Benzos Flashcards Preview

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Flashcards in Benzos Deck (22):
1

Benzos MOA (all the same)

Potentiate binding of GABA to GABA-A receptor, facilitating the opening of Cl- channels. This in turn hyperpolarizes the cell, decreasing excitability.

2

Benzos uses (all the same)

Anxiolysis

Sedation

Anterograde amnesia

Spinal level muscle relaxation

Anticonvulsant

3

Benzos specific antagonist

Flumazenil

4

Diazepam (Valium) kinetics

Highly PB, highly lipid sol., large Vd, easily crosses BBB/placenta. Rapid onset.

CYP450 metab., urine excretion. E1/2t 21-37 hours. Least potent benzo.

3 active metabolites- desmethyldiazepam most active, lasts 48-96 hours.

Painful injection.

5

Diazepam SE

Decrease CBF, CMR02. Cerebral CO2 response intact, but curve is flattened. Non-isoelectric EEG. Neuroprotective.

Decrease SVR, BP, CO with induction dose.

Decrease RR and TV at induction dose or with opioids.

Depresses deglutition reflex.

Largely CV stable, does not attenuate SNS response to DVL.

6

Diazepam CI/Cautions

Early pregnancy

Glaucoma

Hypersensitivity

Decrease dose in renal/liver impairment

Large doses can cause very large drops in BP

Older pts very sensitive

Rare paradoxical excitement

7

Diazepam dosing

Premed- 0.2mg/kg IV or 10-15mg PO

Induction- 0.5-1mg/kg IV

8

Midazolam (Versed) kinetics

90-98% PB, highly lipid soluble, rapidly crosses BBB/placenta. Rapid onset. Water soluble prep.

CYP450 metab., urine excretion. E1/2t 1-6hrs. Redose in 5 min increments.

1 active metabolite- hydroxy midazolam. 50% as potent.

9

Midazolam SE

Decrease CBF, CMRO2. Cerebral CO2 response intact, but flattened. Neuroprotective, non-isoelectric EEG.

Decrease in SVR, BP at induction dose. CO remains unchanged. Largely CV stable.

Dose dependent resp. depression. Decrease in RR and TV with opioids.

Does not attenuate SNS response to DVL.

10

Midazolam CI/Cautions

Older pts are very sensitive

Decrease dose in hepatic/renal impairment

Rare paradoxical excitement

11

Midazolam dosing

Premed- 1-2.5mg IV (max 5mg) or 0.5mg/kg PO (max 20mg)

Induction- 0.1-0.2mg/kg over 60 seconds

12

Lorazepam (Ativan) kinetics

80% PB, highly lipid soluble, large Vd. Rapid onset IV, 2 hours for PO.

CYP450 metab., 80% unchanged in urine. E1/2t 10-20 hours.

Most potent benzo, no active metabolites, painful injection. Does not alter NMB dose.

13

Lorazepam SE

Decrease CBF, CMRO2. Neuroprotective. Non-isoelectric EEG. Cerebral CO2 response intact, but curve flattened.

Decrease in SVR, BP, CO.

Decrease in RR and TV with opioids.

Depresses deglutition reflex. Does not attenuate SNS response to DVL.

14

Lorazepam CI/Cautions

Decrease dose in hepatic/renal impairment

Older pts very sensitive

Rare paradoxical excitement

15

Lorazepam dosing

Premed- 1-4mg IV or 50mcg/kg PO

16

Flumazenil drug class

Imidazobenzodiazepine derivative

17

Flumazenil MOA

Competes with benzos for GABA-A binding. High affinity, highly specific.

18

Flumazenil uses

Reversal of benzos

Differential diagnosis of coma

19

Flumazenil kinetics

50% PB, Vd 0.5L/kg, 1-2 min onset, 2-10 min peak, DOA 30-60 min. Painful injection.

Hepatic metab., urine excretion. E1/2t 60 min (shorter than most benzos)

20

Flumazenil SE

Dizziness, sweating, HA, N/V, vision changes

Agitation, depression, confusion

HR, BP unchanged.

21

Flumazenil CI/Cautions

Hypersens.

Do not use in any seizure disorder!

22

Flumazenil dosing

0.2mg IV, wait 2 minutes

Repeat 0.1mg IV, wait 1 minute, repeat to a max of 3mg