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Cholinergic Antagonists - Coggle Diagram
Cholinergic Antagonists
muscarinic cholinergic antagonists
belladonna alkaloids
atropine and scopolamine
tertiary amine
can cross c memb
wide distrib
can cross BBB
excre in urine
herbi less sensi to orally-admin atropine
L-hyoscyamine
synthetic drugs
quarternary amine based
Ex: glycopyrrolate
excre unchanged in urine and feces
poor oral bioavail
no CNS penetration
some may undergo metab
tertiary amine based
Ex: tropicamide
can cross BBB
often used topically
effects
respir
dec respir secre
bronchodila
GI and GU tract
urinary bladder relaxation
causes urine retention
dec saliv
anti-diarrheal: dec smooth musc spasms and GI secre
cardiovascu
AV conduc
inc HR
sweat gl
dec perspira = elev body temp
eye
cycloplegia: loss of accom due to inhib of ciliary musc contrac
mydriasis: pupillary dila
dec tear produc
brain
sedation
delirium and seizures at high doses
antidote for anti-cholinesterase poisoning/cholinergic toxidrome
anti-cholinergic toxidrome
blind as a bat
(mydriasis and cycloplegia),
red as a beet
(vasodil),
mad as a hatter
(delirium),
dry as a bone
(dry skin/mm),
hot as a desert
(hyperthermia),
stuffed as a pipe
(urinary and bowel retention)
antidote: carbamate cholinesterase inhibitor (neostigmine)
competitive nicotinic cholinergic antagonists
ganglionic blockers
acts as postganglionic neurons
hexamethonium
antag at neural AChRs
inhib sympa neurotransm
dec cardiac contractil
vasodil and hypotension
dec stress assoc sweating
inhib parasympa neurotransm
tachycardia
mydriasis and cycloplegia
urine retention and constipation
dry mouth
non-depolarizing neuromusc blockers
acts at neuromusc junc (NMJ)
prevents ACh from depolariz musc c = causes paralysis
has NO effect on abil to conduct action potentials
DOES NOT REDUCE PAIN SENSA - just reduces abil to respond to it
lim Vd and doesn't cross BBB
musc paralysis seq
tail and jaw
neck and distal limb musc
prox limb musc
swallowing and phonatory musc
abd wall musc
intercostal musc
diaphragmatic musc
respir paralysis expected
reversed by excess ACh (cholinesterase inhib)
pancuronium
onset: 5 min, duration: 40-60 min
renal excre
blocks mAChRs and nAChRs
side effects
tachycardia, histamine release, vasodila, hypotension
vecuronium
onset: 5 min, duration: 30 min
fewer cardiovascu side effects
biliary excre
atracurium
onset: 5 min, duration: 30 min
spont decomposes in plasms
fewer cardiovascu side effects
poten hypotensive at high doses if histamine is released
cis-atracurium
basically atracurium w/o poss of histamine release