04- Cholinergics Flashcards Preview

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Flashcards in 04- Cholinergics Deck (49)
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1

atropine

cholinergic antagonist that is MUSCARINIC selective
-no selectivity for Muscarinic sub-types
-tertiary amine so easily cross BBB and cause CNS toxicity
-quickly distributed after administration (30-60 min in CNS)
-duration of action 5-10 hours
-most sensitive tissues are salivary, bronchial, and sweat glands
-has LONG-acting topical application used in eyes that elicits mydriasis and cycloplegia, relieves urinary incontinence, may be useful adjunct therapy for Parkinsonism, overcome poisoning by O-P or muscarine mushrooms, and can inhibit some vagal slowing of heart due to MI

2

homatropine

cholinergic antagonist that is MUSCARINIC selective
-tertiary amine so can cross BBB (mainly used topically so this does not normally occur)
-duration of action 2-4 hours
-has INTERMEDIATE-acting topical application that is useful for eliciting mydriasis and cycloplegia (for eye exams)

3

scopolamine

cholinergic antagonist that is MUSCARINIC selective
-quickly distributed after admin (30-60 min in CNS)
-duration of action 5-10 hours
-tertiary amine derivative primarily used for CNS effects (CNS depression manifested with drowsiness, amnesia, fatigue, dreamless sleep)
-most effective treatment for motion sickness
-side effects include sedation and dry mouth

4

methscopolamine (Pamine)

cholinergic antagonist that is MUSCARINIC selective
-duration of action 5-10 hours
-quaternary derivative of scopolamine so only used in PNS and lacks CNS effects
-primarily used for GI diseases

5

trihexyphenidyl (Artane)

cholinergic antagonist that is MUSCARINIC selective
-tertiary amine that readily crosses BBB and can cause CNS toxicity
-duration of action 3-6 hours
-useful adjunct therapy to dec. uncoordinated movement and excess salivation for Parkinsonism (main use) and extra-pyramidal side effects of anti-psychotics

6

cyclopentolate (Cyclogyl)

cholinergic antagonist that is MUSCARINIC selective
-short acting (3-6hrs) topical application to induce mydriasis and cycloplegia
-non-specific muscarinic blocker so can exhibit all associated effects of muscarinic blockade

7

ipratroprium (Atrovent)

cholinergic antagonist that is MUSCARINIC selective
-aerosol, synthetic analog of atropine
-quaternary derivative of atropine
-bronchodilation, tachycardia, decreased salivation
-minimizes mucociliary clearance effect and is useful for patients with airway problems (maintains airway fluidity)
-specifically targeted when used as an inhalant and unable to cross membranes (so will only bronchodilate)
-used for patients with COPD

8

tiotropium (Spiriva)

cholinergic antagonist that is MUSCARINIC selective
-synthetic analog of atropine
-serves as LONGER ACTING "topical" inhalation application that targets bronchodilation and specifically minimizes mucociliary clearance problems (maintains airway fluidity)

9

darifenacin (Enablex)

cholinergic antagonist that is M3 selective
-slows micturition
-aids in treatment of urinary urgency due to inflammatory bladder problems
-may alleviate bladder spasm following urologic surgery
-may precipitate urinary retention in men with prostatic hyperplasia

10

solifenacin (VESIcare)

cholinergic antagonist that is M3 selective
-slows micturition
-aids in treatment of urinary urgency due to inflammatory bladder problems
-may alleviate bladder spasm following urologic surgery
-may precipitate urinary retention in men with prostatic hyperplasia

11

tolterodine (Detrol)

cholinergic antagonist that is M3 selective
-slows micturition
-aids in treatment of urinary urgency due to inflammatory bladder problems
-may alleviate bladder spasm following urologic surgery
-may precipitate urinary retention in men with prostatic hyperplasia

12

mecamylamine (Inversine)

cholinergic antagonist that is NICOTINIC selective
-acts as non-depolarizing competitive antagonist
-secondary amine developed to improve absorption from GI tract following oral administration
-Duration of action: 12 hours
-CNS side effects include tremors, confusion, seizures, mania, depression

13

trimethaphan (Arfonad)

cholinergic antagonist that is NICOTINIC selective
-acts as non-depolarizing competitive antagonist
-sulfonium (positively charged sulfur group) developed for IV use (lasts minutes)
-used during surgery to minimize blood loss in OR
-monitor carefully for excessive hypotension and brain anoxia

14

succinylcholine

-cholinergic antagonist that is DEPOLARIZING
-non-competitive receptor agonist that opens Na+ channels and mimics effect of ACh
-not substrate for AChE, but activity short because broken down by plasma cholinesterase
-only depolarizing NM blocker
-Phase I block (depolarizing): membrane remains depolarized and unresponsive inducing flaccid paralysis
-Phase II block (desensitizing): membrane repolarizes but receptor is desensitized due to prolonged exposure to Succ.
-cannot reverse action of succinylcholine***

