Pharm - Autonomic Drugs (Cholinomimetic agents & Cholinesterase inhibitor poisoning) Flashcards
Pg. 246 in First Aid 2014 Sections include: -Cholinomimetic agents -Cholinesterase inhibitor poisoning
Name 4 direct cholinomimetic agonists.
(1) Bethanechol (2) Carbachol (3) Pilocarpine (4) Methacoline
What are 3 clinical applications for Bethanechol?
(1) Postoperative ileus, (2) Neurogenic ileus, and (3) Urinary retention
What is the action of Bethanechol?
Activates bowel and bladder smooth muscle; Think: “BETHANy, CALL (bethanechol) me, maybe, if you want to activate your Bowels and Bladder.”
What effect does AChE have on Bethanechol?
Resistant to AChE
What are 3 clinical applications for Carbachol?
(1) Glaucoma, (2) Pupillary constriction, and (3) Relief of intraocular pressure
What is the action of Carbachol?
“CARBon copy of AcetylCHOLine”
What are 2 categories of clinical use for Pilocarpine?
(1) Potent stimulator of sweat, tears, and saliva (2) Open-angle and Close-angle glaucoma; Think: “you cry, drool, and sweat on your ‘PILOw’”
What are the 2 actions of Pilocarpine, and to which clinical applications is each related?
(1) Contracts ciliary muscle of eye (open-angle glaucoma), (2) Pupillary sphincter (closed-angle glaucoma)
What is the clinical use for Methacholine?
Challenge test for diagnosis of asthma
What is the action of Methacholine?
Stimulates Muscarinic receptors in airway when inhaled
What is another name for indirect cholinomimetic agonists? List 5 examples.
Indirect cholinomimetic agonist (anticholinesterases); (1) Neostigmine (2) Pyridostigmine (3) Physostigmine (4) Donepezil, Rivastigmine, Galantamine (5) Edrophonium
What are 4 clinical uses for Neostigmine?
(1) Postoperative and neurogenic ileus and (2) Urinary retention, (3) Myasthenia gravis, (4) Reversal of neuromuscular junction blockade (postoperative)
What is the action of Neostigmine?
Increase endogenous ACh
Does Neostigmine penetrate the CNS?
No CNS penetration; Think: “NEO CNS”
What is a clinical application for Pyridostigmine?
Myasthenia gravis (long acting); Think: “pyRIDostiGMine gets RID of Myasthenia Gravis”
Does Pyridostigmine penetrate the CNS?
Deos not penetrate CNS
What are 2 actions of Pyridostigmine?
Increase endogenous ACh; Increase strength
What is a clinical application for Physostigmine?
Anticholinergic toxicity (crosses blood-brain barrier => CNS); Think: “PHYsostigmine ‘PHYxes’ atropine overdose”
Does Physostigmine penetrate the CNS?
Crosses blood-brain barrier => CNS
What is a clinical application of Donepezil? What other 2 drugs have the same application?
Alzheimer disease; Donepezil, Rivastigmine, Galantamine
What is the action of Donepezil? Again, what other 2 drugs have this same action?
Increase endogenous ACh; Donepezil, Rivastigmine, Galantamine
What is a historical clinical application of Edrophonium? Why is it considered to be historical?
Historically, diagnosis of myasthenia gravis (extremely short acting). Myasthenia now diagnosed by anti-AChR Ab (anti-acetylcholine receptor antibody) test.
What is the action of Edrophonium?
Increase endogenous ACh
What are 3 complications that should be watched for with use of all cholinomimetic agents in susceptible patients?
With all cholinomimetic agents, watch for exacerbation of COPD, asthma, and peptic ulcers when giving to susceptible patients
What group of drugs/substances often cause cholinesterase inhibitor poisoning, and why? Give an example of such a drug.
Often due to organophosphates, such as Parathion, that irreversibly inhibit AChE
What are 9 symptoms associated with cholinesterase inhibitor poisoning?
Causes (1) Diarrhea, (2) Urination, (3) Miosis, (4) Bronchospasm, (5) Bradycardia, (6) Excitation of skeletal muscle and CNS, (7) Lacrimination, (8) Sweating, and (9) Salivation. Think: “DUMBBELSS”
In what patient population is cholinesterase inhibitor poisoning usually seen, and why?
Organophosphates are components of insecticides; poisoning usually seen in farmers
What is the antidote for cholinesterase inhibitor poisoning? Explain the mechanism of each component.
Antidote - Atropine (competitive inhibitor) + Pralidoxime (regenerates AchE if given early)
