BZDs and N/V meds

Question 1

At which pH is Midazolam water-soluble? Lipid-soluble?

Answer 1

Water-soluble pH < 3.5 - Open ring
Lipid-soluble pH > 4.0 - Closed ring

Question 2

Midazolam (Versed):
pK
Peak
Elimination 1/2 Time
Vd

Answer 2

pK = 6.2
Peak: 20-30 mins (Peds), 5 minutes in adults
E 1/2 Time = 2 hours
Vd = 1-1.5 L/kg

Question 3

Active metabolite of midazolam?

Answer 3

1-hydroxymidazolam

Question 4

Midazolam sedation dose?

Answer 4

Peds: 0.25-0.5 mg/kg (Peaks in 20-30 mins)
Adults: 1-5 mg (Peaks in 5 mins)

Question 5

Midazolam induction dose?

Answer 5

0.1-0.2 mg/kg over 30-60 seconds

Question 6

Post-op Versed dose?

Answer 6

1-7 mg/hr

Question 7

Concerns for prolonged midazolam administration?

Answer 7

T-cell suppression

Question 8

Diazepam (Valium)
Onset
Peak
Elimination 1/2 Time
Vd

Answer 8

Onset: 1-5 mins
Peak: 1 hour (Adults), 15-30 mins (Peds)
Elimination 1/2 Time: 20-40 hours

Question 9

Valium active metabolites?

Answer 9

Desmethyldiazepam (lasts 48-96 hours) and oxazepam

Question 10

Diazepam (Valium) doses for…
Induction?
Seizures?

Answer 10

Induction = 0.5-1 mg/kg
Seizure = 0.1 mg/kg

Question 11

Why does valium burn upon injection?

Answer 11

It contains propylene glycol

Question 12

Lorazepam (Ativan)
Peak
Elimination 1/2 Time
Duration
Post-Op Dose

Answer 12

Peak: 20-30 minutes
E 1/2 Time: 14 hours
Duration: 6-10 hours
Dose: 1-4 mg

Question 13

List benzodiazepine duration of action from shortest to longest…

Answer 13

Midazolam < Diazepam < Lorazepam

Question 14

Romazicon (Flumazenil) is derived from…

Answer 14

1,4 imidazobenzodiazepine

Question 15

Romazicon (Flumazenil) dosage to reverse sedation? Complete reversal?

Answer 15

0.3-0.6 mg
Complete reversal = 0.5-1 mg

TXWES ref says: 0.2mg and 0.1mg q1min max of 3mg

Question 16

Romazicon (Flumazenil) onset? Duration?

Answer 16

Onset = 2 mins
Duration = 30-60 mins

Question 17

Diphenhydramine (Benadryl):
Class
Receptor
E 1/2 Time
Dose

Answer 17

Class: H1 Antagonists
Receptor: Vestibular
E 1/2 Time: 7-12 hours
Dose: 25-50 mg

Question 18

Diphenhydramine inhibits what reflex?

Answer 18

Oculo-Emetic Reflex

Question 19

Promethazine (Phenergan)
Class
Receptor
E 1/2 Time
Onset
Dose

Answer 19

Class: H1 Antagonsist
Receptor: Vestibular
E 1/2 Time: 9-16 hrs
Onset: 5 minutes
Dose: 12.5-25 mg

good for a rescue drug (active vomiting)

Additional receptors: H1, Dopaminergic, and alpha antagonists for antiemetic
antagonizes muscarinic and NMDA which contribute to sedation (from drugbank.com)

Question 20

Scopolamine Patch
Class
E 1/2 Time
Onset
Peak
Dose

Answer 20

Class: Anticholinergic, Musarinic antagonist
E 1/2 Time: 24-72hours
Onset: 4 hours
Peak: 8-24 hours
Dose: The priming dose is 140 mcg, then over the next 72 hours 1.5 mg is absorbed through the skin

Question 21

What is the normal dosage and duration of Na⁺ Citrate (Bicitra)

Answer 21

15 - 30 mls
Duration: 30-60min

Question 22

How does Bicitra work?

Answer 22

non-particulate neutralization of gastric pH

Question 23

What is the downside of Bicitra?

Answer 23

• ↑ Na⁺
• ↑ gastric volume
• ↑ gastric pH

Question 24

Non-particulate antacids neurtalize acids and consist of:

Answer 24

sodium, carbonate, citrate and bicarb based

Question 25

Particulate antacids are aluminum and magnesium based - aspirating this is just as bad as aspirating ____

Answer 25

Stomach acid

Question 26

What are the H2 antagonists used in the OR?

Answer 26

• Famotidine
• Ranitidine
• Cimetidine

Question 27

What is the most potent H₂ antagonist?

Answer 27

Famotidine

Question 28

What is the most common infection associated with long-term H2 antagonist use?

Answer 28

Candida Albicans

Question 29

What is the dose of Famotidine?

Answer 29

20 mg IV (1/2 dose for renal impairment)
ET1/2: 2.5-4 hrs

Question 30

What is a major downside to famotidine usage?

Answer 30

Inhibition of phosphate absorption → hypophosphatemia

Question 31

What is the major downside to cimetidine use?

Answer 31

CYP450 inhibition

Consider warfarin, phenytoin, TCA’s, etc..

Question 32

Dose of Cimetidine

Answer 32

150 - 300mg IV (1/2 for renal impairment)

Question 33

What is the dose of Ranitidine?

Answer 33

50mg diluted in 20ccs over 2 min (1/2 dose for renal impairment)

Question 34

What effects do PPI’s have on anticoagulants?

Answer 34

• Inhibited warfarin metabolism = ↑ INR
• Inhibition of Plavix = ↓ PLT function

Question 35

What is the IV dose of pantoprazole?

Answer 35

40 mg / 100 mls over 2 min
Onset in 1 hr

Question 36

What is the IV dose of omeprazole?

Answer 36

40 mg / 100mls over 30 min

Question 37

What is the PO dose of omeprazole?

Answer 37

40 mg → 3 hours prior to surgery

Question 38

PPIs decrease ____ and increase ____

Answer 38

• Decrease Gastric volume
• increase pH

Question 39

Metoclopramide (Reglan) is FDA approved for ____

Answer 39

Diabetic Gastroparesis

Question 40

Metoclopramide (Reglan) slows the metabolism of ____

Answer 40

Succinylcholine by decreasing plasma cholinesterase

Question 41

Metoclopramide (Reglan) Dose

Answer 41

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

Question 42

Droperidol Dose

Answer 42

0.625 -1.25mg

Question 43

Zofran receptor, dose, Et1/2

Answer 43

5HT3 antagonist
4-8mg
Et1/2: 4hrs

Question 44

Dexamethasone (Decadron)
Onset
Dose
Duration
When do you administer this?

Answer 44

Onset: 2 hours
Dose: 4-8 mg; Give more (12-20 mg) for airway trauma
Duration: 24 hours

Administer at start of case or 2 hours before the end of a long case