Lecture 9: Anticholinergic Agents Flashcards
what is the primary NT of the parasympathetic nervous system?
Ach
what are the target tissue receptors of the parasympathetic nervous system?
muscarinic receptors
which muscarinic receptors are most often modified pharmacologically
M2 and M3
muscarinic antagonists cause the opposite of ____
SLUDGE
muscarionc antagonists cause what 2 changes in the eye?
pupil dilation; transient increase in IOP
heart rate can be decreased slightly during parasympathetic activation, but returns to normal quite quickly due to other ____ of the cardiovascular system
other compensatory mechanisms
in the lungs, blocking the actions of Ach promotes ____ which is a beneficial effect in asthma and COPD
bronchodilation
muscarinic receptor antagonists are typically called ____ agents
anticholinergic
what is the prototypic example of anticholinergic agent?
atropine
what are 3 beneficial applications of anticholinergic agents?
asthma, COPD, motion sickness
atropine can still be used today to treat____
cholinergic poisoning by pesticides and nerve gases
inverse agonists stabilize the ___ form of a receptor
inactive
neutral antagonists show no ___ and cause no change in ____
binding preference; basal activity
some anticholinergic agents, such as ___ have been determined to be inverse agonists of muscarinic receptors
atropine
we may expect that the effects of an inverse agonist of muscarinic receptors to be ____ than those of another anticholinergic antagonists
greater
what properties may cause the effects of inverse agonist to NOT be greater than those of anticholinergic antagonists?
level of constitutive receptor activity, the drug’s receptor affinity and concentrations reaching the target
is it clear whether inverse agonists have a clinical advantage over neutral antagonists?
no
for most therapeutic considerations, we can generalize that anticholinergic agents are ____ competitive muscarinic antagonists
non-selective
should anticholinergic agents be used locally or systemically?
locally
the use of anticholinergic agents in the treatment of asthma is achieved by delivering them in what manner?
inhaled
____ is an example of inhaled muscarinic antagonists
tiotropium
the quaternary amine of tiotropium causes the drug to be ___
charged
charged molecules do not cross the membrane easily, so when tiotropium is inhaled, it remains in the ___ where it acts without having too many adverse systemic effects
lungs
if large quantities of tiotropium are swallowed instead of inhaled we might expect to see anticholinergic effects in the ____ as we’ll
GI system
along with bronchodilation, anticholinergics also do what to contribute to clearing airways?
decreased mucus secretions
the use of anticholinergic agents in the treatment of asthma is achieved by delivering them in what manner?
inhaled
tropic amide eyedrops have a ____ duration and are often used for what procedure?
short; eye examinations
the quaternary amine of tiotropium causes the drug to be ___
charged
charged molecules do not cross the membrane easily, so when tiotropium is inhaled, it remains in the ___ where it acts without having too many adverse systemic effects
lungs
if large quantities of tiotropium are swallowed instead of inhaled we might expect to see anticholinergic effects in the ____ as we’ll
GI system
along with bronchodilation, anticholinergics also do what to contribute to clearing airways?
decreased mucus secretions
tropic amid eyedrops are an example of a ___ drug
anticholinergic
why re tropic amide eyedrops used in eye exams?
they dilate pupil, allowing more light to enter for improved examination of the retina and its vasculature
t/f because scopolamine is used systemically, it can have unintended effects, but when used for short durations, these effects can be tolerable
true
what is scopolamine?
tertiary amine muscarinic receptor antagonist
what form is scopolamine available as?
transdermal patch
scopolamine is absorbed ____ (locally or systemically)
systemically
the anticholinergic activity of diphenhydramine and dimenhydramine can effectively reduce ___ but also causes anticholinergic and antihistamine effects in other systems: ___, ____, ___ and ___ may occur in some patients
nausea; sedation, dry mouth, ataxia and confusion
t/f because scopolamine is used systemically, it can have unintended effects, but when used for short durations, these effects can be tolerable
true
one example of a commonly used drug having off-target anticholinergic effects are the first generation antihistamines such as ___
diphenhydramine
gravol; or the generic name dimenhydrinate is a combination of ____ and ___
diphenhydramine and a stimulant – chlorotheophylline
first generation antihistamines are notorious for having ___ effects, thus the addition of stimulant makes it less sedative than diphenhydramine itself
sedative
the anticholinergic activity of diphenhydramine and dimenhydramine can effectively reduce ___ but also causes anticholinergic and antihistamine effects in other systems: ___, ____, ___ and ___ may occur in some patients
nausea; sedation, dry mouth, ataxia and confusion
drugs that act on multiple receptors are often called ___- drugs
dirty
