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Pharmacology - Foundation Module > Cholinergic Agonists > Flashcards

Cholinergic Agonists Flashcards

1
Q

Why does Ach lacks therapeutic action?

A

Multiplicity of actions (leading to diffuse effects)

Rapid inactivation by the cholinesterases

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2
Q

What are the effects of Ach on heart rate and cardiac output?

A

Low heart rate
Low cardiac output
{Due to reduction in the rate of firing at the sinoatrial (SA) node}

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3
Q

Injection of ACh causes vasodilation and lowering of blood pressure by activating ____ receptor on the endothelium.

A

M3

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4
Q

How does NO produces vasodilation?

A

M3 receptor stimulated → Arginine to NO → protein kinase G in SMCs → hyperpolarization and SMCs relax (PDE inhibition)

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5
Q

______________, a direct-acting cholinergic agonist, is used to assist in the diagnosis of asthma due to its
bronchoconstricting properties

A

Methacholine

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6
Q

In the genitourinary tract, ACh __________ (increases/decreases) the tone of the detrusor muscle, causing urination

A

increases

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7
Q

In GI tract, it __________ (enhances/inhibits) secretions and motility

A

enchances

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8
Q

In the eye, ACh is involved in stimulation of ciliary muscle contraction for _______ (far/near) vision and in the constriction of the pupillae sphincter muscle, causing _________ (miosis/mydriasis)

A

near

miosis

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9
Q

ACh (1% solution) is instilled into the __________ (anterior/posterior) chamber of the eye to produce miosis during ophthalmic surgery

A

anterior

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10
Q

_____________ lacks nicotinic actions (due to addition of the methyl group), but does have strong muscarinic activity

A

Bethanechol

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11
Q

__________ has about a 1-hour duration of action

A

bethanechol

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12
Q

bethanechol is used to _________ (stimulate/inhibit) the atonic bladder

A

stimulate

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13
Q

____________ is used for postpartum or

postoperative, nonobstructive urinary retention

A

bethanechol

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14
Q

Adverse effects of cholinergic agonists?

A 
Nausea
Diarrhea
Bronchospasm
Urinary urgency
Miosis
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15
Q

Carbachol’s intraocular use provides miosis for eye surgery and _________ (increase/decrease) intraocular pressure in the treatment of glaucoma

A

decrease

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16
Q

Which one is more potent?

Carbachol OR Pilocarpine

A

carbachol

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17
Q

___________ can penetrate into CNS (carbachol/bethanechol/pilocarpine)

A

pilocarpine

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18
Q

The drug of choice for EMERGENCY lowering of intraocular pressure of both open-angle and angle-closure glaucoma is _____________ (pilocarpine/carbachol)

A

pilocarpine

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19
Q

How does pilocarpine lowers IOP?

A

Pilocarpine is extremely effective in opening the trabecular meshwork around the Schlemm canal, causing an immediate drop in intraocular pressure because of the increased drainage of
aqueous humor.

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20
Q

Onset of action and duration of action for pilocarpine

A 
Onset = few minutes
Duration = 4 to 8 hours
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21
Q

What r agents other than pilocarpine that can be used to treat glaucoma?

A

Dorzolamide and Timolol, are effective in treating glaucoma but are not used for emergency lowering of intraocular pressure
Carbachol

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22
Q

__________ is beneficial in promoting salivation in patients with xerostomia resulting from irradiation of the head and neck

A

pilocarpine

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23
Q

___________, which is characterized by dry mouth and lack of tears, is treated with oral pilocarpine tablets and cevimeline

A

Sjögren syndrome

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24
Q

___________ can cause blurred vision, night blindness, and brow ache

A

pilocarpine

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25
Q

Poisoning with __________ is characterized by

exaggeration of various parasympathetic effects which can be counteracted by parenteral atropine

A

pilocarpine

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26
Q

The effects of pilocarpine are similar to those produced by consumption of mushrooms of the genus ________

A

Inocybe

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27
Q

Summarise the cholinergic agonists

  1. Ach
  2. Bethanechol
  3. Carbachol
  4. Pilocarpine
A
  1. Ach for miosis in ophthalamic surgery
  2. Bethanechol for tx of urinary retention
  3. Carbachol for miosis and lowering IOP for glaucoma
  4. Pilocarpine for emergency tx of glaucoma
28
Q

Excess of edrophonium can cause ___________

A

cholinergic crisis

29
Q

What is edrophonium

A

Reversible cholinesterase inhibitor

30
Q

Edrophonium is used for the diagnosis of ________________

A

myasthenia gravis

31
Q

IV injection of edrophonium rapidly ___________ (increases/decreases) the strength of the muscle which confirms the dx of myasthenia gravis

A

increases

32
Q

Edrophonium also ___________ (reverse/enhance) neuromuscular blocking effects of drugs

A

reverse

33
Q

Edrophonium is a ________ (short/intermediate) acting drug

A

short (10-20min)

34
Q

Physostigmine and neostigmine are __________ (short/intermediate) acting drugs

A

intermediate

35
Q

_____________ is contraindicated in intestinal and urinary nonobstructive retention

A

neostigmine

36
Q

WHich one of the following enters CNS?

