Autonomics: Anti-Muscarinics

Question 1

What is signified by the mice parking in reverse?

Answer 1

Muscarinic antagonists reversibly block muscarinic receptors

Question 2

What is the effect of anti-muscarinics on DUMBBELS?

Answer 2

Anti-Muscarinics block the muscarinic effects of DUMBBELS

Question 3

What is the effect of anti-muscarinics on the eyes?

Answer 3

Anti-muscarinics cause pupillary dilation (mydriasis) and cyclopegia (inability to accommodate the lens for near vision)

Question 4

What is scopolamine used for?

Answer 4

Motion sickness

sailor outfit

Question 5

How are anti-muscarinics like scopolamine able to treat motion sickness?

Answer 5

The cross the blood-brain barrier and inhibit central M1 receptors

Question 6

What is the effect of anti-muscarinics on the heart?

Answer 6

Anti-muscarinics block parasympathetic activation of M2 receptors on the SA and AV nodes, thus increasing HR and increasing AV conduction

(Elevated heart watch)

Question 7

Due to their effects on the M2 receptors, what are anti-muscarinics useful for as a treatment?

Answer 7

Useful in the treatment for bradycardia and heart block

Question 8

What are the two main M3 antagonists?

Answer 8

Ipratropium and Tiotropium

Question 9

What are the inhaled antimuscarinics used for?

Answer 9

Useful in the management of COPD. They antagonize M3 receptors, leading to bronchodilation and decreased secretions

Question 10

Which inhaled antimuscarinic lasts longer?

Answer 10

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

(Long lasting TIO smoke rings)

Question 11

What is Oxybutynin, and what is it used for?

Answer 11

It is an M3 muscarinic antagonist used to relieve bladder spasm after urologic surgery

(ox butler pouring water)

Question 12

What is Tolterodine, and what is it used for?

Answer 12

It is an M3 muscarinic antagonist used in adult urinary incontinence

(turtle butler pouring glass of water)

Question 13

Which two drugs treat incontinence, and what is their MOA?

Answer 13

Tolterodine and Oxybutynin

Antagonize M3 receptors, thus relaxing smooth muscle in ureters and bladder wall

Question 14

What symptoms of Parkinson’s are treated by anti-muscarinics?

Answer 14

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

Question 15

What are the two main M1 muscarinic antagonists?

Answer 15

Benztropine and Trihexyphenidyl

Question 16

Why are anti-muscarinics used to treat the side effects of antipsychotics?

Answer 16

Antimuscarinics are effective in treating extrapyramidal effects such as dystonia, akathisia, parkinsonism

(extra-parking cone)

Question 17

What are the adverse effects of the anti-muscarinics?

Answer 17

1. Hot as a Hare (inhibit M3 receptors, decreased sweating)
2. Dry as a Cracker (Decrease salivation and lacrimation)
3. Blind as a Bat (Mydriases and Cycloplegia)
4. High Pressure as a Kettle (Decreased outflow of aqueous humor leads to acute angle glaucoma)
5. Mad as a Hatter (Cross BBB and lead to sedation, agitation, hallucination, coma)