Benzos Flashcards Preview

Summer Pharm (2016) ** > Benzos > Flashcards

Flashcards in Benzos Deck (32):
1

Flumazenil DOA? Metabolism?

30-60 min, meaning you may need to redose

Hepatic metabolism, renal excretion

2

Why is there a ceiling effect with benzos?

Because all it can do is assist GABA to open the Cl- channels. After that, it can't do anything else to achieve any effects.

3

Midazolam CV effects?

Cardio stable;

CO unchanged

Dec SVR at induction dosage

Dec BP from anxiolysis

Doesn't attenuate laryngoscopy HR/BP changes

4

Benzodiazepine MOA

  • Facilitate action of GABA and GABA-A receptor, enhance affinity of GABA to the receptor (but DOES NOT activate GABA-A receptor)
  • This leads to Cl channels open, inc conductance, hyperpolarization of post-synaptic membrane, increased resistance of post-synaptic membrane to excitation

5

Diazepam E1/2t?

Diazepam is ≈ day (20-50h) 

Desmethyldiazepam is 2-4 days!

6

Lorazepam solvent?

Propylene glycol

7

Flumazenil (romazicon) dose?

reversal

(what about infusion?)

0.2 mg IV, wait 2 min,

0.1 mg IV subsequent doses at 60 sec intervals to

max total 3 mg

Infusion: 0.1-0.4 mg/h

8

Which benzodiazepine is most potent?

Lorazepam (ativan) It is 5-10x more potent than diazepam

9

Structure of midazolam (versed)?

Water soluble preparation

Imidazole ring

(same compound that etomidate has)

10

Midazolam metabolism?

Extensive hepatic metabolism

ACTIVE METABOLITE: 1-hydroxy-midazolam

Conjugated and excreted in the urine

Renal failure doesn't effect VD, E1/2t, or clearance

11

Diazepam metabolism?

Oxidation, n-demethylation to desmethyldiazepam (ACTIVE METABOLITE)

which is oxidized, conjugated, and excreted in the urine

12

Dosage of midazolam for...

Premedication peds, IV sedation adults, Induction

Premed peds: 0.25-0.5 mg/kg po (not on drug cards)

Peds po dose max 20mg IV

sedation adults (premedication): 0.5-5 mg IV or 0.04-0.08 mg/kg

Induction: 0.05-0.35 mg/kg over 30-60 sec

*Per drug cards, not powerpoint

13

Benzos are highly _____ (water/lipid) soluble and _____ (high/low) protein binding

Lipid soluble

High PB

14

Flumazenil antagonizes what effects of benzos?

Antagonizes depression of ventilation and sedation

15

What does it mean if a drug has a short effect site equilibration time?

It means that the effects on the brain occur promptly after IV administration

16

Where are GABAa receptors found?

On POST-synaptic neurons in the CNS

There are barely any GABA receptors outside the CNS

17

What is the reversal for benzodiazepines?

Flumazenil (Romazicon)

Specific, competitive benzo antagonist with high affinity for benzo receptors

imidazobenzamine derivative

18

Do benzos potentiate the neuromuscular blockade?

Nope

19

Midazolam CNS effects?

Decreases CBF and CMRO2

Does NOT attenuate ICP response to laryngoscopy

Anticonvulsant and amnestic

20

What is flumazenil (romazicon) a derivative of?

Imidazobenzodiazepine

21

Benzodiazepine structure?

Benzene ring fused with 7-member diazepine ring

22

Lorazepam metabolism and e1/2t?

Metabolites are INACTIVE

Metabolism effected by hepatic function and age E1/2t 10-20h

Slow onset, IV takes 20-30 min to peak, not used as often in OR

23

Do benzos induce hepatic enzymes?

Nope

24

Midazolam respiratory effects?

Decrease in ventilation (dose dependent)

Hypoxemia and hypoventilation enhanced in presence of opioid

Depress swallow reflex

decreased upper airway activity 

25

Benzodiazepines 5 pharmacological effects?

Anxiolysis

Asleep (sedation)

Anterograde

Amnesia

Anticonvulsant

Muscle Relaxation- spinal

26

Diazepam dosages for... premedication oral and IV; induction; anticonvulsant?

Premedication oral: 10-15mg

Premedication IV: 0.2 mg/kg (reduces MAC)

Induction: 0.5-1 mg/kg IV

Anticonvulsant: 0.1 mg/kg IV

27

How does potency of midazolam compare to diazepam?

Midazolam is 2-3x more potent than diazepam

28

What is the order of benzos from least to most potent?

DiVA

Diazepam, versed, ativan

29

Lorazepam dosage?

premedication/po

IV

50 MCG/kg (max 4 mg) PO

1-4 mg IV

30

Diazepam is prepared in what solvents?

Propylene glycol

Benzyl alcohol

Painful IV/IM injection

31

GABA binds to ________

the 2 beta sites

32

benzos bind to the _______

  1. gamma site
  2. GABA-A