Muscarinic Antagonists

Question 1

Antimuscarinic

Answer 1

acts at the post-ganglionic neuroeffector junction to block parasympathetic autonomic discharge

Question 2

Neuromuscular blocker

Answer 2

acts at the neuromuscular junction to block acetylcholine signaling

Question 3

Ganglionic blockers

Answer 3

act as antagonists at both parasympathetic and sympathetic autonomic ganglia

Question 4

M1, M3 and M5 receptors signal via

Answer 4

intracellular Ca2+ increase and PKC activity

Question 5

M2 and M4 receptors signal via

Answer 5

cAMP decrease and reduced cAMP-dependent PK activity

Question 6

M1 (G alpha q) receptors are located where?

Answer 6

CNS, sympathetic postganglionic cells and presynaptic sites

Question 7

M3 (G alpha q) receptors are located where?

Answer 7

smooth muscle, lungs, eyes, effector cell membranes

Question 8

M2 (G alpha I) receptors are located where?

Answer 8

myocardium, smooth muscle, and presynaptic sites (K+ channel linked = slow heart rate)

Question 9

M4 (G alpha I) receptors are located where?

Answer 9

in the CNS

Question 10

Atropa belladonna

Answer 10

deadly nightshade

Question 11

Primary clinical uses for antimuscarinic drugs

Answer 11

ocular exams, incontinence, irritable bowel syndrome

Question 12

Secondary clinical uses for antimuscarinic drugs

Answer 12

COPD, pre-operative anti-secretory, motion sickness, Parkinson’s disease

Question 13

Antimuscarinic drug use in ocular exams

Answer 13

mydyriasis (pupil dilation): inhibits Ach action on M3 receptors in pupillar constrictor muscles
cycloplegia (loss of focus/lens thickness): inhibits Ach action of M3 receptors in the ciliary muscles

Question 14

Antimuscarinic drug use for incontinence

Answer 14

bladder relaxation: inhibits M3 receptors (mediate contraction of the bladder) and M2 receptors (which inhibit relaxation)

Question 15

Antimuscarinic drug use for irritable bowel syndrome

Answer 15

induces GI tract intestinal paralysis and reduces secretions

Question 16

Mebeverine

Answer 16

antimuscarinic drug used for IBS

Question 17

Antimuscarinic drug use in COPD

Answer 17

reduces secretions, causes bronchial dilation in combination with a beta-adrenergic agonist

Question 18

Antimuscarinic drug use pre-operative (anti-secretory)

Answer 18

used with inhalant anesthetics to reduce accumulations of secretions (salivary, mucous membranes of respiratory tract)

Question 19

Long lasting tertiary amines

Answer 19

atropine and scopolamine

Question 20

Atropine and Scopolamine are used to treat

Answer 20

GI/urinary conditions, COPD, motion sickness, adjuct for Parkinson’s

Question 21

Side effets of Scopolamine

Answer 21

drowsiness (low dose) or hallucinations (high doses)
confusion, dilated pupils, tachycardia
can cause amnesia

Question 22

What happens when scopolamine treatment is stopped suddenly

Answer 22

rebound effects - causing an overstimulation of the vesitubular nuclei and the reticular formation of the vomiting center (nausea, headache, and blurred vision)

Question 23

Scopolamine can be specifically used for

Answer 23

motion sickness and reducing nausea (scopolamine patch)

Question 24

How can the withdrawal symptoms of scopolamine be alleviated

Answer 24

using anti-histamines or leaving the scopolamine patch on for a longer time to “squeeze out” the last bit of scopolamine over a prolonged time

Question 25

Tropicamide is primarily used for

Answer 25

eye exams

Question 26

What does tropicamide cause

Answer 26

cycloplegia and mydriasis

Question 27

Why would you want to dilate the pupil when evaluating a patient with glaucoma?

Answer 27

a dilated pupil enables examination of the terminal ends of the optical nerve and the nerves at the terminus are thinner and the first to be damaged by glaucoma

Question 28

Types of urinary incontinence

Answer 28

Stress incontinence, urge incontinence, outflow incontinence, functional incontinence

Question 29

Stress incontinence

Answer 29

laxity of pelvic floor muscle, leaks with cough or laughing, history of vaginal childbirth

Question 30

Treat stress incontinence with

Answer 30

adrenergic agonists

Question 31

Urge incontinence

Answer 31

increased detrusor muscle activity (overactive bladder), nocturia, small volume, increased frequency

Question 32

Treat urge incontinence with

Answer 32

anti-cholinergics

Question 33

Outflow incontinence

Answer 33

urinary retention secondary to obstruction or bladder atony, nocturia, small volume, increased frequency

Question 34

Treat outflow incontinence with

Answer 34

cholinergics (atony) or alpha antagonists (obstruction)

Question 35

Functional incontinence

Answer 35

due to large volume intake

Question 36

How can gestational diabetes cause incontinence

Answer 36

gestational diabetes -> increased baby weight -> damage to bladder sphincter

Question 37

How can congestive heart failure cause incontinence

Answer 37

CHF -> retain water -> create too much urine at night -> nocturia

Question 38

How are muscarinic antagonists used to treat urinary incontinence

Answer 38

by relaxing the obtrusor muscle in the bladder and increasing maximal bladder volume

Question 39

What kind of muscarinic receptors does the bladder contain?

Answer 39

both M2 and M3 receptors

Question 40

Prolonged use of muscarinic antagonists for urinary incontinency may lead to

Answer 40

acute urinary retention

Question 41

M3 selective muscarinic antagonists used for urinary incontinence

Answer 41

Darifenacin and Solifenacin

Question 42

M2/M3 selective muscarinic antagonist used for urinary incontinence

Answer 42

Tolterodine

Question 43

M1/M3 selective muscarinic antagonist used for urinary incontinence

Answer 43

Oxybutynin (dry mouth is a common side effect)

Question 44

Probanthine

Answer 44

used to treat gastric disorders (GI spasms, peptic ulcers), peripherally restricted

Question 45

Antispasmotics are used for?

Answer 45

irritable bowel syndrome

Question 46

Name 3 antispasmotics

Answer 46

Atropine, Dicyclomine, Hyoscyamine

Question 47

When should you avoid using antispasmotics?

Answer 47

avoid in glaucoma patients and avoid long term/continuous use

Question 48

How do M3 antagonists work in COPD?

Answer 48

M3 receptors mediate constriction of bronchial smooth muscle so M3 antagonists will block Ach-mediated constriction and open the airways

Question 49

muscarinic antagonists used for COPD

Answer 49

"-tropium" | Ipratropium, Tiotropium

Question 50

Ipratropium

Answer 50

short acting, rescue inhaler for COPD

Question 51

Tiotropium

Answer 51

long acting, daily inhaler for COPD

Question 52

Muscarinic antagonists for the management of COPD and asthma are more effect when?

Answer 52

when co-administered with a beta2 blocker

Question 53

Drug classes known to contain drugs with anti-cholinergic activity

Answer 53

anti-histamines, anti-psychotics, TCA's and anti-arrythmics

Question 54

Tricyclic anti-depressant choice for the elderly

Answer 54

Nortryptaline because it only has mild-moderate anti-cholinergic effects

Question 55

Common contraindications for anti-muscarinic drugs

Answer 55

open/narrow angle glaucoma, tachycardia, ileus (intestinal obstruction), urinary obstruction (BPH)