Test #1: Ch. 14 Flashcards
cholinergic drugs block actions of _________
acetcholine
muscarinic agonists represented by
bethanechol
muscarinic antagonist represented by
atropine
ganglionic stimulating agent represented by
nicotine
ganglionic blocking agents are represented by
mecamylamine
neuromuscular blocking agents represented by
d-tubocurarine and succinylcholine
cholinesterase inhibitors represented by
neostigmine and physostigmine.
bethanechol (p116)
embodies the properties that typify all muscarinic agonists and will serve as our prototype for the group.
principle structures affected by muscarinic activation are (4)
1) heart
2) exocrine glands
3) smooth muscles
4) eyes
muscarinic agonist act on the heart to cause
bradycardia
muscarinic agonist act on the exocrine glands to
increase sweating, salivation, bronichial secretions, and secretion of gastric acid.
bethanechol is approved only for _________
urinary retention, by relaxing the trigone and sphincter muscles and increasing voiding pressure.
bethanechol has been used on an investigational basis to treat _________
gastroesophogeal reflux
why is bethanechol contraindicated for patients with low bp or low CO?
because it can cause hypotension (secondary to vasodilation) and bradycardia.
adverse effects of bethanechol
1) hypotension and bradycardia
2) excessive salivation and increased gastric acid
3) increase pressure within the urinary tract
4) exacerbation of asthma by bronchoconstriction
5) dysrhythmias in hyperthyroid pts (increasing HR–which is an opposite effect p117)
Cevimeline [Evoxac]
derivative of acetylcholine witha ctions much like those of bethanechol. Indicated for xerostomia (dry mouth).
Pilocarpine
muscarinic agonist used mainly for topical therapy of glaucoma. Also used to treat dry mouth resulting from Sjogren’s syndrome
What is the clinical use of Acetylcholine?
used to produce rapid miosis (pupil constriction) following lens delivery in cataract sx.
What is found in certain poisonous mushrooms?
Muscarine
What is a selective muscarinic blocking agent?
atropine
best-known muscarinic antagonist
atropine
atropine _____ the heart
increases
atropine ______ secretion from salivary glands, bronchial glands, sweat glands and the acid secreting cells of the stomach.
decrease
atropine causes ______ of the bronchi
relaxation
atropine causes blockade of muscarinic receptors on the iris spincter causing __________
mydriasis (dilation of the pupil)
at therapeutic doses, atropine can cause mild central nervous system _________
excitation
at toxic doses, atropine can cause __________ & ________
hallucinations and delirium.
Adverse effects of atropine
1) xerostomia (dry mouth)
2) blurred vision & photophobia
3) elevation of intraocular pressure
4) urinary retention
5) constipation
6) anhidrosis (absence of sweat)
7) tachycardia
8) asthma
two drugs mostly used for overactive bladder (OAB)
oxybutynin & tolterodine. these drugs block muscarinic receptors elsewhere and cause the typical anticholinergic SE.
anticholinergic agent that acts primarily at M3 muscarinic receptors. approved only for OAB.
oxybutynin [ditropan XL, gelnique, oxytrol]
anticholinergic agent used for OAB, and displays the greatest degree of M3 selectivitiy. Has no affect on M1 (brain) or M2 (heart).
darifenancin [Embalex]
anticholinergic agent used for OAB and very similar to darifenancin but not as M3 selective.
solifenacin [VESIcare]
nonselective muscarinic antagonist approved only for OAB. Available in short and long acting formulations. Can produce serious cardiac dysrhythmias.
tolterodine [detrol, detrol LA]
nonselective muscarinic antagonist similar to tolterodine. both agents are used only for OAB. has not been associated with QT prolongation and does not pose a risk for dysrhythmias.
fesoterodine [toviaz]
anticholinergic drug with actions much like those of atropine, with two exceptions… 1. causes CNS sedation and 2. suppresses emesis
Scopolamine
anticholinergic drug used to treat asthma, COPD, and rhinitis caused by allergies and common cold.
Ipratropium Bromide [atrovent]
this drug is indicated for irritable bowel syndrome by IM injection
Dicyclomine [Bentyl]
centrally acting anticholinergics used to treat Parkinson’s disease and drug-induced Parkinsonism.
Cogentin and trihexyphenidyl.
what is the best antidote for muscarinic antagonist poisoning?
physostigmine, a cholinesterase inhibitor
