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Pharmacology > Cholinergic Antagonists > Flashcards

Cholinergic Antagonists Flashcards

1
Q

Cholinergic Antagonists (anticholinergic)–> Muscarinic

A

MUSCARINIC–> antimuscarinic, blocks effects of parasympathetic autonomic discharge

ex: atropine and scopolamine

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2
Q

Cholinergic Antagonists–> Nicotinic

A

ganglionic blockers (autonomic NS)
NMJ
ex: tetraethylammonium, tubocurarine, succinylcholine

drugs block outflow past autonomic level, so you wont get any adrenergic or muscarinic action

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3
Q

Atropine

A

comes from plants, like atropa belladonna

meds with similar structure to atropine such as antihistamines, phenothiazine and tricyclic-antidepressants will have anticholinergic side fx

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4
Q

Actions of Atropine

A

Reversibly blocks muscarinic receptors (prevents ACh from binding to it.

used as an antidote if someone is exposed to a pharmacological agent that is a muscarinic agonist

tissues most sensitive to atropine are salivary, bronchial and sweat glands

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5
Q

Tissues affected by Atropine

A

Eye, CV system, respiratory system, GI tract, GU tract, sweat glands, CNS

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6
Q

CNS Effects of Anticholinergics

A

Atropine has minimal effect or use (doesnt cross BBB)

Scopolamine crosses BBB-causes drowsiness, amnesia, too much can cause toxicity

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7
Q

Antimuscarinics to tx Parkinsons

A

may be used as adjuncts to tx remor seen in parkinsons–benzotropine

in parkinsons there is an imbalance between dopamine and ACh (too much ACh) so you give something that will block the action of the ACh

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8
Q

Antimuscarinics to tx Motion Sickness

A

Scopolamine–>used to tx or prevent motion sickness. Injection, oral, or transdermal patch (lipophilicty so can be absorbed through the skin)

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9
Q

Effects of Antimuscarinics on the Eye

A

block cholinergic stimulation of pupillary constrictor muscle=pupillary dilation (mydriasis)

Prevent contraction of ciliary muscle, resulting in cycloplegia–> loss of accomidation (prevents focusing on near objects)

reduces lacrimal secretion=dry eyes

can dangerously worsen narrow angle glaucome due to lack of outflow of aqueous humor (causes high IOP)

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10
Q

Effects of Antimuscarinics on Cardiovascular System–low Dose (.5mg)

A

blocks M1 receptors only

will see bradycardia, ACh will still be bindign to M3 receptors on sinus node

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11
Q

Effects of Antimuscarinics on Cardiovascular System–Medium Dose (1-5mg)

A

Blocks M2 receptors in SA and AV node

(M2 usually slows heart rate) so blocking M2=tachycardia because of vagal slowing

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12
Q

Effects of Antimuscarinics on Cardiovascular System–Toxic Dose (greater than 10mg)

A

can cause intraventricular conduction block–inhibits electrical pulse generation in pacemaker nodes

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13
Q

Therapeutic uses of Antimuscarinics in CV Disorders

A

In acute MI–>can be used in pt’s that have bradycardia after MI, can give median dose to increase HR and C/O

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14
Q

Effects of Anticholinergics on Respiratory System

A

bronchodilation and reduce/dry up secretions

ex: Ipratropium (atrovent, spiriva)

atropine and scopolamine useful to dry upper and lower respiratory secretions prior to surgery or mechanically vented pt’s

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15
Q

Affects of Antimuscarinics on GI Tract

A

reduces GI smooth muscle motility, prolongs gastric emptying time and slowing intestinal transit time, reduces GI secretions

Antimuscarinic agents reduce salivary agents –>dry mouth (xerostomia)

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16
Q

Therapeutic uses of Antimuscurinics in GI Disorders

A

tx diarrhea (reducing GI secretions), combined with lomotil to slow down gut motility

17
Q

Effects of Antimuscarinics on GU

A

Cause relaxation of smooth muscles in ureter and bladder (detruser muscle)–reduces voiding (runiary retention)

contraindicated in people who have BPH

18
Q

Theraputic uses of Antimuscarinics in Urinary Disorders

A

rx urinary tract spasm associated with inflammation, surgery or neurologic conditions

Oxybutinin (Ditropan)-> used to tx urinary incontinence–> targets M3 receptor

trospium
darifenacin
solifenacin
tolterodine

19
Q

Therapy for Muscarinic Toxicity

A

Atropine
atropine effective for central and peripheral symptoms from potent cholinomimetics (organophosphates)

pralidoxime-recycles aAChE–> allows for more breakdown of ACh to help reduce cholinergic activity

20
Q

Effects of Anticholinergics on Sweat Glands

A

tx hyperhidrosis, especially effective on eccrine glands

Ex: glycopyrrolate (Robinul)

21
Q

Anticholinergic Adverse Effects

A

dry mouth, mydriasis, tachycardia, hot, flushed skin, agitation, urinary retention, visual changes, constipation

22
Q

Contraindicated use of Anticholinergics

A

glaucoma (anticholinergics will cause angle closure preventing outflow of aqueous humor

men with BPH

pt’s with gastric ulcers (because of slwoed gastric emptying will make it worse)

23
Q

Presynaptic Inhibition of Cholinergic Action

A

clostridium botulinum

targets presynaptic proteins that block the release of ACh–>blocks release of ACh=paralysis of muscles=no more wrinkles

24
Q

Ganglionic Blocking Agents

A

Tetraethylammonium (TEA)
Hexamethonium (C6)
Mecamylamine
Trimethaphan

block all autonomic outflow by by blocking ACh at nicotinic receptors of parasympothetic and sympathetic ganglia

25
Q

Effects of Ganglionic blockers on CNS

A

sedation, tremor, choreiform movements, mental aberrations

26
Q

Effects of Ganglionic blockers on Eye

A

cycloplegia, loss of accommodation, moderate dilation of pupil

27
Q

Effects of Ganglionic Blockers on CV system

A

tachycardia

28
Q

Effects of Ganglionic Blockers in GI tract

A

decreased secretions, decreased motility

29
Q

Neuromuscular Blockers

A

block neuromuscular transmission between motor end plate and nicotinic receptors in skeletal muscle

30
Q

Two Groups of Meruomuscular Blockers

A

Nondepolarizing (antagonists)

Depolarizing (agonists)

31
Q

Nondepolarizing Neuromuscular Blockers

A

block ACh from binding to nicotinic receptors=prevents depolarization, inhibits contraction=relaxed paralyzed muscle

bind in competitive fashion (nondepolarizing blockers bind to nicotinic receptors)

can be overcome with AChE Inhibitors

32
Q

Use of Nondepolarizing Neuromuscular Blockers

A

used in surgery to produce muscular paralysis

Ex: tubocurarine, mivacurium, atracurium, doxacurium, pancuronium, cistracurium, vecuroium, rocuronium

33
Q

Depolarizing Neuromuscular Blockers

A

Succinylcholine–super agonist

bind to nicotinic receptors on skeletal muscle acts like ACh–> provides constant stimulation of receptor= resistant to further depolariztion and paralysis results (muscles are overstimulated and dont get a chance to depolarize again)

34
Q

Therapeutic Uses of Depolarizing Neruomuscular Blockers

A

facilitate intubation, during electroshock therapy

Pharmacology (21 decks)

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