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72 Cards in this Set

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General depressants which decrease CNS activity at low doses
Barbiturates
Decrease neural and skeletal muscle activity at higher doses
Barbiturates
Block activity in reticular activating system thereby producing sedation and inducing sleep
Barbiturates
Barbiturates block activity in the __ thereby producing sedation and inducing sleep
reticular activating system
Barbiturate with the longest half-life
Phenobarbital
Barbiturate with an intermediate half-life
Butabarbital
Barbiturates enhance __ receptor activity
GABAa
Barbiturates increase Cl- conductance as with benzodiazepines, however
through a separate site
inhibits GABA transaminase
Thiopental
Enzyme responsible for inactivation of GABA
GABA transaminase
At low doses, barbiturates block __ excitation
glutamate receptor-mediated
At high doses, barbiturates
Block K+ and Na+ channels
Net effect of a barbiturate is enhancement of __ and blockade of
inhibitory neurotransmission;
excitatory neurotransmission
Barbiturates are anxiolytic, but with substantial
drowsiness and ataxia
Barbiturates depress higher cortical centers, resulting in
euphoria
impaired judgment
giddiness
excitement
barbiturates have this effect on body temp
decrease it
barbiturates have this effect on monosynaptic reflexes
none
why don't barbiturates have an effect on monosynaptic reflexes
not centrally active muscle relaxants
do barbiturates have analgesic activity
no
Barbiturates depress respiration increasingly with
increasing doses
Very high doses of barbuiturates result in collapse of
vasomotor center
Barbiturates depress sympathetic ganglia activity which has this effect on bp
decrease blood pressure
barbiturates induce liver microsomal enzymes which
alters drug metabolism
Metabolism of barbiturates is achieved this way
in the liver by oxidation
barbiturates are generally well absorbed from
GI tract and muscle
Oxybarbiturate (e.g., phenobarbital) onset parallels
rate of absorption
Oxybarbiturate duration of action parallels
rate of elimination
Thiobarbiturate (e.g., thiopental) onset and duration of action related to
distribution
Rapid distribution to brain due to high lipid solubility thus rapid onset of action
thiobarbiturates
thiobarbiturates have rapid distribution to brain, but slower distribution to
muscle and fat tissues
Usefulness of barbiturates for anxiolysis is limited by
low selectivity
use of barbiturates as anxiolytics
Pre-anesthetic to reduce anxiety
barbiturates are effective hypnotics; however...
other medications are more selective
problem assoc with use of barbiturates for anticonvulsant activity
Respiratory depression
barbiturates decrease __ associated with surgery or head injury
cerebral edema
barbiturates are useful in treating __ arising from disease or poisoning
acute seizures
Idiosyncratic effects of barbiturates are seen mainly in these patients
geriatric and debilitated
Common ADRs of barbiturates are just extended __ effects
CNS depressant
Uticaria
hives
swelling in deep layers of skin
Angioneurotic edema
scaly skin disorder
Exfoliative dermatitis
lesion resulting from death of liver parenchymal cells, resulting in jaundice
Parenchymatous hepatitis
in a few cases, barbiturates result in __; a blood disorder involving loss of white blood cells
Agranulocytosis
dose of barbiturate which results in poisoning
5 – 10x therapeutic dose
dose of barbiturate which results in death
15 x therapeutic dose
Stupor or coma
Respiratory depression
Circulatory collapse
are all sx of
barbiturate toxicity
can be used as a supportive measure in treatment of barbiturate toxicity
Dopamine
Altered porphyrin synthesis
Porphyria
with barbiturates, tolerance develops to CNS depressant effects in this amount of time
within a few weeks
Chronic use of barbiturates has this effect on GABAa receptor
down-regulation
are barbiturates habit-forming?
yes!
dependance of an individual to barbiturates are both
psychological and physical
Withdrawal from barbiturates is more dangerous than withdrawal from
opiates
GABAA receptor down-regulation leads to __, which persists following drug withdrawal
elevated central cholinergic activity
The net effect of abstinence from barbiturates
CNS excitation
treatment for abstinence syndrome with barbiturates
Hospitalization and stabilization on lowest dose that prevents abstinence syndrome
Gradual withdrawal from barbiturates happens over this period of time
2 – 3 weeks
Substitution with __ to treat abstinence sydrome is not recommended
non-barbiturates
benzodiazepines and barbiturates are generally
sedative hypnotics
Chloral hydrate
Noctec
Methyprylon
Noludar
Glutethimide
Doriden
Ethinamate
Valmid
Methaqualone
Sopor® Parest® Quaalude
Ethchorvynol
Placidyl
Chloral hydrate is metabolized by
alcohol dehydrogenase
active metabolite of chloral hydrate
trichlorethanol
trichloroethanol is further oxidized to
trichloroacetic acid
Trichloroethanol half life is
8 hrs
Superior to barbiturates with respect to modifying sleep patterns, REM rebound
Chloral hydrate
When combined with ethanol, chloral hydrate rapidly and effectively
promotes sleep
chloral hydrate slows ethanol metabolism, thereby
enhancing effects of ethanol