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Renal II > Cholinergic agents > Flashcards

Cholinergic agents Flashcards

1
Q

Choline Esters

A

ACh, carbachol, bethanechol
quartenary ammonium groups= poor abs and distribution to CNS
hydrolyzed in GI= less active when given PO
ACh>Methacholine>carbachol=bethanechol (speed of hydrolyzation by AChE)

cholinergic agonists

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2
Q

Alkaloids

A

Muscarinic, nicotine, pilocarpine
uncharged, well absorbed (nicotine patch thru skin)
muscarine is neurotoxin (from mushrooms)

acidification of urine increases clearance

cholinergic agonists

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3
Q

Nicotinic stimulant toxicity

A

CNS: alerting in low doses, tremor, emesis, stimulation or resp. center, convulsion, coma at high dose

peripherally activates both PSNS and SNS
CNS= SNS ( HTN with alternating tachy and brady)
GI/GU= PSNS: N/V/D/urination

tx=atropine for exs PSNS activity and anticonvulsants (diazepam)
Neuromuscular blockade is not responsive to treatment

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4
Q

Cholinergic functions in CNS

A

mostly M in Brain, N in the spinal cord
increased cognitive function (memory learning)

tremors hypothermia, seizures, analgesia

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5
Q

Clinical uses of direct acting cholinergic agonists

A

1) Glaucoma (contracts ciliary mm.) opens angle
2) accomodiative esotropia (congenital far-sighted induced strabismus)
3) Post-op Ileus, Congenital megacolon, urinary retention, GERD (contracts LES)
4) Salivary secretion in Sjogrens

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6
Q

Contraindications of muscarinic agonists

A

asthma, hyperthyroidism, coronary insufficiency, acid-peptic disease

OD cause SLUDGE sx (tx= atropine)

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7
Q

ACh

A

Choline ester
rarely used systemically
intraocular drops during surgery –>miosis

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8
Q

Methacholine

A

Choline ester

inhalation for dx of bronchial airway hyperreactivity

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9
Q

Bethanechol

A 
Choline ester 
selective mAChR agonist 
ex for urinary retention and heartburn 
little CV stimulation 
risk for UTI
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10
Q

carbachol

A

Choline ester
nonspecific cholinergic agonist
tx for glaucoma or miosis during surgery or examination

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11
Q

Pilocarpine

A

Alkaloid
pure mAChR agonist
xerostomia (PO), miosis during surgery (topical) glaucoma (topical)

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12
Q

Varenicline

A

(chantix)
smoking cessation
PARTIAL nAChR agonist (just at lower levels than nicotine)
stimulates DA from mesolimbic system to decrease craving and withdrawal

s/e: Nausea, changes in behavior, depression, suicidal ideation

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13
Q

uses of indirect-acting cholinergics

A

1) Glaucoma
2) dementia and alzheimer (corrects cholinergic neuron deficit)
3) antidote to anticholinergic poisoning (from antihistamines, atropine OD etc)
4) reversal of neuromuscular paralysis ( post-surgical)
5) myasthenia gravis

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14
Q

Duration of AChE

A

alcohols (edrophonium) are short lived
Carbamic acids 30min-6h
Organophosphates are very long lived d/t stable enzyme interaction (if enzyme aging occurs thru breaking of oxygen phos bonds, then complex is even more stable)

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15
Q

Neostigmine

A

quaternary carbamate AChE inhibitor
preferred for reversal of pharmacologic paralysis
has some direct action on N receptors on NMJ

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16
Q

Physostigmine

A

Tertiary carbamic acid AChE inhibitor
preferred antidote for anti-cholinergic poisoning (from atropine, antihistamines, sleep-aids etc)

Uncharged molecule, therefore it can cross into the CNS and correct neurological sx

17
Q

AChE inhibitors interactions

A

1) neuromuscular blocking agents ( decreased blockage)
2) succinycholine
3) AChR agonists (enhanced effects)
4) Beta blockers (enhanced bradycardia)
5) Corticosteroids (enhanced mm. weakness in ME pt)

