Principles: Autonomic Cholinomimetic Agents and Muscarinic Antagonists Flashcards
What is Bethanechol used for?
How does it work?
Bethanechol is used for postoperative ileus, neurogenic ileus, and urinary retention.
Direct ACh agonist, activates bowel and bladder smooth muscle; resistant to AChE.
“Bethany, call (bethanechol) me, maybe, if you want to activate your bowels and bladder”.
What is Carbachol used for?
What is its mechanism of action?
Uses: Glaucoma, induce pupillary constriction, relieve intraocular pressure.
Action: Direct ACh agonist, Carbon copy of acetylcholine. (Carbachol)
What is Pilocarpine used for?
What is its method of action?
Potent stimulator of sweat, tears, and saliva.
Open-angle and closed-angle glaucoma treatment.
Action: Direct ACh agonist. Contracts ciliary muscle of eye (open-angle glaucoma), pupillary sphincter (closed-angle glaucoma). Resistant to AChE.
“You cry, drool, and sweat on your pilow”.
What is Methacholine used for?
What is its method of action?
Use: Challenge test for diagnosis of asthma
Action: Direct ACh agonist.
Stimulate muscarinic receptors in the airway when inhaled. (Methacholine)
What is Neostigmine used for?
What is its method of action?
Postoperative and neurogenic ileus
Urinary retention, myasthenia gravis, reversal of neuromuscular junction blockade (postoperative)
Mechanism: Indirect agonist (anticholinesterase). Increase endogenous ACh.
Mnemonic: NEO CNS = No CNS penetration.
What is Pyridostigmine used for?
What is its method of action?
Myasthenia gravis (long acting); does not penetrate CNS.
Mechanism: Indirect agonist (anticholinesterase)
Increase endogenous ACh, increase strength.
“Pyridostigmine gets rid of myasthenia gravis”.
What is Physostigmine used for?
What is its method of action?
Anticholinergic toxicity antidote (crosses blood-brain barrier -> CNS)
Mechanism: Indirect agonist (anticholinesterase)
Increases endogenous ACh.
“Physostigmine “phyxes” atropine overdose”.
What are donepezil, rivastigmine, and galantamine used for?
What is their mechanism of action?
Alzheimer disease treatment.
Method of action: Indirect agonist (anticholinesterase)
Incresae endogenous ACh.
What is Edrophonium used for?
What is its mechanism of action?
Historically used for diagnosis of Myasthenia Gravis - extremely short acting drug. (Myasthenia is now diagnosed by anti-AChR Ab, or anti-acetylcholine receptor antibody test)
Mechanism of action: Increase endogenous ACh.
What are important common side effects of cholinomimetic agents?
Exacerbation of COPD, asthma, and peptic ulcers.
What are clinical signs of cholinesterase inhibitor poisoning?
What is the stereotypical culprit drug/scenario?
What is the antidote?
DUMBBELSS: Diarrhea, Urination, Miosis, Bronchospasm, Bradycardia, Excitation of skeletal muscle and CNS, Lacrimation, Sweating, and Salivation.
Organophosphates from insecticides - poisoning usually seen in farmers.
Antidote: Atropine (competitive inhibitor) and pralidoxime (regenerate AChE if given early).
What muscarinic antagonists can be applied to the eye?
What effect does this class of drug have?
Atropine, homatropine, tropicamide.
Produce mydriasis and cyclopegia.
What class of drug is Benztropine?
What is it used for?
Muscarinic antagonist.
Parkinson disease “Park my Benz”.
What class of drug is Scopolamine?
What is it used for?
Muscarinic antagonist.
Motion sickness.
What are the muscarinic antagonists Ipratropium and tiotropium used for?
COPD, asthma.
“I pray I can breathe soon” - Ipratropium
