Sedatives/Hypnotics Flashcards
first recorded parenteral agent to produce a hypnotic state
Christopher Wren
1657
injecting an aqueous opium solution into a dog
first hollow needles
Francis Rynd
1845
injected a morphine solution around nerves to treat neuralgia
Why were hollow needles significant?
could now be sterilized
instead of using porcupine needles lol
first recorded IV anesthetic
chloral hydrate
Pierre Ore’
1872
IV administration of inhalational anesthetics
unsuccesful
changed everything in the early 1900’s
specific agents
barbiturate testing
opened the era of IV anesthesia
first administration of thiopental in 1934
When was ketamine released?
1970
“ketamine: hallucin8ing is very 70s”
When was etomidate released?
1974
When was midazolam released?
mid 70’s
most used benzo in anesthesia
Midazolam
T/F
inhalationals are the preferred anesthetic
False
IV preferred
partially d/t less equipment needed
When was propofol released in its current form?
1986
Diprivan
problems with formulation d/t its high lipid solubility
Drugs take about ____ years to bring to market, costing about ____ dollars
10-15 Y
~1 billion
T/F
“Sedative/Hypnotics” accurately describe the class of medications it encompasses.
False
old terms
not specific
Sedative
mild suppression of arousal and behavior
slight decrease in alertness and response to stimuli
T/F
Sedatives produce certain degrees of CNS depression, but not anesthetic levels.
True
Hypnotic
pronounced sedative effects
induction of sleep
T/F
Sedatives can cause sleep in the proper dose
False
hypnotics cause LOC in proper doses
T/F
Hypnotics can provide anesthesia level LOC
False
not quite anesthesia level b/c still arousable to strong stimuli
T/F
Most sedatives become hypnotics in higher doses
True
Sedative/Hypnotics
example agents
alcohols
barbs
BZD
misc (meprobamate, meathqualone, Droperidol, etomidate, propofol)
T/F
Alcohol is considered a sedative/hypnotic.
True
Why can’t ethanol alone be used for anesthesia?
level that causes LOC can cause death
too many side effects
Chloral Hydrate is still often used in which pt population?
children
Thiopental was optimal for (short/long) duration cases.
short
T/F
Thiopental and methohexital are considered similar.
true
T/F
Pentobarbital & Phenobarbital are part of different families but have the same effects.
False
same family
different effx
T/F
Phenobarbital was once commonly used a sleeping pill, but not as common now d/t side fx.
False
Pentobarbital
Phenobarb: seizures, psych disorders
induces its own metabolism
phenobarbital
T/F
The phenobarbital dose for a chronic user may be fatal to a person who has never taken it before.
True
phenobarbital induces its own metabolism
body builds resistance
BZDs have largely supplanted the BARBs, except for ____
methohexital
T/F
BZDs can be the solo agent used in short procedures.
False
used as an adjunct
Use of preop BZDs (increases/decreases) anesthetic requirement.
decreases
produces some CNS depression
Known as Quaaludes
Methaqualone
T/F
Methaqualone is still available on the market.
False
heavy abuse caused issues in distribution
T/F
Sedative/Hypnotics’ MoA is similar, but not identical.
True
Sed/Hyps mainly act on _____.
polysynaptic pathways
Sed/Hyps usually fxn to _____.
increase presynaptic inhibition
T/F
Sedative/Hypnotics all lead to CNS depression.
True
Why is our understanding of sed/hyps limited?
it works in the brain
anything working in brain is hard to ID all mechanisms
T/F
Different brain areas have different levels of susceptibility
True
Most Sedative/Hypnotics are believed to enhance…
pre- and post-synaptic effects of GABA (gamma-aminobutyric acid)
polysynaptic pathways
go thru multiple nerves
monosynaptic pathways
one nerve going one place to another
We tend to block thses with compounds
interneurons
GABA is an (excitatory/inhibitory) (compound/NT) because it…
inhibitory
NT (neurotransmtr)
decreases the ability of depolarization
Sedative/Hypnotics Mechanism of action:
GABA ___ Augmentation
Ionophore
(ionophore = ligand gated)
How many GABA sites on the GABA receptor?
2
Which GABA binding site are we most concerned with?
GABA A
GABA receptors came from …
5 subunit protein structure
T/F
GABA receptors are quadrameric in structure.
