Benzos Flashcards

1
Q

Flumazenil DOA? Metabolism?

A

30-60 min, meaning you may need to redose

Hepatic metabolism, renal excretion

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2
Q

Why is there a ceiling effect with benzos?

A

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.

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3
Q

Midazolam CV effects?

A

Cardio stable;

CO unchanged

Dec SVR at induction dosage

Dec BP from anxiolysis

Doesn’t attenuate laryngoscopy HR/BP changes

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4
Q

Benzodiazepine MOA

A
  • 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
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5
Q

Diazepam E1/2t?

A

Diazepam is ≈ day (20-50h)

Desmethyldiazepam is 2-4 days!

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6
Q

Lorazepam solvent?

A

Propylene glycol

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7
Q

Flumazenil (romazicon) dose?

reversal

(what about infusion?)

A
  1. 2 mg IV, wait 2 min,
  2. 1 mg IV subsequent doses at 60 sec intervals to

max total 3 mg

Infusion: 0.1-0.4 mg/h

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8
Q

Which benzodiazepine is most potent?

A

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

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9
Q

Structure of midazolam (versed)?

A

Water soluble preparation

Imidazole ring

(same compound that etomidate has)

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10
Q

Midazolam metabolism?

A

Extensive hepatic metabolism

ACTIVE METABOLITE: 1-hydroxy-midazolam

Conjugated and excreted in the urine

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

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11
Q

Diazepam metabolism?

A

Oxidation, n-demethylation to desmethyldiazepam (ACTIVE METABOLITE)

which is oxidized, conjugated, and excreted in the urine

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12
Q

Dosage of midazolam for…

Premedication peds, IV sedation adults, Induction

A

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

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13
Q

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

A

Lipid soluble

High PB

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14
Q

Flumazenil antagonizes what effects of benzos?

A

Antagonizes depression of ventilation and sedation

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15
Q

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

A

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

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16
Q

Where are GABAa receptors found?

A

On POST-synaptic neurons in the CNS

There are barely any GABA receptors outside the CNS

17
Q

What is the reversal for benzodiazepines?

A

Flumazenil (Romazicon)

Specific, competitive benzo antagonist with high affinity for benzo receptors

imidazobenzamine derivative

18
Q

Do benzos potentiate the neuromuscular blockade?

A

Nope

19
Q

Midazolam CNS effects?

A

Decreases CBF and CMRO2

Does NOT attenuate ICP response to laryngoscopy

Anticonvulsant and amnestic

20
Q

What is flumazenil (romazicon) a derivative of?

A

Imidazobenzodiazepine

21
Q

Benzodiazepine structure?

A

Benzene ring fused with 7-member diazepine ring

22
Q

Lorazepam metabolism and e1/2t?

A

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
Q

Do benzos induce hepatic enzymes?

A

Nope

24
Q

Midazolam respiratory effects?

A

Decrease in ventilation (dose dependent)

Hypoxemia and hypoventilation enhanced in presence of opioid

Depress swallow reflex

decreased upper airway activity

25
Q

Benzodiazepines 5 pharmacological effects?

A

Anxiolysis

Asleep (sedation)

Anterograde

Amnesia

Anticonvulsant

Muscle Relaxation- spinal

26
Q

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

A

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
Q

How does potency of midazolam compare to diazepam?

A

Midazolam is 2-3x more potent than diazepam

28
Q

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

A

DiVA

Diazepam, versed, ativan

29
Q

Lorazepam dosage?

premedication/po

IV

A

50 MCG/kg (max 4 mg) PO

1-4 mg IV

30
Q

Diazepam is prepared in what solvents?

A

Propylene glycol

Benzyl alcohol

Painful IV/IM injection

31
Q

GABA binds to ________

A

the 2 beta sites

32
Q

benzos bind to the _______

A
  1. gamma site
  2. GABA-A