18
Q

AChE toxicity

A

Acute: SLUDGE (salivation lacrimation, urination, diarrhea, miosis)
GI sx occur earliest after ingestion
percutaneous–>seating, mm ataxia, fasciculations

death d/t respiratory failure

19
Q

Pralidoxime

A

Cholinesterase reactivators
removes phosphorus group from AChE-organophosphate complex
restores AChE, and restores normal response at NMJ within minutes
must be given before aging has occurred
charged, so it can only correct the NMJ
given with Atropine after AChE poisoning

20
Q

Atropine-chemistry and metabolism

A

tertiary amine alkaloid
readily absorbed and distributed
half life of 2h, 60% is excreted unchanged
physiological effects in the eyes last longest

21
Q

Atropine MOA

A

reversible antagonist of mAChR (non-selective)
most selective for salivary, bronchial, and sweat glands
gastric glands least sensitive

decreased salivation and micturition are seen first

22
Q

Cholinergic antagonists -CNS

A

sedative effect at higher doses
reduced Parkinson tremor
scopolamine- drowsiness, altered mental status
and reduced vestibular disturbances

23
Q

Cholinergic antagonists- eye

A

mydriasis
cycloplegia (inability to accommodate d/t weakened ciliary mm)
reduced lacrimation

24
Q

Cholinergic antagonists- CV

A

little effect on BP or HR in normals
prevents CV effect of muscarinic agonists
low doses cause bradycardia
high doses cause tachycardia

25
Q

Cholinergic antagonists-Respiratory system

A

bronchodilation and reduced secretion
useful for surgical procedures
also to treat COPD and asthma

26
Q

Cholinergic antagonists-GI

A

decreased salivation (xerostomia)
decreased gastric secretion at HIGH DOSE
NO effect on pancreatic secretions
increased intestinal transit time and slowed gastric emptying

27
Q

Cholinergic antagonists-GU

A

relax smooth mm of ureters and bladder wall, slows voiding

28
Q

Cholinergic antagonists-sweat glands

A

anhidrosis

can cause atropine fever in children and adults (high dose)

29
Q

drugs that reduce movement disorders

A 
mAChR antagonists reduce PD tremors 
benztropine
orphenadrine
procyclidine 
trihexyphenidyl
30
Q

Scopolamine

A

mAChR antagonist
used to treat sea sickness (reduces vestibular disturbances)
Injection, PO, or Transdermal (post-auricular)

31
Q

ipratropium

A

mAChR antagonist
first-line inhalation therapy for asthma and COPD (d/t bronchodilation)
short t1/2 q.i.d.
charged molecule, so not absorbed systemically (good)

32
Q

Tiotropium

A

mAChR antagonists
longer bronchodilator action compared to ipratropium d/t longer t1/2
can be taken QD

33
Q

oxybutynin

A

selective M3 antagonist , prototypical drug used to reduce urinary frequency
s/e: xerostomia, dizziness, constipation, blurred vision

34
Q

trospium

A

selective M3 antagonist, similar to oxybutynin for urinary frequency

35
Q

darifenacin
solifenacin
tolterodine

A

selective M3 antagonist , prototypical drug used to reduce urinary frequency
better d/t reduced xerostomia and constipation
longer t1/2

36
Q

contraindications of AChR antagonists

A

glaucoma
prostatic hyperplasia (risk for acute urinary retention)
acid-peptic disease (d/t slowed gastric emptying time, which would increase discomfort)

37
Q

Mecamylamine MOA

A

ganglion-blocker: competitively blocks ACh on nAChR at PSNS and SNS ganglia (BLOCK ALL autonomic output)
Charged, can enter CNS

**bc PSNS usually predominates, results in enhanced SNS activity (except in vasculature

38
Q

Mecamylamine organ effects

A

CNS- sedation, tremor, chorea
eye- cycloplegia, moderate dilation
CV-decreased vascular tone, decreased BP, decreased contractility, moderate tachycardia
GI-reduced secretion and motility
GU: urinary hesitancy or retention in men with BPH
inhibited erection and ejaculation

39
Q

clinical use of mecamylamine

A

HTN and smoking cessation

Renal II (7 decks)

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