False
pentameric
Cl- is higher in the (ICF/ECF)
ECF
Na is higher in the (ICF/ECF)
ECF
K is higher in the (ICF/ECF)
ICF
Ca is higher in the (ICF/ECF)
ECF
extremely small amount in ECF and ICF
At which voltage can Cl- no longer move into the cell?
-90
Na stops moving into cells @ which voltage?
-30/-40
When ICF is extremely (+/-), it is harder to depolarize.
negative
T/F
Cl- ions cannot flow into the cell if the ICF is at -70 mv.
False
the Cl gradient (ECF vs ICF) is so large, that it overcomes the repelling - charge from ICF
until about -90 mv
Depolarization occurs when membrane potential is closer to ___.
0
BZDs ___ GABA fxn by….
augment
increasing CNS depression
Lowering ICF voltage makes it (easier/harder) to depolarize.
harder
T/F
A single GABA molecule can open the channel completely.
False
need two! Two sites
T/F
A single molecule of GABA can bind and cause some Cl- to enter the cell.
True
not as much Cl- will enter as when 2 GABA molecules bind tho
How many GABA molecules need to bind to change the ionophores structure?
only 1
1 =changes structure; some Cl- influx
2 = full effect
T/F
most ionophores need 2 molecules to bind for full effect
True
T/F
Most brain pathways are excitatory.
False
inhibitory
Too much excitatory activity may result in…
excessive neuron firing
epileptic conditions
Picrotoxin
strong stimulant
prevents GABA from binding
epilieptic type/stimulatory effects
Anything blocking GABA causes…
epilieptic type/stimulatory effects (ie: picrotoxin)
T/F
GABA only acts when we introduce sed/hyps into the body.
False
GABA acts brain all the time by providing inhibition at certain times
T/F
The GABA A receptor complex spans the membrane.
True
allows Cl- to pass thru bilayer & enter ICF
T/F
The GABA A receptor complex is mostly composed of B-pleated sheets inside the channel.
False
Mostly alpha helices inside channel
Form the “mouth” of the GABA A receptor complex.
spiral helices
Ach receptors at the NMJ are ____.
ionphores
Twist more or less to open/close channel of GABA A receptor complex.
spiral helices
T/F
Glutamate is an inhibitory neurotransmitter.
False
Glutamate is an excitatory neurotransmitter
glutamate = excite
GABA = inhibit
voltage-dependent ionophoric system
Glutamate
Sed/Hyps works by (agonizing/antagonizing) the Glutamate Receptor.
antagonizing
NMDA glutamate receptor complex
Which ions to enter?
Which exit?
Calcium and Sodium IN
Potassium OUT
T/F
NMDA glutamate receptor complex works independently of the membrane potential
False
allows Ca & Na in; K out
depending on local membrane potential
T/F
Ketamine appears to act primarily at the PCP binding sites on the GABA A receptor complex
False
Which receptor has a QUADRAmeric structure (4 subunits)?
NMDA
Ca and Na entering cell causes (repolar/depolarization)
depolarization
they’re + ions
Ketamine and PCP both cause hallucinations. Why?
Ketamine and PCP act on same site = hallucin8 with ketamine
(gen class: Ketamine is an analog of PCP)
angel dust
PCP
glycine allows ___ to act properly
glutamate
Glycine vs. GABA
which is most present in the brain?
which is most present in the SC?
brain: GABA
SC: glycine
T/F
Nicotinic receptors have a pentameric structure.
True
Glycine receptor
Inhibitory neurotransmitter complex similar to GABAA
2 sites for glycine
2 phases of sleep (that we discussed)
Slow wave sleep (SWS)
Rapid eye movement sleep (REM)
Rapid eye movement sleep (REM)
skeletal muscles are relaxed (inhibited) and the eyes move back and forth rapidly.
Slow wave sleep (SWS)
EEG shows mainly high-voltage synchronous activity
How much of sleep is REM?
~25%
1-2 H
Hypnotic sleep differs…
SWS altered & shortened
REM depressed
Total sleep time longer
T/F
Without SWS, people can become psychotic.
False
REM
Which drug class is known to inhibit REM sleep?
BZDs
T/F
Hypnotics can produce longer, deeper sleep.
