Autonomic Parasymathetic Drugs: Muscarinic Antagonists

Question 1

muscarinic antagonists reversibly block

Answer 1

muscarinic receptors

Question 2

antimuscarinics block the muscarinic effects of

Answer 2

antimuscarinics block the muscarinic effects of diarrhea, urination, miosis, bronchospasm, bradycardia, lacrimation, salivation

Question 3

antimuscarinics block the action of

Answer 3

antimuscarinics block the action of acetylcholine at M receptors

Question 4

Atropine is an

Answer 4

antimuscarinic

Question 5

Atropine and related antimuscarinic alkaloids are found in

Answer 5

1. the flower Atropa belladonna (‘Deadly Nightshade’)

2. the plant Datura stramonium (‘Jimsonweed’)

Question 6

antimuscarinics cause

Answer 6

pupillary dilation (mydriasis) and cycloplegia (inability to accommodate the lens for near vision)

Question 7

Antimuscarinics include

Answer 7

1. scopolamine

2. atropine

Question 8

scopolamine is used to treat

Answer 8

motion sickness (vestibular nausea)

Question 9

scopolamine transdermal patch is used to treat

Answer 9

motion sickness

Question 10

antimuscarinics (e.g. scopolamine) cross

Answer 10

antimuscarinics (e.g. scopolamine) cross the blood-brain barrier and inhibits central M1 receptors

Question 11

antimuscarinics block parasympathetic activation of M2

Answer 11

antimuscarinics block parasympathetic activation of M2 receptors on the SA and AV nodes (increased heart rate, increased AV conduction)

Question 12

antimuscarinics block parasympathetic activation of __________ receptors on the SA and AV nodes (increased heart rate, increased AV conduction)

Answer 12

M2

Question 13

antimuscarinics (e.g. atropine) increase

Answer 13

1. heart rate

2. AV conduction

Question 14

antimuscarinics are used to treat

Answer 14

1. Bradycardia

2. Heart Block

Question 15

ipratropium and tiotropium are useful in the management of

Answer 15

COPD (antagonize M3 receptors → bronchodilation, decreased secretions)

Question 16

ipratropium and tiotropium are ________ antimuscarinic bronchodilators

Answer 16

inhaled antimuscarinic bronchodilators

Question 17

_______ dissociates more slowly from the M3 receptor (longer bronchodilator action)

Answer 17

tiotropium

Question 18

M3 muscarinic antagonist

Answer 18

1. oxybutynin
2. ipratropium
3. tiotropium
4. Tolterodine

Question 19

oxybutynin and tolterodine treat

Answer 19

oxybutynin and tolterodine treat incontinence (antagonize M3 receptors → relax smooth muscle in ureters and bladder wall)

Question 20

M1 muscarinic receptors are found in the

Answer 20

CNS

Question 21

M1 receptor antagonists can reduce

Answer 21

M1 receptor antagonists can reduce tremors and rigidity in Parkinson’s disease

Question 22

centrally acting M1 muscarinic antagonist

Answer 22

1. benztropine

2. trihexyphenidyl

Question 23

centrally acting antimuscarinics (e.g. benztropine, trihexyphenidyl) treat

Answer 23

centrally acting antimuscarinics (e.g. benztropine, trihexyphenidyl) treat tremor and rigidity in Parkinson’s (block excess cholinergic activity)

Question 24

excessive M1 activation is associated with

Answer 24

cogwheel rigidity in Parkinson’s disease

Question 25

antimuscarinics treat

Answer 25

extrapyramidal side effects caused by antipsychotics: e.g. dystonia, akathisia, parkinsonism (re-establish dopaminergic- cholinergic balance)

Question 26

antimuscarinics inhibit M3 receptors on

Answer 26

antimuscarinics inhibit M3 receptors on sweat glands → decreased sweating → hyperthermia

Question 27

antimuscarinics decrease

Answer 27

antimuscarinics decrease salivation and lacrimation → dry mouth and eyes

Question 28

antimuscarinics cause

Answer 28

antimuscarinics cause mydriasis and cycloplegia → blurred vision

Question 29

antimuscarinics cause mydriasis

Answer 29

antimuscarinics cause mydriasis → decreased outflow of aqueous humor → acute angle closure glaucoma

Question 30

antimuscarinics cross

Answer 30

antimuscarinics cross the BBB and antagonize central M1 receptors → sedation, agitation, hallucination, coma (especially in elderly patients)