Cholinergic Antagonist Flashcards

Exam 4

1
Q

Nicotinic receptor antagonist

A
  • ganglionic blocking agents

- neuromuscular blocking agents

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2
Q

Muscarinic receptor antagonist

A
  • block muscarinic receptor of PSN
  • blocking PSN allows SNS to go unopposed
  • used to relax smooth muscle, decrease gland secretions, and stimulate heart
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3
Q

Ganglionic blocking agents

A
  • mecamylamine

- prevents stimulation of postsynaptic receptors by ACh released from presynaptic nerve endings

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4
Q

Neuromuscular blocking agents

A
  • bind to nicotinic receptor on skeletal muscle inhibiting neurotransmission leading to muscle weakness and paralysis
  • nondepolarizing neuromuscular blocking agents
  • depolarizing neuromuscular blocking agents
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5
Q

Nondepolarizing neuromuscular blocking agents

A
  • competitive antagonists of ACh at nicotinic receptors

- Atracurium, cistracurium, pancuronium, rocuronium, vecuronium

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6
Q

Depoarlizing neuromuscular blocking agents

A
  • binds to and continually stimulates nicotinic receptors, inhibiting neuron from further depolarization, preventing neuronal impuses
  • Succinylcholine
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7
Q

Eye muscarinic receptor antagonist

A
  • Atropine (mydriasis & bradycardia)
  • Homatropine
  • Tropicamide
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8
Q

CNS muscarinic receptor antagonist

A
  • Bentropine
  • Trihexyphenidyl
  • Scopolamine
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9
Q

GI & respiratory muscarinic receptor antagonist

A

-Glycopyrrolate (decrease mucus production)

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10
Q

GI muscarinic receptor antagonist

A
  • Hyoscyamine

- Dicyclomine

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11
Q

Respiratory muscarinic receptor antagonist

A
  • Ipratopium (asthma and COPD)

- Tiotropium

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12
Q

GU muscarinic receptor antagonist

A
  • Oxybutyinin
  • Darifenacin
  • Solifenacin
  • Tolterodine
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13
Q

MOA of muscarinic antagonist

A
  • compete with ACh for muscarinic receptors at parasympathetic junctions and inhibit nerve stimulation
  • reversible antagonist which block M1, M2, or M3 receptors depending on selectivity of the agent
  • because they are reversible blockers their effects can overcome by giving larger doses of agonist = more ACh
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14
Q

Anticholinergic effects on eye

A
  • block M3 receptors
  • pupillary constrictor muscles are inhibited (relax)
  • mydriasis & cycloplegia: paralysis of the accommodation muscle for near vision causing blurred vision
  • dry eyes (from decreased tearing)
  • clinical use: eye exams to dilate pupils & paralyze lens
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15
Q

Anticholinergic effects on CNS

A
  • agents block several muscarinic receptor subtypes
  • sedation
  • anti motion sickness action
  • anti parkinson action
  • amnesia
  • delirium
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16
Q

Anticholinergic effects of CVS

A
  • Tachycardia: blockage of M2 receptor in SA node

- Clinical use: Atropine is part of the ACLS for significant bradycardias

17
Q

Anticholingeric effects on GI tract

A
  • decreased secretions and motility of the GI tract (increase gastric emptying time and intestinal transit time = constipation)
  • clinical use: treat symptoms of diarrhea, intestinal spasms - dicylcomine (Bentyl)
18
Q

Anticholinergic effects on respiratory

A
  • bronchodilation & decrease secretions (block M3 receptor)
  • effects is more in airway or lung that is diseased than it is in the healthy lung
  • clinical use: COPD and asthma
  • Tiotropium (Spiriva)
  • Ipratropium (Atrovent)
19
Q

Anticholinergic effects on GU tract

A
  • relaxes smooth muscle of the bladder wall and slows voiding. Don’t tend to urinate as much
  • clinical use: relieve bladder spasm and help those urinating frequently due to bladder spasm (overactive bladder)
  • oxybutynin (Detrol)
20
Q

Anticholinergic effects sweat glands

A
  • antimuscarinic drugs work by blocking receptors causing decreased sweat, increased temp
  • clinical use: none, but a major source of morbidity & mortality.
  • when anticholinergic drug causes death most often does so by hyperthermia
21
Q

Cholinergic poisoning

A
  • anticholnergic is cholinerimetic poisoning, such as organophosphates, insecticides, or nerve gas
  • symptoms of cholinesterase inhibitor poisoning (DUMBBELSS)
  • Diarrhea
  • Urination
  • Miosis
  • Bronchospasm
  • Bradycardia
  • Excitation of skeletal muscle and CNS
  • Lacrimation
  • Sweating
  • Salivation
  • may lead to respiratory failure if untreated
  • Atropine blocks DUMBBELSS
22
Q

Anticholinergic toxicity

A
  • problem for children and elderly
  • increased body temp
  • dry skin
  • flushed skin
  • cycloplegia
  • disorientation
  • urinary retention
  • cause acute angle closure glaucoma in elderly
  • urinary retention in men with BPH
  • hyperthermia in infants
23
Q

Tx of anticholinergic toxicity

A
  • tx the symptoms
  • if fever use a cooling blankets and drugs that lower temp like acetaminophen
  • if tachycardic use drugs to slow heart
  • Physostigmine can be given in increase ACh (inhibits enzyme that breaks down ACh) when necessary (cholinergic agent)