Axinolytics Flashcards
benzodiazepams with long half lives
chlordiazepoxide diazepam prazepam cloraepate flurazepam
bzds with short half lives and no active metabolites
lorazepam
oxazepam
bzds with short half lives and active metabolites
alprazolam
triazolam
benzodiazepam antagonist
flumazenil
barbiturates
thiopental
anxiolytic
buspirone
other hypnotic
zoplicone
what is anxiolytic
calming
relief of anxiety
what is hypnotic
promotes drowsiness and onset and maintenance of sleep
what is the action site of bzds
GABA-A receptor
what is the gaba- a receptor and the structure
inhibitory transmitter in the brain
hetero-oligomeric glycoprotein with 2 alpha, beta subunits and 1 gamma subunit
how many isoforms of the alpha subunit
alpha 1- hypnotic
alpha 2-5- sedation and psychomotor effect
what does activation of gaba- a receptor do
chloride influx hyperpolarizes neurons and decreases neuronal activity
what do barbiturates do
bind to GABA-A receptor
increases the durationof channel opening events
GABA- mimetic at high concentrations
inhibit glutamate AMPA receptor
how can you increased the onset of CNS drugs
increase lipophilicity so cross BBB
lipophilicity of bzds
traizolam>diaepam > lorazepam, oxazepam
what therapeutic used are preferred for short acting bzds?
long acting?
short acting- hypnotic
long acting - anxiolytic
how are bzds excreted
kidney
who should you consider when using bzds
pregnant and breast feeding, can cross placenta and in milk
older patient becuase decreased liver function and patients with liver tissue
obese patienys bc redistributed to adipose tissue
how are barbiturates metabolized and the effects on the enzymes
metabolized in liver slowly
hepatic cyt-p450 inducers
therapeutic uses of bzds
anxiety relief treatment of insomnia sedation and amnesia before surgery treat epilepsy and seizure states muscle relaxtion in neuromuscular disorders control of ethanol withdrawal symptoms
what is used for acute anxiety and what is used for long term anxiety treatment
acute- bzds
long term- SSRI
stages of sleep
1: muscles relax
2: brain activity slows no eye movement
3/4: all eye and muscle movement seizes
rem: rapid eye movement
how are bzds used as hypnotics
decrease the latency to sleep onset and increase stage 2 sleep
decrease rem and slow wave sleep
why are bzds used over barbituates for sedative or hypnotic
safer becuase less CNS depression, wont cause coma
what is thiopental used for
used to induce amnesia, rapid induction adn clearance
adverse effects of bzds
drowsy confusion anterograde amnesia dizziness lethargy ataxia safe unless used with other CNS depressants
how does bzd tolerance occur
down-regulation of brain bzd receptors - pharmacodynamic
bzd withdrawal symtoms when are they more common
rebound anxiety
insomnia
restlessness
more common and severs in short half lives
why are bzds abused
effects similar to alcohol
available
tolerance and dependence associated with long term use
contraindications for bzd use
myasthenia gravis narrow angle glaucoma alcoholism severe sleep apnea pregnant or nursing
what is flumazenil used for
bzd competitive antagonist used to reverse CNS depressant effects of bzd overdose
what is a caution with flumazenil use
if bzds used for seizures may have rebound seizure
adverse effects of barbiturates
can cause cardiac and vascular depression low therapeutic index metabolic and pharmacodynamic tolerance severe withdrawal symptomes abuse no antidote
difference between metabolic and pharmacodynamic tolerance
metabolic- induces enzymes
pharmacodynamic- down regulation of receptors
what is the action sire of buspirone
partial agonist at serotonin receptor
presynaptic antagonist at presynaptic dopamine d2 receptor
pharmacokinetics of buspirone
rapid oral absorption
extensive first pass metabolism to form active metabolites
what is buspirons therapeutic use
relieve anxiety
takes over a week so not used in acute or panic disorder
contraindication for busporin
monoamine oxidase inhibtors
action site of zoplicone
GABA-A alpha 1 subunit
enhances gaba mediated neuronal inhibition
pharmacokinetics of zoplicone
rapidly absorped and metabolizes
therapeutic uses of zpoplicone
short term treatment of insomnia, increase stage 2 as well as stage 3/4
adverse effects of zoplicone
drowsiness, memory impairment, dizziness, fatigue