False
longer but not very deep
inhibited REM
Twitching/movement seen during REM sleep
Breakthrough
Barbiturates
Onset and duration of effect generally predictably based on…
lipid solubility (higher partition coefficient)
Barbiturates
more lipid soluble agents (higher partition coefficient) usually have the more ___ onset and ___ duration
rapid
shorter
Inhibits oxidative phosphorylation
BARBs
cell fxns requiring energy slows down
Slows down whole body
Overdoses with BARB sleeping pills
awaken thinking they didnt take pill
could happen multiple times in a night
OD
T/F
BARBs have a wider T.window than BZDs.
False
BZDs have wide TW; harder to OD
Barbiturates MoA
-Bind to GABAA receptor
-(diff site than BZDs)
-Decreases the dissociation rate of GABA
-increase Cl conductance
-inhibits excitatory glutamate AMPA receptors
-inhibits Ca mediated glutamate release
T/F
BZDs and BARBs bind to the same site on the GABA receptor.
False
they have separate sites
Barbiturates MoA
outside of GABA receptor
inhibits:
1) excitatory glutamate AMPA receptors
2) calcium mediated glutamate release
T/F
Barbiturates mimic the action of GABA at the GABAA receptor to the same extent.
False
mimicking is minimal
major effects require GABA
T/F
Barbituric acid has no sedative powers of the parent compound.
True
structure we get all BARBS from
Barbituric acid
Exists in keto and enol forms (tautomers)
Replacement of C-2 oxygen with sulfur results in (2)
thiobarbiturates
&
greater lipid solubility
Addition of various functional groups onto position ___ alters sedative/hypnotic properties
5
Addition of a ___ group at C-5 enhances anticonvulsant activity and produces ___.
phenyl
Phenobarbital
phenyl @ 5 = pheno
Addition of a ___ group to the ring N atom shortens duration of action and produces ___.
methyl
Methohexital
Methyl to N =methohex
which positions are 1, 2 & 5?
what are their significance?
sites of substitution
Which class exists in tautomer forms?
BARBs
Barbiturates by duration
Long: Phenobarbital
Intermediate: Pentobarbital & Secobarbital
Short/Ultra-short: Methohexital & Thiopental
T/F
Complications and side effects lead to the discontinuation of Thiopental by the FDA.
False
DC’ed by manufacturer
refused to sell to US b/c we use it to kill ppl
Position 5 increases …
lipid solubility/mvmt into tissues
T/F
Barbiturates are weak bases.
False
Barbiturates = weak acids
What is the basic form of BARBs?
sodium salt (carboxylate form)
BARBs are packaged as ___.
sodium salt, which is the basic form
(carboxylate form)
The ___ pH of BARB sodium salt solution makes it ____.
high
bacteriostatic
T/F
We can remove multiple doses of a BARB out of its packaging.
True
pH = bacteriostatic
however, only stable for a couple weeks or else precipitates
lipid soluble agents
__ onset due to rapid increase in ____ concentration, followed by rapid ___ to other body fatty tissues.
shorter
brain
redistribution
T/F
BARBs are lipid soluble.
True
As a drug redistributes, the brain [ ] (increases/decreases)
decreases
primary mechanism of cessation of action of lipid sol Rx in the brain
Redistribution (to fat)
What does this chart tell us?
Thiopental
brain uptakes the fastest
balances with plasma [ ]
moves into other tissues
brain [ ] drops
Fat [ ] increases as [ ] in all other compartments drop
Thiopental
As fat [ ] increases, [ ] in other tissues (increases/decreases)
decreases
Primary metabolic pathway for BARB metabolism is…
hydroxylation to inactive metabolites
(Phase I)
phenobarbital t1/2
86 hours
slowly metabolized
BARB metabolism
occurs to a larger extent in oriental populations
N-glucosylation
Potent inducers of the hepatic microsomal enzyme system
BARBs
BARBs can increase metabolic rates of drugs metabolized by ____. These include….
hepatic microsomal enzyme (CYPs)
oral anticoagulants, phenytoin, TCA’s
Hydroxylation is a Phase ___ reaction.
I
its a CYP
Your pt is taking phenobarbital regularly for epilepsy. For their anesthesia, you would use drugs that …
Use phase II/renal metab
Cerebral edema occurs when…
prolonged hypoxia
cell damage/death causes swelling
What can cause cerebral edema?
drowning
OD
ilicit drugs
How does cerebral edema cause an impedance to blood flow?
Brain swelling impinges upon bony structure
closes off blood flow d/t pressure
Do BARBs cross the placenta?
