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Flashcards in Sedative Hypnotics Deck (37)
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1
Q

How are benzodiazepenes metabolized?

A

Hepativ. P450 enzymes especially CYP3A4

2
Q

What barbiturate is excreted unchanged into the urine to a certain extent (20-30% in humans)? It also has an eliminiation half life of 4-5 days

A

Phenobarbital

3
Q

How can the excretion of Pb be hastened?

A

Alkalinize the urine because Pb is weakly acidic

4
Q

Where does Ramelteon act?

A

MT1 and MT2 melatonin receptors in the suprachiasmatic nucleus of the brain

5
Q

What receptors does busiprone act on?

A

D2 and 5HT1A

6
Q

How do benzodiazepenes and barbiturates affect liver metabolizing enzymes? State the difference

A

Barbiturates can increase the activity of these enzymes while benzos have no effect. So Pb can induce its own metabolism in the long run

7
Q

What type of GABA receptor do benzos and barbiturates bind to?

How about baclofen?

A

GABA A

GABA B

8
Q

How do the actions of Benzos and Barbs differ at GABA A?

A

Benzos increase frequency of opneing GABA gated chloride channels
Barbs increase duration

9
Q

What additional effects do barbiturates have that make them have more pronounced central depressant effects compared to benzos?

A

Depress actions of glutamic acid via binding to the AMPA receptor

10
Q

Identify the mediated actions of the different GABA A receptors.

A

alpha 1 sedation and amnesia
alpha 2 and 3 for anxiolysis and muscle relaxation
alpha 5 memory

11
Q

What kind of amnesia do benzos and barbs produce?

A

Anterograde

12
Q

What stages of sleep are reduced by benzos and barbs?

A

REM and Stage 4 NREM
Stage 2 NREM is increased

The general effects of benzodiazepines and older
sedative-hypnotics on patterns of normal sleep are as follows: (1) the latency of sleep onset is decreased (time to fall asleep); (2) the duration of stage 2 NREM (nonrapid eye movement) sleep is increased; (3) the duration of REM sleep is decreased; and (4) the duration of stage 4 NREM slow-wave sleep is decreased.

13
Q

What barbiturate is used for anesthesia owing to its high lipid solubility– great for induction?

A

Thiopental

14
Q

What is the most dangerous effect of sedative hyponotic drug doses?

A

Cardiovascular and respiratory collapse

15
Q

What is the expected adverse effect of benzos and barbs at doses meant to treat anxiety?

A

Disinhibition

16
Q

What is the antidote to benzo overdose and how does it act?

A

Flumazenil acting as a competitive antagonist at the GABA A receptor– blocking the effects of benzos and even the newer sedatives like zolpidem

17
Q

Why are zolpidem and other new sleeping pills like Zaleplon and Eszopiclone better than benzos?

A

Minimal change in sleep pattern. Also they have few amnestic effects and day after psychomotor depression or somnolence. Remember that Benzos decrease REM and slow wave stage 4 NREM sleep.

18
Q

What disease are barbiturates contraindicated in because of enhanced porphyrin synthesis?

A

Porphyria: Acute intermittent, variegate, symptomatic

19
Q

MOA of The newer hypnotics: Zolpidem, Zaleplon, Eszopiclone

A

Similar to Benzos– bind to GABA A– bind between the alpha and gamma receptors

20
Q

What is the advantage of busiprone over benzos in anxiety?

A

Minimal psychomotor impairment and no additive CNS depression

21
Q

Why do oxazepam and lorazepam have relatively short half-lives?

A

They are metabolized directly into inactive glucuronides VS diazepam, Flurazepam

THEY HAVE NO ACTIVE METABOLITES! LIKE ZOLPIDEM

22
Q

What is the elimination half life of phenobarbital?

A

4-5 days!

Diazepam 1-2 days half life

23
Q

What are the 3 characteristics of Ramelteon that make it ideal for use as a hypnotic substance?

A
  1. Reduced latency of persistent sleep with no effects on sleep architecture
  2. No rebound insomnia
  3. No significant withdrawal symptoms
24
Q

Why is busiprone NOT suitable for the management of acute anxiety?

A

Effects may take more than a week to become established

25
Q

How do barbiturates affect microsomal drug metabolizing enzymes?

A

Increased activity in stark contrast to benzodiazepenes and newer hypnotics like zolpidem

26
Q

T or F: Benzodiazepenes do not substitute for GABA but appear to enhance GABA’s effects allosterically without directly activating GABAa receptors or opening the associated chloride channels.

A

T

27
Q

T or F. Flumazenil also blocks the actions of barbiturates on the GABA receptor Cl channel.

A

F. It only antagonizes the actions of benzos and zolpidem

Recall that barbiturates bind in an area separate from the binding site of the benzos.

28
Q

What is an example of an inverse agonist at the GABA receptor? Acts by negative allosteric modulation of the GABA receptor function

A

beta carboline

29
Q

Which sedative hypnotics have no REM Rebound?

A

Zolpidem and then newer drugs

However, rebound insomnia occurs with both zolpidem and zaleplon if used at higher doses.

30
Q

What are the mechanisms of tolerance for sedative hypnotics?

A
  1. Increase in the metabolism of drugs
  2. Down regulation of receptors (bezodiazepenes)
  3. Pharmacodynamic tolerance: decrease in the responsiveness of the brain to the effects of the drug
31
Q

What is the advantage of benzos over SNRI and SSRI in the treatment of acute anxiety?

A

Benzos have a rapid onset of action.

32
Q

What kind of amnesia accompanies benzos?

A

Anterograde

33
Q

Which new hypnotic has value in those who awaken early in the sleep cycle? The drug acts rapidly and has a very short half life.

A

Zaleplon

34
Q

What are the three new sedative hypnotics?

A

Zolpidem, Zaleplon, Eszopiclone

35
Q

What sedative hypnotic drug is ABSOLUTELY CONTRAINDICATED against porphyria?

A

Baribiturates

Remember the Rrrrrrsss. baRbituRates and poRphyRias

36
Q

What agents block the GABA receptor serving as CNS stimulants?

A

These convulsant

drugs block the channel directly (picrotoxin) or interfere with GABA binding (bicuculline).

37
Q

How do new hyponotics affect sleep?

A

The newer hypnotics all decrease the latency
to persistent sleep. Zolpidem decreases REM sleep but has minimal effect on slow-wave sleep. Zaleplon decreases the latency of sleep onset with little effect on total sleep time, NREM, or REM sleep. Eszopiclone increases total sleep time, mainly via increases in stage 2 NREM sleep, and at low doses has little effect on sleep patterns. At the highest recommended dose, eszopiclone decreases REM sleep.