Cholinomimetic Agents Flashcards
What are the direct cholinomimetics? (4)
What do they do?
Bethanechol
Carbachol
Pilocarpine
Methacholine
They act like acetylcholine
Bethanechol
MOA
Use
Activates bowel and bladder smooth muscle, RESISTANT TO ACHE
Use for to get rid of these:
Postop and neurogenic Ileus
Urinary Retention
Carbachol
MOA
Use
“Carbon copy of Ach”
Use to get rid of this:
Glaucoma
Pupillary Constriction
Reduce IOP
Pilocarpine
MOA
Use
MOA:
Contracts ciliary m in open angle glaucoma
Activates pupillary sphincter in close angle
Resistant to ACHE
Uses:
Potent stimulator of sweat, tears, and saliva
Open and closed angle glaucoma
CF Sweat challenge test
Methacholine
MOA
Use
MOA
Stim muscarinic receptors in airway when inhaled
Challenge test for asthma at small doses, but METAB BY ACHE
What are the indirect cholinomimetic agonists, aka ANTICHOLINESTERASES? (7)
Neostigmine Pyridostigmine Physostigmine Donepezil, Rivastigmine, Galantamine (Alzheimers) Edrophonium
Neostigmine:
MOA
Use
Increases endogenous Ach
Neo CNS…No CNS penetration (if too much given, then flaccid paralysis and desensitization)
Uses: Postop and neur ileus Urinary Retention MG Reversal of NMJ blockade
Pyridostigmine
MOA
Use:
Increase endogenous Ach
PyRIDostiGMine gets RID of MG by kicking Abs off the receptor
Uses:
MG (long acting) but doesn’t penetrate CNS
4 amine
Physostigmine
MOA
Uses
Increase endog Ach
PHYsostigmine PHYxes ATROPINE overdose
Use:
For Anticholinergic toxicity (can X BBB bc so can atropine )
Donepezil, Rivastigmine, Galantamine, Tacrine
MOA
Uses
Increase endogenous Ach
Oral / Lipid Soluble
Uses:
Alzheimers
Edrophonium
MOA
Uses:
Increases endogenous Ach
Use:
Used to be for the Dx of MG bc short acting. Now MG is dx’d by Anti-AChR Ab test
When using Edrophonium to Dx MG how can you tell its MG?
If muscle tone increases with edrophonium, then its MG and then treat with Neostigmine or Pyridostigmine.
If it doesn’t then its cholinergic crisis
What kind of patients should be monitored when treating with cholinomimetic agents?
Those with secretion probs:
COPD
Asthma
Peptic Ulcers
What are the signs of cholinesterase inhibitor poisoning?
What is it usually due to?
What is the antidote?
Often due to organophosphates i.e. parathion
They IRREVERSIBLY inhibit AChE (think noncompetitive inhibitor)
DUMBBELLS Diarrhea Urination Miosis Bronchospasm Bradycardia Excitation of skeletal muscle and CNS Lacrimation Sweating Salivation
Antidote: Atropine (competitive inhibitor) with Pralidoxome (regenerates AchE if given early enough