Yes
BARB is mostly Phase ___ metabolism.
I
BARBs are less used now b/c…
BZDs safer and equally effective
Drug interactions (enzyme induction)
Tolerance development
Greater abuse potential
Less CNS specificity than BZDs
BZDs advantages over BARBs
higher specificity
safer (wider T.window)
equally effective
BARBs primary use
-Therapeutic/diagnostic (psych)
-cerebral edema (surgery, head injury, cerebral ischemia)
-Antiepileptic
What causes BARB tolerance
enzyme induction (CYP)
T/F
BARBs offer extensive pain relief and muscle relaxation.
False
Repeated administration of thiopental
will fill the body’s storage sites (fats) and can lead to long duration of action
(already some in fat, less [ ] differential btwn blood and fat; does not go into fat as quickly
Additional doses = longer duration
Not so much on second dose)
T/F
Thiopental increases sensitivity to pain
True
lowers pain threshold
Thiopental can induce in ____
10-15 seconds
2-3 times as potent as Thiopental
Methohexital
Methohexital metabolism
primarily via P-450 oxidation
metab faster than thio
(due to less lipid solubility)
T/F
Thiopental is more lipid soluble than methohexital.
True
Which has longer effect?
Methohexital
Thiopental
Thiopental
methohexital = less lipid-sol
-metabolized faster
-redistribution
Methohexital is more potent than thiopental, but its effect is lost mainly d/t …
due to re-distribution (even though less lipid soluble)
Which has faster recovery?
Thiopental
Methohexital
Methohexital
metabolized faster (due to less lipid solubility) primarily via P-450 oxidation
BZDs were first introduced for the treatment of
anxiety
BZD properties (4)
sedative
antianxiety
anticonvulsant
muscle relaxant
T/F
BZDs can achieve hypnosis and unconsciousness in large doses
True
BZDs used to supplement or to induce and maintain anesthesia
Diazepam (VALIUM)
lorazepam (ATIVAN)
midazolam
1/2 L of midazolam vs diazepam
M: 1H
D: >24 H
T/F
BZDs are mostly metabolized via glucuronide conjugation.
False
Many = microsomal N-demethylation (diazepam)
some (oxazepam) rapidly via glucuronide conjugation.
Midazolam: microsomal hydroxylation
Midazolam metabolism
rapidly mainly via microsomal hydroxylation
T/F
Caution with liver Dz pts & BZDs
True
T/F
1/2 life determines how long the effects of a medication will last.
False
1/2 life of effect
T/F
Lorazepam (Ativan) does not undergo Phase I metabolism.
True
⭐️
BZD receptor site
specific receptor sites
GABA receptor α and γ subunits
CNS
(ONE BZD site
Has TWO GABA sites)
BZDs primarily affects cells in the ___
brain
BZD MoA
-α and γ subunits (GABA receptor; CNS)
-enhance GABA binding to its receptor
-more Cl- in
-hyperpolarization
-resistant to excitation
(Vs BARBs: decrease GABA dissociation rate)
T/F
BZD receptors are found only in post-synaptic regions in the CNS
False
almost exclusively
T/F
BZDs have minimal effects in other areas of the body other than the CNS.
True
(except effects caused via CNS control)
BZDs receptor is greatest in the ______ & areas associated with ____.
cerebal cortex
memory formations
T/F
BARBs cause amnesia
False
BZDs do
T/F
BZDs have a smaller side effect profile
True
Area responsible for memory/consciousness/thinking
Neo Cortex
T/F
Anesthetic agents work in a bottom-up fashion.
False
work top-down
Neo cortex to lower brain
T/F
neo cortex regulates breathing/autonomic fxns
False
lower brain/lizard brain
Benefits of anesthetics affecting neo cortex before lower brain
affects memory/consciousness/thinking
before breathing & autonomic fxns
What do patients forget when we give then BZDs in preop?
don’t remember things just prior to surgery (exposure to OR)
BZD
CV effects
mild
minor decrease BP & SVR
T/F
BZDs increases heart rate.
True
Heart rate may decrease or increase somewhat, probably reflexively
depends on a person’s state
Rapid infusion of ____ risks ____, so resp support should be available.
