Preop

Question 1

What cells release endogenous histamine?

Answer 1

• Basophils & Mast cells

Question 2

What would be used to treat drug-induced histamine release?

Answer 2

• H1 & H2 antagonists

Question 3

Histamine-1 receptor activation can mimic these other receptor types.

Answer 3

• Muscarinic
• Cholinergic
• 5HT3
• α-adrenergic

Question 4

Histamine-2 receptor activation can mimic these other receptor types?

Answer 4

• 5-HT3
• β-1

Question 5

What are the side effects of H1 antagonists?

Answer 5

• Drowsiness/sedation
• Blurred vision
• Urinary retention
• Dry mouth

Question 6

What are four examples of H1 receptor antagonists?

Answer 6

• Diphenhydramine (Benadryl)
• Promethazine (Phenergan)
• Cetirizine (Zyrtec)
• Loratidine (Claritin)

Question 7

What is the E ½ time of diphenhydramine?

Answer 7

7-12 hours

Question 8

What is promethazine’s primary use?
What is it’s E ½ time?

Answer 8

• Rescue anti-emetic
• 9-16 hours

Question 9

What are the black box warnings associated with promethazine?

Answer 9

• 2005: children under 2 shouldn’t take (resp depression)
• 2009 - Tissue extravasation injuries

Question 10

What is the dosing of promethazine and when would one expect onset to occur?

Answer 10

• 12.5 - 25mg IV
• Onset: 5 minutes

Question 11

Which H2 antagonist strong inhibits CYP450’s?

Answer 11

• Cimetidine

Question 12

What is the dose for cimetidine?
What is the renal dose?

Answer 12

• 150 - 300 mg IV
• 150 mg IV

Question 13

What is normal ranitidine dosing?
What is the renal dosing?

Answer 13

• 50 mg diluted in 20cc’s over 2 minutes
• 25 mg diluted in 20cc’s over 2 minutes

Question 14

Which H2 antagonist is most potent and has the longest E ½ time? What is this E ½ time?

Answer 14

• Famotidine: E½ = 2.5 - 4 hours

Question 15

What is the dose of famotidine?
What is the renal dose?

Answer 15

• 20mg IV
• 10mg IV

Question 16

How do proton pump inhibitors work?
What is the onset of action for proton pump inhibitors?

Answer 16

• Irreversible binding to H⁺ pumps preventing acid creation.
• 3-5 days for full result.

Question 17

What is pantoprazole dosing?

Answer 17

• 40mg in 100mL over 2-15 minutes

Question 18

What is the time of onset for sodium citrate?
How long does it last?
What is the dose?

Answer 18

• Immediate onset
• Loses effectiveness in 30-60min
• 15 - 30 mL PO

Question 19

What is the dosing for metoclopramide?
When should it be given?

Answer 19

• 10-20 mg IV over 3-5min
• 15-30 min prior to induction

Question 20

What is the dose of Droperidol?

Answer 20

0.625 - 1.25 mg IV

Question 21

What is the E ½ time of Ondansetron? Why is this relevant?

Answer 21

• 4 hours: dose must be given so that effect peaks towards end of the case.

Question 22

What is the normal dose of Ondansetron?

Answer 22

• 4 - 8 mg IV

Question 23

What is the normal dosing for dexamethasone? When would one consider giving more?

Answer 23

• 4 - 8 mg
• Consider 12mg if difficult airway or swelling exists.

Question 24

What is scopolamine dosing and where do the patches need to be applied?

Answer 24

• 140mcg priming & 1.5mg over the next 72 hours.
• Apply to post-auricularly or on the back

Question 25

How much of a bronchodilator reaches the lungs with an inhaler method of delivery?
How much does this decrease/increase with an ETT?

Answer 25

• Inhaler: 12% of drug reaches lungs
• ETT: 30-50% of drug reaches lungs