Anticholinergic Agents/Muscarinic Antagonists

Question 1

What is the MOA of anticholinergics/muscarinic antagonists?

Answer 1

competitive inhibitors of ACh at parasympathetic muscarinic receptors to increase HR

Question 2

What effects do anticholinergics/muscarinic antagonists have on the body?

Answer 2

• increased HR
• salivary inhibition
• decreased bronchial and GI secretions
• decreased gastric motility
• bronchodilation

Question 3

What are muscarinic antagonists/anticholinergics used for?

Answer 3

to antagonize the muscarinic effects of anticholinesterases used to reverse NMBA

Question 4

Atropine Dosing

Answer 4

• 0.014 mg per 1mg of edrophonium
• 0.2 - 0.4 mg for vagal stimulation

Question 5

Atropine onset and duration

Answer 5

Onset: < 1 min
Duration: up to 30 min

Question 6

Is atropine a quaternary or tertiary amine? Can it cross the BBB?

Answer 6

• tertiary amine
• it CAN cross the BBB

Question 7

When is atropine used?

Answer 7

• reversal with edrophonium
• brady arrythmias
• vagal stimulation
• oculocardia reflex
• peritoneal stimulation

Question 8

What is the effect of atropine in the fetus?

Answer 8

crosses the placenta and increases FHR, decreasing beat to beat variability

Question 9

We should very carefully use atropine in patients with ___________

Answer 9

narrow-angle glaucoma

Question 10

Glycopyrrolate Dosing

Answer 10

0.2 mg per 1mg of neostigmine

Question 11

Glycopyrrolate onset and duration

Answer 11

Onset: 1 min IV; 15-30 min IM
Duration: 2-4 hours

Question 12

What is the MOA of glycopyrrolate?

Answer 12

• synthetic antimuscarinic
• competitive ACh antagonist

Question 13

When is glycopyrrolate used?

Answer 13

• reversal with neostigmine
• antisialogogue (xerostomia)
• to increase HR (not as intense as atropine)

Question 14

Is glycopyrrolate a quaternary or tertiary ammonium? Can it cross the BBB?

Answer 14

• quaternary ammonium
• CANNOT cross the BBB

Question 15

What two side effects are not seen in glycopyrrolate that would normally be seen in other muscarinic antagonists?

Answer 15

• no CNS effects
• no mydriasis

Question 16

Scopalamine Dosing

Answer 16

0.3 - 0.5 mg IV or IM

Question 17

What is the MOA of scopalamine?

Answer 17

• competitive antagonist of ACh at muscarinic receptors
• antagonizes histamine and serotonin

Question 18

Is scopalamine a quaternary or tertiary amine? Can it cross the BBB?

Answer 18

• tertiary amine (naturally occurring alkaloid)
• it CAN cross the BBB

Question 19

When is scopalamine used?

Answer 19

• to decrease secretions
• decrease PONV
• motion sickness/vertigo
• dilate pupils/cycloplegia
• unstable trauma patient
• sedation/amnesia

Question 20

What is the effect of scopalamine in elderly?

Answer 20

can cause toxic psychosis

Question 21

T/F: It is safe to use scopalamine in elderly

Answer 21

false
- can cause toxic psychosis

Question 22

What is an important thing to do after you administer or place a scopalamine patch?

Answer 22

wash your hands!!!!
can easily cause your eyes to dilate

Question 23

What are common CNS effects of scopalamine?

Answer 23

• restlessness
• agitation

Question 24

What routes of administration are available for scopalamine?

Answer 24

• IM
• IV
• transdermal patch

Question 25

If a patient is prescribed a trasdermal patch for scopalamine, what should we warn them about?

Answer 25

• very blurry vision
• vertigo
• dizziness
• risk of falling

Question 26

Can we overdose on muscarinic antagonists?

Answer 26

yes - leads to anticholinergic syndrome

Question 27

What can be a cause of anticholinergic syndrome?

Answer 27

overdose of atropine, scopalamine, or phenothiazine

Question 28

What are s/s of anticholinergic syndrome?

Answer 28

• anxiety
• disorientation
• hyperactive (mad hatter)
• sedation
• seizure
• mydriasis (blind as a bat)
• increased HR
• atropine flush (red as a beet)
• dry/flushed skin and mucous membranes (dry as a bone)
• atropine fever (hot as a hare)