Diazepam
transient apnea
(BZDs all carry risk of transient apnea, but rapid IV Diazepam especially)
BZDs induces relaxation of spastic skeletal muscle activity via ____
central inhibition
T/F
BARBs treat delirium tremens
False
BZDs
BZD Clinical Uses
Pre-op meds
Induction
sedation
Anticonvulsant
delirium tremens
Skeletal muscle relaxation
T/F
BZDs provide smooth muscle relaxation.
False
skeletal
T/F
BZDs are used as anesthetics.
False
T/F
BZDs cross the placenta well and leads to fetal depression.
True
Which BZD can lead to true physical dependance?
diazepam (long DoE d/t desmethyl metabolite)
“Diazepam dependance”
Flumazenil (Romazicon)
Competitive Benzo antagonist
IV
treat OD
almost immediate reversal
We must give Flumazenil (Romazicon) cautiously b/c…
give too much = seizure
astringent
Locally cause dehydration of cell protoplasm
Alcohol produces a cooling effect on skin due to
rapid evaporation
Applying alcohol & rubbing the skin
Rubbing: increases blood flow
alcohol: cools more blood at a time
T/F
Alcohol efficiently makes your body warmer in cold weather.
False
cutaneous vasodilation brings heat closer to surface = feel warmer
but
cold environment can suck this heat off you quickly
deadly
High dose alcohol injections near nerves
blocks conduction by decreasing Na+ and K+ conductance
but
we don’t do this b/c high doses needed
Alcohol bactericidal effect
ethanol penetrates lipid BL
increases fluidity of membrane
friction/shear tears bacterial membranes
T/F
Alcohol is considered a potent CNS depressant
True
Ethanol has a (wide/narrow) T.window as a general anesthetic.
narrow
why we dont use it for that
Raises pain threshold and causes euphoria
ethanol
Ethanol
resp effects
Depresses medullary sensing of plasma CO2
Long periods between respirations
T/F
Ethanol has anticonvulsant activity and may be used for these purposes if the patient is unresponsive to other means.
False
Anticonvulsant at [ ]s that depress other CNS functions
T/F
Ethanol causes cardiac depression by both central and direct mechanisms at high plasma [ ].
True
cardiac depression
central & direct
T/F
Ethanol can damage your muscles.
True
Small doses: increase work ability via central mechanisms
larger doses: decrease work; directly damage
T/F
Ethanol [ ] 10% and higher increases gastric blood flow and secretions
False
20%
What causes vomiting from ethanol?
large ingestions due to local irritant effect (gastric irritation and erosion)
Why do alcoholics have problems with fatty livers?
Increases synthesis of fat in liver
Cirrhosis seen in (short/long) term abuse
long
____ [ ] ethanol suppresses appetite.
high
Ethanol metabolism
ethanol –alcohol dehydrogenase–> acetaldehyde
alcohol dehydrogenase
liver enzyme
contains zinc
requires NAD cofactor
Acetaldehyde metabolism
using aldehyde dehydrogenase
becomes acetic acid
T/F
acetaldehyde is an energy source
False
acetic acid
T/F
Methanol is converted via same enzymes as ethanol.
True
Give ethanol drip for methanol poisoning
Occupies eznymes for methanol metab and use for ethanol instead
Excrete methanol in urine
Using alcohol dehydrogenase, methanol becomes _____ . It then becomes ____ using the enzyme ____.
formaldehyde
formic acid
aldehyde dehydrogenase
T/F
Ethanol can cause blindness in a dose of 15 ml.
False
METHanol
Formic acid cannot be used by the body, and its build up causes…
acidosis, which can be fatal
fomepizole (Antizol)
inhibitor of alcohol dehydrogenase
may replace ethanol use
resistance d/t cost = longer stay using ethanol drip
Why is making alcohol yourself dangerous?
methanol is produced in the process
Why is alcohol high in calories?
converted directly to acetic acid, an energy source
Which is most potent?
Zaleplon (Sonata)
Zolpidem (Ambien)
Eszopiclone (Lunesta)
Zaleplon (Sonata)
Zolpidem (Ambien)
Eszopiclone (Lunesta)
have similar action to ____ in action on ____ receptor complex
BZD
omega 1 portion of GABA A receptor (on alpha 1 subunit)
governs anti-anxiety and anticonvulsant effects
weak alpha-2 agonist
What did these medications have over BZDs for sleep?
Zaleplon (Sonata)
Zolpidem (Ambien)
Eszopiclone (Lunesta)
did not interfere with tomorrow’s activities
vs. “benzo hangover”
Which medications’ side fx included sleep eating/driving?
