Muscarinic antagonists

Question 1

muscarinic antagonists generally

Answer 1

block the effects of ACh at M1, M2, M3, antagonizing parasympathetic stimulation

Question 2

atropine and scopolamine are found in

atropine is also found in

Answer 2

belladonna plant

jimson weed

Question 3

atropine CNS effects

Answer 3

NONE except at toxic doses.

therefore mostly has peripheral effects

Question 4

scopolamine CNS effects

Answer 4

enters CNS easily –> sedation, amnesia, euphoria (can be abused)

Question 5

scopolamine is well absorbed ________, and is used for _________

Answer 5

through the skin

transdermal patch for motion sickness

Question 6

at low doses of atropine, the main effects are

Answer 6

dry mouth, decreased sweating

Question 7

as atropine dose is increased effects include

Answer 7

tachycardia, blurred vision, palpitations

Question 8

at moderately high (but not high enough to penetrate CNS) doses, atropine causes

Answer 8

urinary retention, hot and dry skin, restlessness, fatigue

Question 9

when toxic doses of atropine penetrate the CNS, it causes

Answer 9

ataxia, hallucinations, delirium, coma, rapid and weak pulse

Question 10

common drugs that block muscarinic receptors and might be seen in poisoning

Answer 10

antihistamines, antidepressants, and antipsychotics

Question 11

low doses of scopolamine CNS effects

Answer 11

drowsiness, amnesia

Question 12

toxic doses scopolamine effects

Answer 12

excitement, agitation, hallucinations, coma

Question 13

why would scopolamine be used for pre-anesthesia

Answer 13

sedation, amnesia, decrease sedations

Question 14

situations where DA receptors are blocked or DA is reduced causing imbalance of ACh/DA in the corpus striatium

Answer 14

Antipsychotic drugs

Parkinsons

Question 15

3 antimuscarinics used to restore the ACh/DA balance in the corpus striatum

Answer 15

trihexyphenidyl, benztropine, diphenhydramine

Question 16

in the elderly, antimuscarinic drugs cause

Answer 16

memory impairment, delirium, dementia

Question 17

risks of long term antimuscarinic use

Answer 17

Alzheimer’s

Question 18

antimuscarinic effects on the eye

Answer 18

block circular muscle --> mydriasis
block ciliary muscle --> cycloplegia
block reflex to light --> photophobia
block lacrimation --> dry eyestac
(used for eye exams)

Question 19

loss of accommodation is called

Answer 19

cycloplegia

Question 20

contraindications to the use of antimuscarinics, and why

Answer 20

narrow angle glaucoma

blockage of ciliary muscle –> closed trabecular system –> increased intraocular pressure

Question 21

antimuscarinics cause tachycardia because

Answer 21

Presynaptic M2 autoreceptors are blocked –> increased NE

Postsynaptic M2 autoreceptors are blocked –> vagal effects (reflex bradycardia) removed

Question 22

tachycardia due to antimuscarinics is most noticeable in ________ and least noticeable in ________ due to __________

Answer 22

healthy young adults
elderly, babies
they have little vagal tone

Question 23

drug used to prevent vagal bradycardia when visceral organs are being handled during surgery

Answer 23

glycopyrrolate

Question 24

drug used in MI to decrease bradycardia or MI block

Answer 24

atropine

Question 25

reflex vagal discharge

Answer 25

due to pain, stimulation of carotid sinus, pressure on the eyeballs, irritation of the larynx during intubation ----> and AV node depression ---> bradycardia, decreased CO

Question 26

used to reverse reflex vagal discharge

Answer 26

atropine

Question 27

used to reverse bradycardia produced by muscarinic agonists/cholinesterase inhibitors

Answer 27

atropine

Question 28

used to block decrease in blood pressure seen with IV muscarinic agonists at M3 receptors

Answer 28

atropine

Question 29

M3 receptors on endothelial cells cause vasodilation by

Answer 29

releasing nitric oxide in response to a muscarinic agonist

Question 30

toxic doses of atropine cause _______ because _______

Answer 30

vasodilation in the face | happens to offload excess heat since sweating is blocked

Question 31

antimuscarinics, pre-anesthia respiratory effects

Answer 31

inhibit secretions of salivary gland/respiratory tract | decrease laryngospasm

Question 32

compounds use in the lung are

Answer 32

quaternary ammonium compounds, inhaled w/o systemic absorption.

Question 33

ipratropium and tirtropium are

Answer 33

bronchodilators for asthma, COPD

Question 34

antispasmodics

Answer 34

drugs that decrease motility and secretions in GI tract

Question 35

commonly used antispasmodic

Answer 35

dicyclomine

Question 36

treatment of diarrhea that has low potential for abuse because of side effects with higher doses

Answer 36

atropine (blocks GI) + diphenoxylate (opioid, synergistically blocks GI)

Question 37

name for atropine + diphenoxylate

Answer 37

lomotil

Question 38

diphenoxylate is an

Answer 38

opioid

Question 39

drug to decrease bladder overactivity

Answer 39

tolterodine

Question 40

tolterodine is the preferred drug for bladder control in the elderly in whom muscarinic blockade can cause delirium because

Answer 40

M3 specific --> few side effects | No CNS effects

Question 41

drugs that are similar to tolterodine

Answer 41

fesoterodine, darifenacin, solifenacin

Question 42

drug used to prevent bladder spasm after prostate surgery

Answer 42

oxybutnin

Question 43

drug used to prevent bladder spasm after prostate surgery that causes less dry mouth

Answer 43

tropspium

Question 44

use for glycopyrrolate (outside the OR)

Answer 44

decrease muscarinic effects of AChE inhibitors in MG patients

Question 45

contraindication of antimuscarinics in old men

Answer 45

BPH due to increased urinary retention

Question 46

what's that weird saying for atropine poisoning

Answer 46

dry as a bone, blind as a bat, mad as a hatter, red as a beet

Question 47

who's sensitive af to atropine poisoning and why

Answer 47

infants/children due to sensitivity to hyperthermia

Question 48

symptoms of atropine poisoning

Answer 48

dry mouth, mydriasis, tachycardia, decreased bowel sounds, hot flushed skin, agitation, delirum

Question 49

scopolamine poisoning, for added fun, causes

Answer 49

atropine poisoning effects + toxic psychosis (it enter CNS)

Question 50

treatment for atropine poisoning and reasoning

Answer 50

systemic physostigmine, it gets into the CNS

Question 51

treat direct acting muscarinic agonist poisoning with

Answer 51

atropine (also organophosphate poisoning)