Cholinomimetic agents

Question 1

Bethanechol: clinical use, action

Answer 1

Clinical use: Postoperative ileus, neurogenic ileus, urinary retention
Action: Cholinergic direct agonists.
Activates bowel and bladder smooth muscle; resistant to AChE

Question 2

Carbachol: clinical use, action

Answer 2

Clinical use: Constricts pupil and relieves intraocular pressure in glaucoma
Action: Cholinergic direct agonists
~acetylcholine
“Garbachol treats glaucoma, and constricts pupils”

Question 3

Methacholine: clinical use, action

Answer 3

Clinical use: Challenge test for asthma
Action: Cholinergic direct agonists.
Stimulates muscarinic receptors in airway when inhaled

Question 4

Pilocarpine: clinical use, action

Answer 4

Clinical use: Potent stimulator of sweat, tears, and saliva. Open-angle and closed angle glaucoma
Action: Cholinergic direct agonists.
Contrasts ciliary muscle of eye (open angle), pupillary sphincter (closed angle), resistant to AChE

Question 5

Donepezil, galantamine, rivastigmine: clinical use, action

Answer 5

Clinical use: Alzheimer Disease
Action: Indirect agonists (anticholinesterases)
Increases ACh

Question 6

Edrophonium: clinical use, action

Answer 6

Clinical use: to dx M.G. (short acting) in the past
Now M.G. dx with anti-AChR Ab
Action: Indirect agonists (anticholinesterases)
Increases ACh

Question 7

Neostigmine: clinical use, action

Answer 7

Clinical use: Postoperative and neurogenic ileus and urinary retention, M.G. reversal of NMJ bloackade (postop)
Action: Indirect agonists (anticholinesterases)
Increases ACh, No CNS penetration

Question 8

Physostigmine: clinical use, action

Answer 8

Clinical use: Anticholinergic toxicity; crosses BBB
Action: Indirect agonists (anticholinesterases)
Increases ACh
Used for atropine overdose (Jimson weed contact)

Question 9

Pyridostigmine: clinical use, action

Answer 9

Clinical use: to dx M.G. (long acting)
Does not penetrate the CNS
Action: Increases ACh; increases muscle strength
*pyRIDostGMine-gets rid of MG”

Question 10

What should you watch for with cholinomimetic agents?

Answer 10

Exacerbation of COPD, asthma, peptic ulcers (in susceptible patients)

Question 11

Cholinesterase inhibitor poisoning

Answer 11

Organophosphates, often seen in farmers
Antidote: atropine (competitive inhibitor) + pralidoxime (regenerates AChE if given early)
Symptoms: Diarrhea, uriniation, miosis, bronchospasm, bradycardia, excitation of Sk. mm and CNS, lacrimation, sweating, salivation