Zaleplon (Sonata)
Zolpidem (Ambien)
Eszopiclone (Lunesta)
the first hollow needles were used to treat
neuralgia using a morphine solution
Release date (earliest to latest):
Thiopental
midazolam
propofol
etomidate
ketamine
1934: thiopental
1970: ketamine
1974: etomidate
1975: midazolam
1986: propofol
TKEMP
Sedative
cause mild suppression of arousal and behavior, and a slight decrease in alertness and response to stimuli
Hypnotic
- pronounced sedative effects (ex: inducing sleep)
- usually arousable by strong stimuli (ie pain)
Most hypnotics are…
-most agents are sedatives given in larger doses
Which BARB was used as a sleeping pill?
Pentobarb
Which BARB induces its own metabolism?
Phenobarb
doses for chronic user could be fatal to novel user
Misc. category of Sed/hyps
Meprobamate
Methaqualone
Droperidol
Etomidate
Propofol
T/F
Most anesthetic agents work via same mechanism as the sed/hyps.
True
Most act mainly on
polysynaptic pathways (interneurons)
goes thru multiple nerves to get one place to another
more nerves = more receptors = greater chance drug can inhibit
presynaptic inhibition
2 methods:
1) NT released acts on receptor on presynaptic membrane to shut off/reduce release
2) neuron impinges on another (at terminal, axon, etc) to prevent signal passage
Can help control amount of NT released
presynaptic inhibition
SNS can shut off PNS via
presynaptic inhibition
T/F
Most sed/hyps work by inhibiting excitatory signaling via post-synaptic inhibition.
False
pre synaptic
T/F
Similar receptors in the brain work the same throughout the brain.
False
the different areas of the brain respond differently to the same compound, even if the receptors are similar
most are believed to enhance
the pre- and post-synaptic effects of GABA (gamma-aminobutyric acid)
ICF usual voltage
-50 to -70 mv
Cl influx brings ICF voltage to ____ mv. At this voltage…
-90
no more Cl- can flow in; repulsive force too strong
GABA receptors are located
between A1 and B2 subunits
prevents GABA from binding
Picrotoxin
T/F
90% of brain mechanisms are inhibitory.
True
T/F
the BZD site only allows antagonists to bind.
False
T/F
Steroids can augment GABA fxn.
True
Does ethanol excite or inhibit?
affects both “evenly”
but since most of brain is inhibitory, the inhibitory processes are affected the most
“drinking diminishes inhibitions”
the GABA receptor complex is similar to
ACh at the NMJ
both ionophores & pentameric
Glutamate acts at which receptors?
NMDA
AMPA
NMDA receptor structure
voltage-dependent ionphoric system
QUADRAmeric structure (4 subunits)
different than GABA ionophore!
Ways we can control ion passage thru channel
change charge at both ends of the channel (will repel/attract)
change diameter of channel
Ketamine MoA
primarily at PCP binding sites on NMDA glutamate receptor complex
blocks Calcium entrance → blocks excitation
similar to GABA and allows glutamate to act properly
glycine
T/F
Glycine attaches the the NMDA glutamate receptor allosteric site to alter Ketamine’s ability to bind and block Ca.
false
glycine has its own site
other ligands can bind to allosteric site and cause this effect tho
increased K outflow will cause
hyperpolarization (losing + charge)
the different mechanisms of action (7)
-GABA Ionophore Augmentation
-Glutamate Receptor Antagonism
-Two-pore domain K leakage channel activation
-Glycine receptor augmentation
-Sodium and Calcium ionophore inhibition
-Nicotinic ACh receptor inhibition
-Opiate Receptors
Sodium and Calcium ionophore inhibition
block these + ions that depolarize
Nicotinic ACh receptor inhibition
blocks action at NMJ
muscle relaxation
esp BZDs
nerves that go to skeletal muscle are ___ in nature
cholinergic
uses NT ACh to start contraction
using nicotinic ionophore (pentameric)
T/F
The muscle relaxant effect seen esp from BZDs is d/t muscarinic ACh receptor inhibition.
False
Nicotinic ACh receptor inhibition
T/F
Some sed/hyps act on opioid receptors
True
T/F
A dream (REM sleep) in which you’re running uses the same pathways as if you’re actually running IRL.
