L 16-17 Flashcards
Non-selective, direct acting cholinergic agonists
Acetylcholine
Methacholine, Carbachol
Selective, direct acting cholinergic agonists
Bethanechol, Pilocarpine
selective for Muscarinic
Effect of Ach IV infusion
Acts on M3 receptors to cause inc NO–> inc cGMP –> vasodilation
Choline Esters
Resist AchE better than Ach
Methacholine, Carbachol, Bethanechol
Alkaloids
Like Muscarine
Pilocarpine, Nicotine
Drug to increase GI activity
Bethanechol
Drug to increase salivation
Pilocarpine
Drug to help increase bladder function
Bethanechol
Drug to increase lacrimation, salivation, sweat etc.
Pilocarpine
Best drug for dry mouth
Pilocarpine can be used, but has side effects from stimulating all M receptors
Cevimeline: better because M3 specific
Nicotine overdose
Nicotine goes to the brain quickly and causes CNS problems
Cardiac will first beat faster causing hypertension and arrhythmias before causing hypotension
Nicotinic receptors desensitize quickly and lead to paralysis
Treat with Atropine to block M receptors and decrease PS response
Varenicline
Partial N agonist
Used to decrease cravings from nicotine withdrawal
Side effects: flatulence, psychosis. vomiting
What are drugs that end in -stigmine or -onium?
Cholinesterase inhibitors
Acetylcholine
Non-selective cholinergic agonist
Bethanechol
M-selective cholinergic agonist
In choline ester group
Used for GI and Bladder problems
Carbachol
Non-selective cholinergic agonist
Choline ester group
Pilocarpine
M-selective cholinergic agonist
used in eye, and for glands
Alkaloid
Methacholine
Non-selective cholinergic agonist
Choline ester
Neostigmine
Cholinesterase inhibitor Cleaved by AchE, then occupies site Duration 2-4hr No CNS Poor oral absorption Use: inc bladder function, Myasthenia Gravis, reverse N.M. blockade in surgery
Physostigmine
Cholinesterase inhibitor
Crosses CNS–>side effects
Only good for Atropine overdose
Pyridostigmine
Cholinesterase inhibitor
Longer duration 4-6hr
Edrophonium
Cholinesterase inhibitor
Short duration 5-20 min
Injection only, no CNS
Use: diagnose Myasthenia Gravis
Organophosphates
Cholinesterase inhibitor
Lipid soluble–>storage and slow release
Becomes irreversible with aging
Pralidoxime (2-PAM)
Prevents aging of organophosphates
Doesn’t work with carbamates
No CNS
Can itself bind AchE so must only be used in correct amount
General Effects of AchE Inhibitors
In general, Parasympathetic effects dominate
Donepezil
Cholinesterase inhibitor
Used for Alzheimers because some inc in PS activity causes inc alertness and better memory
Has long duration and low peripheral effects
Echothiophate
Organophosphate but not lipid soluble
Used in eye, effects last for days because not well absorbed
Symptoms of AchE Toxicity
High Ach=> high Parasymp. effects including SLUDGE
Neuromuscular effects => desensitization and paralysis
Muscarinic agonist has no muscle effect
Treatment: Atropine, 2-PAM
If carbamate: atropine only, no 2-PAM
