act on?

A

M1 receptor

27
Q

What type of drug is benztropine?

A

It is an M1 receptor antagonist

28
Q

What are the characteristics of Benztropine?

A

Lipid soluble so has CNS entry
M1 receptor antagonist
Tertiary tropine

29
Q

Name the quaternary tropines

A

Ipratropium
Tiotropium
Methylalatropine

30
Q

What receptor does tiotropium act on?

A

M3

31
Q

What type of tropine is tiotropium?

A

Quaternary tropine

32
Q

What are the clinical uses of tiotropium?

A

COPD

Bronchodilator

33
Q

How is tiotropium administered for COPD?

A

Inhalation, spray

34
Q

What are the clinical uses of Methylalatropine?

A

Peripheral use

35
Q

What type of tropine is methylalatropine?

A

Quaternary tropine.

36
Q

What receptor does Ipratropium act on?

A

M3 selective

37
Q

Which muscarinic blocking drugs selectively act on the M3 receptor?

A

Ipratropium

Tiotropium

38
Q

What is Ipratropium non-selective for?

A

It also stimulates the negative feedback receptor in the presynaptic nerve terminal (alpha 2 receptors ???? ) CHECK THIS

39
Q

Can Ipratropium enter the CNS?

Why?

A

No

It is a quaternary tropine

40
Q

What are the clinical uses of Ipratropium?

A

Asthma and COPD
Inhibition of Bronchospasm
Decreased secretions

41
Q

How is Ipratropium administered in Asthma and COPD?

A

Inhalation, spray

42
Q

Name the synthetic tropines with tertiary amines

A
Procyclidin
Biperiden
Tropicamide
Pirenzepine
Tolterodine
Oxybutynin
Solifenacine
Darifenacine
43
Q

What is the duration of effect of Pirenzepine?

A

6h (short acting)

44
Q

What is a characteristic of Tropicamide?

A

Short half-life

45
Q

Which receptor does tolterodine, oxybutynin, solifenacine, darifenacine act on?

A

M3 receptor antagonists

46
Q

What are the clinical uses tolterodine, oxybutynin, solifenacine, darifenacine act on?

A

Urinary incontinence

47
Q

Which of the synthetic tropines with tertiary amines are used in urinary incontinence?

A

Tolterodine
Oxybutynin
Solifenacine
Darifenacine

48
Q

Which of the synthetic tropines with tertiary amines are used in Parkinson disease?

Why?

A

Procyclidin
Biperiden

Because they inhabit tremors

49
Q

What is the clinical use of tropicamide?

A

Ophthalmology- causes mydriasis and cyclopegia

50
Q

How is tropicamide administered in ophthalmology?

A

Topical: eye drops

51
Q

Which synthetic tropine with tertiary amine is used for peptic ulcers?

A

Pirenzepine

52
Q

Name the synthetic tropine with quaternary amine

A

Propantheline

53
Q

What is Propantheline used for?

A

Abdominal spasms

54
Q

Which muscarinic blockers are used in Asthma?

A

Tiotropium

Ipratropium

55
Q

Which of the muscarinic antagonists are used in Parkinson’s disease?

A

Benztropine
Procyclidin
Biperiden

56
Q

Which muscarinic antagonists are used in COPD?

A

Ipratropium

Tiotropium

57
Q

Which muscarinic antagonists are used in ophthalmology?

A

Atropine
Homatropine
Tropicamide

58
Q

What is the duration of effect of Tropicamide?

A

0.25 day

59
Q

Which muscarinic antagonists has the longest duration of effect in ophthalmology?

A

Atropine