True
the brain inhibits the motor pathways during sleep; twitches = breakthrough
Long-term BZD & sleeping pill use affects sleep by…
Which- leads to…
inhibiting REM sleep
developing certain psychiatric disorders
REM sleep deprivation = psychotic
T/F
Hypnotics prolong sleep and enhance overall sleeping
True
but
not very deep
REM inhibited
Sleeping pills now vs back then
50’s/60’s: BARBs
now: BZDs d/t wider T. window
T/F
The primary effect of BARBs is their inhibition of oxidative phosphorylation.
False
BARBs do this, but isn’t primary effect
primary effect:
Bind to GABA receptor
Decrease dissociation of GABA
increase duration of action of GABA
increase chloride conductance
conductance
movement of ions thru a channel
Which position affects lipid solubility and DoA?
5
How do we achieve salt form of BARBs?
Remove H+ and replace with Na+
Na+ attaches to O-
O-[Na+]
What happens when we draw up additional doses from the same vial? (BARBs)
inserts air:
CO2 dissolves in water –> carbonic acid
H ions protonate –> back to (weak) acid form (RCOOH)
BARB structure can precipitate out (its no longer ionized)
&
decrease bacteriostatic effects
RCOOH vs RCOO-
which is water soluble?
RCOO-
ionized
(will make solutions basic; mechanism used to make BARB into salt form)
Use of BARBs in the Wada speech test
inject BARB into either L or R carotid
garbled speech = dominant language hemisphere
shows us which side NOT to use when doing NeuroSx
BARB coma mechanism
decreases [O] phosphryltn > decreased metabolism > decreases swelling
gives tissues time to heal
reduces swelling (which causes ichemia)
Should BARBs be used in pregnancy? why?
avoid
fetal elimination slower than mom’s
T/F
BZD receptors are found in fewer places than BARBs.
True
BZD have higher specficity
T/F
redistribution is an alteration of duration.
False
alteration of effect
Which causes greater skeletal muscle relaxation?
BARBs
BZDs
neither
BZDs
Oxazepam
use
metabolism
sleep indxn
eliminated rapidly primarily via glucuronide conjugation (phase II)»_space;> much shorter HL
Should we give BARBs with BZDs?
No
BARBs induce CYP 450 (increased metab)
BZDs mostly use this system for metabolism
T/F
Extended use of Versed may result in a -longer duration of effect d/t higher levels of inactive glucuronide.
True
high [ ] can increase duration of effect
also can happen in RF
Midazolam –> 1-Hydroxymidazolam
is what type of rxn?
hydroxylation
T/F
If a metabolite has Double the HL & half potency => doubles duration of effect
False
Double HL but half potency = extends effect but not greatly
Shorter DoE of all BZDs
Midazolam (even tho Lorazepam does not have active metabolite)
Region of brain distinctive to humans
neo cortex
T/F
Amnesia effect of BZDs is considered beneficial
True
decreases anxiety for future procedure bc they don’t remember the scary OR
Where do BZDs act?
interface of the α and γ subunits of the GABA receptor in the CNS
T/F
BZDs will decrease BP to the same extent as propofol.
False
BZDs do not drop BP as much
Drug of choice for status epilepticus
Diazepam
T/F
BZDs are contraindicated in pregnancy
False
cross placenta; fetal depression
but
can be used
Ethanol is ____ soluble
lipid
penetrates into lipid bilayer
increases fluidity
When are Ethanol’s effects greatest?
“up-swing” of the plasma [ ] curve
On downswing, the brain becomes accustomed to the alcohol, and we can perform the same task at higher blood [ ]
(Same effect/outcome has lower [ ] on upswing vs downswing)
T/F
acetic acid can greatly affect the body
False
formic acid; can lower pH; hard to remove
body mechanisms quickly removes acetic acid
(enters Krebbs cycle)
How is methanol eliminated?
urine
Z class of sed/hyps
Zaleplon (Sonata) – potency = 1
Zolpidem (Ambien) – potency = 1
Eszopiclone (Lunesta) – potency = 7X
T/F
Zaleplon (Sonata)
Zolpidem (Ambien)
Eszopiclone (Lunesta)
bind to alpha 2 receptors
False
they bind to the omega-1 portion of the GABA A receptor (on alpha 1 subunit)
“alpha 2 agonist” describes their actions on the SNS binding sites (norepi/epi type binding site)