Anticholinergics

Question 1

What to anticholinergics do to muscarinic and nicotinic receptors?

Answer 1

• antagonize effects of Ach at muscarinic receptors
  
  • heart, salivary glands, GI and GU tracts
• exert little or no effect at nicotinic receptors
  
  • NM junction, autonomic ganglia

Question 2

Which are naturally occurring tertiary amines that are ionized, but lipophillic enough to cross the BBB?

Answer 2

Atropine and Scopalamine

Question 3

Which anticholinergic drug does NOT cross the BBB?

Answer 3

GLYCOPYRROLATE

Question 4

How does an anticholinergic drug fit inthe muscarinic receptors?

Answer 4

The cation portion can fit into the muscarinic receptor

Question 5

Anticholinergics are competitive antagonists. What do they do exactly?

Answer 5

• reversibly bind with muscarinic receptor, preventing Ach from binding
  
  • do not alter membrane
  • do not prevent release of Ach or alter it
• increasing Ach can overcome effect of the drug
• small doses may actually stimulate or receptors and decrease HR

Question 6

What are the 5 subtypes of muscarinic receptors and what are their specific functions?

Answer 6

M1:
- CNS and stomach—> H+ secretion
M2:
- lungs and heart—> Bradycardia
M3:
- CNS, airway, smooth muscle, glandular tissue—> salivation, bronchodilation
M4 and M5: weak CNS effect (not significant)

Question 7

How do the muscarinic cholinergic receptors vary in sensitivity?

Answer 7

M3

Question 8

What is the duration for atropine and glycopyrrolate?

Answer 8

IV duration = 30-60 min

May need to redose

Question 9

What are uses for anticholinergics?

Answer 9

• pre-op meds: sedation, antisialagogue, prevent vagal reflexes
• treat reflex mediated bradycardia
• combined with anticholinesterase drugs
• bronchodilation
• prevent motion induced nausea

Question 10

How do anticholinergics contribute to sedation?

Answer 10

• Assoc. with restlessness and somnolence
• delayed awakening, esp in elderly
• inhaled anesth. Potentiate CNS effects
• reverse with physostigmine

Question 11

How does scopalamine compare to atropine in regards to sedation?

Answer 11

Scopalamine is 100xs more potent than atropine to decrease activity of reticular activating system (RAS)
* amnestic
Atropine: increased incidence of memory deficits compared to glycopyrrolate, delayed arrousal in 1st 30 min after end of anesthesia when reversed with atropine/neo

Question 12

How do the anticholinergics differ in the anti-sialagogue effect?

Answer 12

• scop. 3xs more potent than atropine
• glycopyrrolate 2xs more potent than atropine and longer duration
  Scop > glycopyrrolate > atropine

Question 13

How are anticholinergics usually used to prevent vagal reflexes?

Answer 13

• frequently used in pediatrics <1 year to blunt vagal reflex associate with laryngoscopy for intubation
• usually give IV after mask induction

Question 14

What is the drug of choice in bradycardia?

Answer 14

ATROPINE
Blocks effects of Ach on SA node
Most evident on young adults
(Scop and glycopyrrolate less effective at equivalent doses)

Question 15

Anticholinergics prevent ______________________________ effects of AchE.

Answer 15

Parasympathomimetic

- combine with AchE to reverse NMB drugs

Question 16

What is the bronchodilation (M3) effect due to?

Answer 16

Due to antagonism of Ach effects on airway smooth muscle

*** decreases airway resistance and increases dead space in asthma and chronic bronchitis (spirits and Atrovent)

Question 17

How are anticholinergics used to prevent motion- induced nausea?

Answer 17

Transdermal scop patch: apply 4 hours prior to need
S/e: sedation, mydriasis, dry mouth, localized irritation
(Also used for hiccups, cold remedy, anti-gastric [H+] secretion, biliary and smooth muscle relaxant

Question 18

What are s/s of anticholinergic OD?

Answer 18

Anti rest and digest

** CAN’T SEE, CAN’T PEE, CAN’T SPIT, CAN’T SHIT **

Question 19

What is the treatment for anticholinergic OD?

Answer 19

Physostigmine—> May need repeat doses

Question 20

What is Suggamadex for?

Answer 20

• reversal of amino-steroids (primarily vecuronium and rocuronium)
• Bind contents of Roc and take it away
• hydrophobic center, hydrophilic exterior

Question 21

What is the t 1/2 of Suggamadex?

Answer 21

2 hours

Not protein bound

Question 22

What area side effects of Suggamadex?

Answer 22

• anaphylaxis in 0.3%
• bradycardia
• > PTT/PT/INR up to 1 hour
• > 10% N/V, pain,hypotension, HA
• not studied yet in renal pts

Question 23

What is the most common cause of PONV?

Answer 23

Neostigmine

Question 24

After Suggamadex is used what do you need to counsel your pt to do?

Answer 24

Use second form a birth control for 1 week d/t decreased efficacy of oral contraceptives