Anxiolytics and Hypnotics Flashcards Preview

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Flashcards in Anxiolytics and Hypnotics Deck (43)
1

What is tranquilization?


the patient is relaxed, unconcerned with his or her surorundings and is FULLY FUNCTIONAL

2

What does a sedative do?


decreases activity, moderates excitement and calms patient although PATIENT IS AWAKE

3

What does a hypnotic do?


produces drowsiness and facilitates the onset and maintenance of sleep, but patient may be EASILY AROUSED

4

How are hypnotics different from general anesthetics?


when a patient is under general anesthetics they can't be aroused

5

What are barbiturates classified?


their mechanism of action is all the same, so they're classified by their duration of action:

ultra-short acting

short-intermediate acting

long acting

6

What are the characteristics of ultra-short acting barbiturates?

(i.e. why are they so fast acting, how is function terminated)


their half life is only minutes because they're very lipid soluble

they reach the CNS very quickly

termination of action is thorugh redistribution to muscle and other sites

7

What are two examples of ultra-short acting barbiturates?


thiopental (pentothal)

methohexital (brevital)

8


How long is the half life for the short-intermediate acting barbiturates? What does it depend on?


half-life is hours

depends on rate of metabolism

9


What is an example of a short-intermediate acting barbiturate?


secobarbital (seconal)

10

What is the half life for the long acting barbiturates? How?


days

very slow metabolism - can be excreted wholly or partially unchanged

11

What is an example of a long acting barbiruate?


phenobarbital

12

What tissues do barbiturates cause depression in?


produces reversible depression of ALL excitable tissue (nervous, smooth muscle, cardiac muscle)

CNS most sensitive

13


What barbiturate is selectively anticonvulsant, while the remainder are relatively unselective in their depression of the CNS?


phenobarbital

14

What are barbiturates affect on pain?


pain is the one function which is not impaired until unconsciousness

in fact, at small doses you have hyperalgesia!

15

What effects of barbiturates will develop tolerance and which won't>

tolerance developes for: mood, sedation and hypnosis

Not to anticonvulsant and lethal effects

16

With repeated use of a barbiturate, there is a ____ in the drug's therapeutic index.

Why is this really important public health-wise?


decrease

this is important because barbiturate shave the highest rate of accidental OD among drug abusers because of it.

17

What is the mechanism of the barbiturates?


it facilitates GABA- mediated neuronal hyperpolarization by Cl- inflow

specifically, they increase the duration the Cl- channels are open

it potentiates GABA's inhibitory effect on CNS function

18

When will respiratory and CV depression occur with barbiturates?


ONLY at toxic doses

19

What is the effect of barbiturates on liver metabolism?


barbiturates are inducers of drug metabolism

repeated exposure causes an increase in the liber's drug metabolizing activity, meaning the barbiturate will be broken down faster with repeated use

20

How are barbiturates administered?


oral - as sedative or anticonvulsant

IV - as anesthetic induction agent

NOT given IM because the solution is alkaline and will cause tissue necrosis

21

In what populations is barbiturate metabolism slower?


geriatric and neonates

22

In terms of barbiturate elimination, what effect will increasing urinary pH have?

What does this mean for barb OD treatment


weak acids are reabosrbed at low pH

so...if you increase urinary pH (make more basic), you get more drug excretion

this means that an OD of phenobarbital can be treated by administering sodium bicarbonate intravenously to elevate urinary pH

23

Why is the sodium bicarb trick only really successful for phenobarbital and not the other barbiturates?


phenobarb isn't really metabolized much before it's excreted

the others are

24

What symptoms occur in a barbiturate hangover?


it's basically extended CNS depression

disrotions in mood, impaired judgmenet and fine motor skills as well as intellectual performance

these effect smay be noticeable as long as a day after usage

25

What is paradoxical excitement with barbiruates and who does it occur in?


the patient will appear intoxicated

seen most often in geriatric and weakened patients

26

What are the 3 main clinical uses of barbiturates?


anxiolytic/hypnotic

anticonvulsant

anesthesia inducer

27


What are the other clinical uses for barbiturates that are less common?


1. combined with other drugs to manage GI disorders or asthma

2. combined with other drugs for analgesia

3. decrease cerebral edema form surgery, injury or ischemia

4. treat hyperbilirubinemia and kernictus in neonates via induction of hepatic metabolism

5. anxiolytic-sedative-hypnotic with alcohol withdrawal

28


What are the steps of effect with benzodiazepines?


1. tranquilization

2. sedation

3. hypnosis

(actually, the true nesthetic depth is never reached, awareness of pain persists, but anterograde amnesia does occur, creating the illusion of previous anesthesia)

29

Why do only some benzodiazepines block seizures and produce muscle relaxation?

some are partial agonists vs. full agonists

some interact with specifi GABAa subunit receptor combinations and not others

30

What is the effect of benzodiazepines on sleep?


decrease sleep latency (faster onset)

diminish # of awakenins

overall effect is an increase in total sleep time

(greatest effect in patients with short baseline of sleep, not in those who normally sleep well)

31

What is the mechanism of action for the benzodiazepines?


they faciliate GABA-mediated neuronal hyperpolarizaiton by increasing the frequency of Cl- channel openings

32

Unlike the barbiturates, what is the effect of benzodiazepines on systems other than the CNS?


really very little effect on anything otuside the CNS

33

Why are the pharacokinetics of the benzos as a group so complex?


most benzos have active metabolites

the duration of behavioral effects does NOT coincide with plasma half life of the parent compound because they're metabolized at such different rates

34

What sort of amnesia can be caused with benzos taken with alcohol or high doses?


anterograde - memory after the drug has been taken

this is why Rohypnol is a "date rape" drug

35


Which are safer in general, barbs or benzos?


benzos - they have a high therapeutic index and death is rare unless other drugs like alcohol are present

36

Although Benzo toxicity is rare, what drug can be given as a benzo receptor antagonist?


flumazenil (romazicon)

37

What is the mechanism of action for the non-benzodiazepine benzodiazepine receptor agonists?


they bind only certain subtypes of the GABAa receptor at the benzo binding site

38

What are the advantages to the non-benzo benzo-receptor agonists?


they have rapid onset

short duration with no residual effects upong wakening

slow tolerance development

39


What are three examples of the non-benzo benzo-receptor agonists?


zolpidem (ambien)

zaleplon (sonata)

eszoplicone (lunesta)

40

What is the mechanism of Ramelteon (rozerem)?


It is an agonist at the maltonin MT1 and MT2 receptors in the brain's suprachiasmatic nucleus - the body's master clock

41

What does Ramelteon do for sleep?


It regulates 24-hour circadian rhythms, including sleep-wake cycles

thus, is normalizes sleep without any adverse effects or formation of dependence or abuse!

42

43

What is the difference between pharmacokinetic and pharmacodynamic tolerance? Which do you see with barbiturates?

 

pharmacokinetic = dispositional (induction of metabolism means repeated administration will lead to lower blood concentration and smaller effect)

pharmacodynamic = cellular adaptation (a functional change in the cell itself such that it becomes less responsive to the drug)

WIth the barbiturates, for the first 10 days or so you'll se pharmacokinetic tolerance, but then blood concentration levels start staying constant. However at that point you get pharmacodynamic tolerance, so you still get a gradually decreasing effectiveness