Physostigmine or neostigmine

A

physostigmine (so it produces paralysis of skeletal muscles if given in high doses)

37
Q

Adverse effects of physostigmine

A

Convulsions and skeletal muscle paralysis

38
Q

___________ is used for the chronic management of myasthenia gravis

A

pyridostigmine

39
Q

duration of action of pyridostigmine is _________

A

3-6 hrs

40
Q

tacrine is not used for tx of AD bcz of ____________

A

hepatotoxicity

41
Q

Donepezil, rivastigmine, and galantamine all are used to delay progression only but can’t stop ___________________

A

Alzheimers disease

42
Q

_________ is used for postoperative abdominal distention and for gastric atony following bilateral vagotomy

A

Bethanechol

43
Q

parenteral (IV or IM) administration of ___________ (carbachol/bethanechol) may cause cardiac arrest

A

bethanechol

44
Q

Patients with no clinically apparent asthma are ______ (more/less) sensitive to methacholine-induced bronchoconstriction than normal patients

A

more

45
Q

When used before surgery to treat acute narrow-angle glaucoma, pilocarpine is often given in combination with an indirectly acting muscarinic agonist such as ______________

A

physostigmine

46
Q

What r the contraindications of direct acting cholinergic agonists?

A 
Peptic ulcer
Asthma
Cardiac disease
Parkinson disease
Hyperthyroidism
Mechanical obstruction of the GI or urinary tract
47
Q

Nicotine-based products and varenicline (Chantix), direct-acting nicotinic receptor agonists, are approved for use in _________ cessation

A

smoking cessation

48
Q

_________ acts as an antidote for organophosphorus insecticide and nerve gas poisoning

A

Pralidoxime

49
Q

Postoperative ileus and congenital megacolon, and urinary tract retention can be treated with direct or indirectly acting cholinomimetic drugs such as ___________ and _____________

A

bethanechol

neostigmine

50
Q

____________ are also used to increase the tone of the lower esophageal sphincter

A

Bethanechol and neostigmine

51
Q

Myasthenia gravis is an autoimmune disease in which antibodies complex with ____________ receptors at the neuromuscular junction to cause skeletal muscle
weakness and fatigue

A

nicotinic

52
Q

Adverse effects of cholinergic agonists

Mnemonic - DUMBBELS

A 
Diarrhea
Urination
Miosis
Bradycardia
Bronchorrhea
Emesis
Lacrimation
Salivation
53
Q

Myasthenia gravis can be diagnosed using the __________ test, which can also assess the adequacy of treatment with AChE inhibitors

A

Tensilon

54
Q

In tensilon test, if there is no effect, or

if muscle weakness increases, the dose of the AChE inhibitor is too ________ (high/low)

A

high

55
Q

____________ can be used following surgery to reverse neuromuscular blockade and paralysis resulting from adjunct use of nondepolarizing agents

A

Neostigmine or edrophonium

56
Q

Atropine and scopolamine poisoning that results in severe body temperature elevation or tachycardia can be treated with ____________(physostigmine/neostigmine), which reverses the central and the peripheral effects of competitive muscarinic antagonists

A

physostigmine

57
Q

Many lipid-soluble ____________ are used as insecticides or nerve gases and may be absorbed in sufficient quantities from the skin or lungs to cause cholinergic intoxication

A

organophosphates

58
Q

Examples of agents that cause cholinergic intoxication

  1. insecticides
  2. nerve gas
A

insecticide = malathion

nerve gas = sarin gas

59
Q

What is the treatment of cholinergic intoxication?

A

(1) Maintain respiration and decontaminate to prevent further absorption.
(2) Administer atropine parenterally to inhibit muscarinic effects.
(3) Administer pralidoxime within minutes of exposure.

60
Q

Choline uptake is inhibited by _____________

A

hemicholinium

61
Q

____________ interacts with synaptobrevin and other proteins to prevent ACh release

A

Botulinum toxin

62
Q

__________ is used for tx of blepharospasm, strabismus/hyperhidrosis, dystonia, and cosmetics

A

Botulinum

63
Q

What are the uses of edrophonium?

A

Dx of MG

Antidote for competetive NM blockers

64
Q

What r the uses of neostigmine?

A

tx of MG
tx of postoperative abd distention and urinary retention
antidote for competetive NM blockers

65
Q

What are the uses of physostigmine?

A

Reverses CNS effects of atropine
Reverses CNS and CVS effects of TCA
Increases bladder and intestinal motility

66
Q

Echothiophate is used in the tx of ___________ glaucoma

A

open angle

Pharmacology - Foundation Module (3 decks)

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