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Anesthesia Pharmacology > Benzos > Flashcards

Flashcards in Benzos Deck (45)
1

What is anxiety?


sustained state of apprehension and autonomic arousal in response to real or perceived threats.  Fear of suffering and death, loss of control, and frustration caused by the inability to communicate

2

What is the onset of midazolam


30-60 seconds

3

What are the symptoms of anxiety?


headach, insomnia, nausea, anorexia, dyspnea, palpitations, dizziness, dry mouth and chest pain.

 

Signs include diaphoresis, hyperventilation, tachycardia, etc

4

what is the duration of midazolam?


15-80 min

5

what is the peak time of midazolam?


3-5 min

6

What is the route and trade name for for lorazepam?


Ativan

iIV

7

What is the onset of Lorazepam?


1-2 minutes

8

what is the peak time of lorazepam?


20-30 minutes

9


what is the duration of lorazepam?


6-10 hours

10

What is the route for diazepam

po.  occasionall used in preop

11


What are the effects of benzodiapines?


Sedation

Anxiolysis

Anticonvulsant

Anterograde amnesia

12

Do benzodiazepines protect against the stress of intubation or provide anagesia?


no

Also not useful as an antidepressant or antipsychotic

13


How are benzo diazepines used clinically?


Relief of anxiety

Sedation and amnesia before and during medical and surgical procedures

component of balanced anesthesia

Treatment of epilepsy and siezures

Insomnia

Control of ethanol or other sedative-hypnotic withdrawal states

muscle relaxaition in specific neuromuscular disorders

diagnostic aids for treatment in psychiatry

14

What is the mechanism of action for benzodiazepines?


Benzodiazepines work in post synaptic neurons by binding to the GABAa receptor.  This receptor opens chloride channels and hyperpolarizes the neuron increasing the difference btw resting potential and action potential making firing less likely.

their action works in these areas:

Cerebral cortex>hypothalamus>midbrain>hippocampus>medulla>spinal cord

15

What is the effectif 20% of receptors are bound by a benzodiazepine?


axiolysis

16

What is the effect if 20-50% of receptors are bound by benzodiazepine?


sedation

17

What is the effect if 60% of receptors are bound by benzodiazepine?


uncosciousness

18

What is the preop dose of midazolam for kids?


0.5 mg/kg PO 30 minutes before

15 mg max

19

What is the IV sedation dose for midazolam?


0.5-4 mg IV load, followed by 1-7mg/hour

20

What is the dose of midazolam for IV induction of anesthesia?


0.1-0.2 mg/kg

21

What dose of Diazepam used for supression of seizure activity?

0.1 mg/kg

22


Are benzodiazepine subject to cross tolerance?


yes.  Alcohol also binds GABAa

23

How does hypoalbumenia affect benzodiapines?


Benzos are bound to protein 90-98%.  In the case of hypoalbunemia you have more free drug and an increased effect

24

How is midazolam metabolized?


liver oxidation by CYP450

25

How does alcohol use affect midazolam metabolism?


Alcohol increases tolerance due to GABAa ase well as leads to increased clearance

26

What is the active metabolite for midazolam?


there is none

27

How does age affect midiazolam?


in elderly >80yo -dysphoria, impaired cognitive function, and effects last long

28

How is versed for end stage renal disease?

versed metabolites are excreted in urine.  Because versed has no active metabolites, it will have no effect on these pts.

29


What effects do benzos have on the CNS?


decreased cerebral metabolic O2 requirement and decreased cerbral blood flow

No isoelectric EEG

No change in ICP

No evidence of neuroprotection

Potent anticonvulsant

30


What effects do benzos have on ventilation?


dose dependent decrease

31

What effects do benzos have on the CV system?


decrease BP and HR--minor

32


Do benzos cross the placenta?


YES

33


What are hepatic considerations for taking benzos


cross reactions with other drugs

age--elderly will not have as much blood flow to the liver

34

How do benzos work as anti convulsants?


ability ot facilitate the actions of GABA

(barbituates depress the CNS)

35

What is the dose of diazepam for lidocaine toxicity, DTs and status epilepticus?


0.1mg/kg IV

36


What is the pK of versed?


6.15

37

How does versed compare to Diazepam?


2-3x as potent

38

What are reasons versed is good for anesthesia?


Rapid onset

Short duration

Specific andtagonist

PO route

39


What are problems with Valium and Ativan in for anesthesia?

not water soluble-have preservative and additives and can cause thrombophlebitis and venous irritation

Active metabolites--this will increase effect in end stage renal disease

Slow onset

long duration

40

What is flunitrazepam?


rohypnol

41

What is flumazenil?


Specific competitive antagonist for benzos

42

What are potential problems of flumazenil?


Resedation-only has 30 minute duration

Withdrawl if chronically on benzos

43


How is flumazenil metabolized?


in liver

44

Wha tis the dosing for flumazenil?


0.1-0.2 mg IV repeated up to 3 mg

45

What percent of versed makes it to the BS after redistribution?


50%