15

curare (d-tubocurarine)

cholinergic antagonist that is NON-DEPOLARIZING
-LONG-acting benzylisoquinoline that competes with ACh for binding to N2 receptor sites which prevents depolarization of membrane and flaccid paralysis
-devoid of vagolytic and ganglionic blocking activity
-may elicit some histamine release
-poor lipid solubility so cannot cross BBB
-can be reversed by AChE inhibitor which leads to more ACh at synapse which can compete off antagonist from receptor

16

atracurium (Tracrium)

cholinergic antagonist that is NON-DEPOLARIZING
-competes with ACh for binding to N2 receptor sites which prevents depolarization of membrane and flaccid paralysis
-poor lipid solubility so cannot cross BBB
-can be reversed by AChE inhibitor which leads to more ACh at synapse which can compete off antagonist from receptor

17

cisatracurium (Nimbex)

cholinergic antagonist that is NON-DEPOLARIZING
-INTERMEDIATE-acting benzylisoquinoline that competes with ACh for binding to N2 receptor sites which prevents depolarization of membrane and flaccid paralysis
-devoid of vagolytic and ganglionic blocking activity
-may elicit some histamine release
-poor lipid solubility so cannot cross BBB
-can be reversed by AChE inhibitor which leads to more ACh at synapse which can compete off antagonist from receptor

18

mivacurium (Mivacron)

cholinergic antagonist that is NON-DEPOLARIZING
-SHORT-acting benzylisoquinoline that competes with ACh for binding to N2 receptor sites which prevents depolarization of membrane and flaccid paralysis
-devoid of vagolytic and ganglionic blocking activity
-may elicit some histamine release
-poor lipid solubility so cannot cross BBB
-can be reversed by AChE inhibitor which leads to more ACh at synapse which can compete off antagonist from receptor

19

pancuronium (Pavulon)

cholinergic antagonist that is NON-DEPOLARIZING
-LONG-acting ammonio steroid that causes neuromuscular blockade by competing with ACh for binding to N2 receptor sites which prevents depolarization of membrane and flaccid paralysis
-will have some muscarinic block leading to vagal blockade and tachycardia
-poor lipid solubility so cannot cross BBB
-can be reversed by AChE inhibitor which leads to more ACh which can compete off antagonist from receptor

20

vecuronium (Norcuron)

cholinergic antagonist that is NON-DEPOLARIZING
-INTERMEDIATE-acting ammonio steroid that causes neuromuscular blockade by competing with ACh for binding to N2 receptor sites which prevents depolarization of membrane and flaccid paralysis
-will have some muscarinic block leading to vagal blockade and tachycardia
-poor lipid solubility so cannot cross BBB
-can be reversed by AChE inhibitor which leads to more ACh which can compete off antagonist from receptor

21

Cholinergic Antagonists

block the effects of ACh and ACh-like agonists from interacting with the various nicotinic and muscarinic receptors and prevent the normal physiological responses caused by these receptors

22

Anti-Muscarinic (parasympatholytics) Agents

anticholinergic drugs that combine with muscarinic receptors (M1-M3) and prevent physiologic responses to ACh at post-ganglionic parasympathetic transmission sites
-used when both mydriasis and cycloplegia are required
-block vagal slowing of the heart due to antagonism of muscarinic receptors on SA and AV nodes
-elicit bronchodilation and decreased secretions in airway
-decrease smooth muscle motility and secretions in GI tract
-decrease activity of salivary glands and thermoregulatory sweat glands
-relax smooth muscle of genitourinary system
-have anti-parkinson, anti-motion sickness and amnesic properties

23

Anti-Nicotinic Agents

anticholinergic agents that block nicotinic receptors
-ganglionic blockers (N1)
-NMJ blockers (N2)

24

Tertiary Amine

nitrogen forming 3 bonds and has a neutral charge
-derivatives can cross mucous membranes and BBB to exert effects on CNS

25

Quaternary Ammonium

-positively charged nitrogen that forms 4 bonds
derivatives do not cross membrane boundaries due to poor lipid solubility from charged N group
-avoid CNS effects because does not cross BBB
-poor and unreliable oral absorption
-poor absorption across conjuctiva

26

Why can't we reverse a neuromuscular block created by succinylcholine (Succ) with neostigmine (Neo)?

neostigmine is an AchE inhibitor leading to increased Ach in the neuromuscular junction. Succ is a depolarizing neuromuscular blocker which acts as a Nm receptor agonist. Increasing the amount of Ach in the neuromuscular junction will augment and increase the depolarization further.

27

edrophonium

-Competitive inhibitor of cholinesterase (reversible, short-acting)
-simple alcohol with Quaternary ammonium (binds to active site on AChE)
-Major uses: myasthenia gravis, ileus, arrhthmias
-Duration of action: 5-15 minutes

28

carbaryl (Sevin)

Organophosphate insecticide. AChE inhibitor

29

malathion

Organophosphate insecticide. AChE inhibitor

30

parathion

Organophosphate insecticide. AChE inhibitor