Cholinergic Drugs Flashcards
what are esters of choline
direct acting choline agonists that are quaternary ammonium compounds that differ by their susceptibility to hydrolysis by cholinesterases
name the choline esters
acetycholine, carbachol, bethanechol, methacholine
which of the choline esters are more resistant to hydrolysis by cholinesterases
carbachol, bethanechol, methacholine
uses of acetycholine
for rapid miosis after delivery of lens in cataract surgery, in penetrating keratoplasy, iridectomy, and other anterior segment surgery
what receptor does bethanechol work on
it has strong muscarinic activity and little to no nicotinic activity
uses of bethanechol
acute post op and postpartum urinary retention and neurogenic atony of the urinary bladder for retention
adverse effects of bethanechol
generalized cholinergic stimulation: sweating, salivation, flushing, low BP, nausea, abdominal pain, diarrhea, bronchospasm
receptors that carbachol works on
both muscarinic and nicotinic
uses of carbachol
- miosis during surgery
- reduces intra-ocular pressure after cataract surgery (glaucoma)
receptor that methacholine works on
primarily muscarinic agonist with slight nicotonic action
uses of methacholine
diagnosis of bronchial airway hyper-reactivity in those who are not apparent asthmatics
classify all the choline esters in term of agonists to what receptors
methacholine, bethanechol, acetylcholine, and carbachol are all muscarinic agonists
exception of carbachol which is also a nicotinic agonist
what are the natural alkaloids and what receptors they work on
muscarine, arecoline, pilocarpine –> all muscarinic agonist with exception to arecoline which is also a nicotinic agonist
of all the natural alkaloids which is the only used clinically and what is its use
pilocarpine - second line agent for open angle glaucoma and for management of acute angle-closure glaucoma
adverse effects of pilocarpine
- enter brain and cause CNS disturbance
- sweating and salivation
use of nicotine
used for the cessation of smoking
what is the biggest difference between the indirect cholinergic agonists edrophonium, carbamates, and organophosphates
how long their effect last
in order of increasing effect time
edrophonium, carbamates, then organophosphates
they are all cholinesterase inhibitors hence prolonging the effect of acetylcholine
use of edrophonium
diagnosis of myasthenia gravis; used to reverse the neuromuscular block produced by non depolarizing blockers
what isn’t edrophonium used for tx of said disease and rather just for diagnosis
it is very short acting
what are the carbamates
neostigmine, physostigmine, pyridostigmine
what is the use of physostigmine
tx for overdose on anti cholinergic drugs
what is so special about physostigmine and what type of pt do you not give this drug to
it can cross the BBB
do not give to those who overdose on TCA because it can aggravate depression of cardiac conduction
adverse effects of physostigmine
- crosses CNS and can lead to convulsion if high doses are used
- bradycardia
- at NMJ, huge collection of acetycholine can lead to paralysis of skeletal muscle
uses of neostigmine
- could be used for myasthenia gravis
- reversal of effects of non depolarizing neuromuscular blockers after surgery (most common use)
- prevention and tx of post op distention and urinary retention
adverse effects of neostigmine
salivation, flushing, low BP, nausea, vomiting, diarrhea, bronchospasm
uses of pyridostigmine
treatment of myasthenia gravis (most common use)
what is echothiophate used for
chronic open angle glaucoma, subacute or chronic angle closure glaucoma, or where surgery is contraindicated
basically used for glaucoma
what are malathion and parathion
they are insecticides and are dangerous
acetylcholinesterase inhibitors
what are tabun, sarin, and soman
potent synthetic toxic agent
acetylcholinesterase inhibitors
acetylcholinesterases approved for treatment of alzheimers
donepezil, rivastigmine, and galantamine
drug used for organophosphate insecticide poisoning because it is a cholinesterase regenerator
pralidoxime
muscarinic receptor antagonist
atropine, scopolamine
actions of atropine
eyes - mydriasis, increase intraocular pressure dangerously in those with glaucoma
GI - reduces motility
Urinary - decreases hypermotility of bladder
cardiovascular - blockade of M2 receptors and tachycardia
salivary, sweat, and lacrimal glands blocked
increase in body temp since sweat glands are blocked
what is atropine used for
- antisialogogue (reduce saliva production)
- increase heart rate or decrease AV block
- antidote for amanita muscaria
- antidote for overdose on cholinergic drugs
- alleviate side effects of muscarinic side effects of anticholinesterase drugs
adverse effects of atropine
dry mouth, blurred vision, sandy eyes (dry eyes), tachycardia, restlessness, confusion, hallucinations, delirium, depression, exacerbate an attack of glaucoma
difference between atropine and scopolamine
scopolamine has greater action in CNS and longer duration of effects
uses of scopolamine
mydriasis and cycloplegia (for diagnostic procedures)
prevent nausea and vomiting in motion sickness
iridocyclitis
adverse effect of scopolamine
blocks short term memory
sedation
