Cholinolytics
Terms
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- What are cholinolytic agents?
- Block cholinergic transmission
- Muscarinic antagonists agents
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Atropine
Scopolamine
Tropicamide
Cyclopentolate
Ipratropium bromide
Tiotropium bromide
Tolterodine
Oxybutynin
Darifenacin
Solifenacin
Dicyclomine
Hyoscyamine - Muscarinic antagonists MOA
- competitive, reversible muscarinic blocker
- What is the order of blockade of MOA?
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Salivary, bronchial, sweat glands
Iris, ciliary muscle, heart
Bladder, gut
gastric acid secretion - What is the problem in using M antagonists to treat ulcers?
- Need high concentrations and too many side effects
- What are the therapeutic uses of muscarinic antagonists?
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Mydriasis
Cycloplegia
Acute rhinitis
Asthma/COPD
Preanesthetic medication
Sedative/amnesia effects
Hyperactive carotid sinus
Vagal induced heart block
Ulcers
Irritable bowel syndrome
GI spasm
parathion/mushroom poisoning
motion sickness
urinary incontinence - What other drugs can cause mydriasis?
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Alpha 1 agonists
Phenylephrine - What agents are used for mydriasis and cycloplegia?
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Tropicamide--short
Atropine--long
Scopolamine--long - How does a muscarinic antagonist work on acute rhinitis?
- Atropine blocks M receptor on nasopharyngeal glands --> decreased secretion in the respiratory tract
- What is the advantage of using ipratropium bromide as opposed to atropine?
- Less systemic absorption and less side effects
- What muscarinic antagonist agents are used for asthma/COPD?
-
Ipratropium bromide--short DOA
Tiotropium bromide--long DOA - How does a muscarinic antagonist work on the lungs for asthma/COPD?
- Ipratropium blocks M on lung --> bronchodilation
- Why is advantageous for ipratropium bromide use in COPD?
- An increase in cholinergic tone is a major reversible component in COPD and usually less side effects than beta agonists.
- Why use a muscarinic antagonists prior to general anesthesia?
- Atropine --> less secretions in respiratory tract
- What can a therapeutic dose of scopolamine do?
- CNS depression, depression, amnesia, fatigue, and dreamless sleep
- Atroprine has no effect on ventricuar arrhythmias. Why?
- Few M receptors in the ventricles.
- What muscarnic agents are used for IBS?
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Dicyclomine
Hyoscyamine - Why would you add a subtherapeutic dose of atropine to an opiod antiadiarrhea medication?
- Prevent drug abuse
- Will Atropine treat most of the symptoms of poisoning by inocybe mushrooms?
- Yes
- Will Atropine treat most of the symptoms of poisoning by parathion?
- No...will need 2-PAM to block the nicotinic receptors
- How does scopolamine used in motion sickness?
- Vestibular apparatus (in inner ear) --> scopolamine --> M receptor --> blocks vomit center in medulla --> prevent motion sickness
- What muscarinic antagonists are used for urinary incontinence?
-
Tolterodine
Oxybutynin chloride
Darifenancin
Solifenacin
Trospium chloride - How does muscarinic antagonists work for urinary incontinence?
- Rem: ACh on M (detrusor muscle-contracts) and ACh on M (trigone muscle-relax) --> micturation --> block M receptors --> decrease urinary frequency
- What are the CNS adverse effects of muscarinic antagonists?
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Sedation or excitement
Disorientation, memory disturbances, dizziness, restlessness, hallucinations, delirium, and confusion - CNS effects in muscarinics...
- Scopolamine > Atroprine >>>> Ipratroprium
- Muscarinic antagonist contraindications
- NAG
- Effects of nicotine?
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--Stimulation is followed by depression
--Increase in HR/BP
--NVD
--Stimulation and tremors - Ganglionic blocker agents
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Trimethaphan
Mecamylamine - What is the MOA of ganglionic blockers?
- nicotinic receptor antagonists
- What is the clinical use of ganglionic blockers?
- Obsolete--Mecamylamine was d/c then reintroduced --> nicotine withdrawl and Tourette's