Exam 4: Anxiety Pharmacokinetics Flashcards
drugs that relieve anxiety are
anxiolytic
- relieve tension, worry, stress
- produce calm relaxed state, without drowsiness!!, mental clouding, and incoordination
sedative-hypnotic drugs
CNS depressants
barbiturates, benzodiazepines, alcohol
-sleep aides/sedation - calms people down
-at high doses - CNS depressants induce coma and deah, respiratory depression
make people very tired!!!
benzodiazepines are used for what anxiety disorders
GAD, panic disorder, OCD, social phobia, alcohol withdrawal, acute situational anxiety
benzodiazepine trade name
valium, xanax
SSRIs are used for
social phobia, OCD, panic disorder, PTSD
what schedule drug are barbiturates
schedule II: pentobarbital -anesthesia
schedule III: butobarbital
schedule IV: luminal -anti-anxiety, sleep inducing aspects
high abuse and addiction liability dependent on lipid solubility
uses for barbiturates (4)
- surgical anesthesia
- sleep aid
- anti-anxiety
- anticonvulsant - used for seizures
barbiturate ROA
IV most common, also oral
short term: IV - surgical anesthesia
long-term: oral - anticonvulsant or antianxiety
intranasal common route for barbiturate abuse!
what is absorption of barbiturates dependent on
lipid solubility!
ultrashort acting have highest lipid solubility - get to brain fastest onset 10s-20min
long acting have lowest lipid solubility onset an hour to 12 hrs (ex: phenobarbital)
distribution of barbiturates
readily pass thorugh BBB and placental barriers, detectable in milk of nursing mothers
accumulation in skeletal muscle and adipose tissue (depot binding)
- these drugs do not work well in those obese bc there is lots of depot binding
- depot binding can be problem: at high levels when some gets stuck over time it leaks out into bloodstream
metabolism and excretion of barbiturates
-broken down in liver
INACTIVE metabolites excreted in urine
after chronic use what types of tolerance do you see
metabolic tolerance: cyp450 enzyme induction associated with inc drug metabolism, lower blood concentration of drug, and reduced drug effectiveness
cross tolerance: makes other drugs not work as well
pharmacodynamics of barbiturates (2)- what neurotransmitter involved
enhance GABA actions in CNS
-positive allosteric modulator: inc affinity of GABA A receptor for GABA, makes it more sensitive
they directly open Cl- ion channels in GABA A receptor without GABA present
- extreme sedation possible bc it acts as a false agonist for GABA
at higher doses what do barbiturates act as - pharmacodynamics
antagonists for AMPA and Kainate glutamate receptors
-for seizure disorders - it shuts down hyperexcitability
sedation is good in moderation- remember too high can cause respiratory depression
dangers of barbiturates: tolerance
-behavioral tolerance to some sleep-producing and anti-seizure effects of barbiturates
-respiratory depression does NOT show tolerance - reduced margin of safety due to rightward shift on curve
it does not effect the brainstem sedation - short window btw it being fun and causing respiratory depression
dangers of barbiturates - withdrawal and addiction
- they produce significant physical dependence and have high potential for abuse
- can’t quit cold turkey after chronic use, need to gradually come off to avoid rebound hyperexcitability and seizures like alcohol withdrawal
dangers in high doses of barbiturates
- poor coordination, slurred speech, life-threatening respiratory depression
- at its height of use, more than 15000 deaths/year in US were from barbiturate overdose
mild/moderate doses of barbiturates causes
nausea/vomiting/diarrhea drowsiness impaired cognition/attention/judgement slurred speech emotional dysregulation
serious doses of barbiturates effects
shock
coma
death
birth defects (prenatal exposure - crossing placental barrier)
what type of drug accounts for 2/3 of all medical prescriptions for psychoactive drugs
benzodiazepines
- 30% all anxiety disorders diagnoses treted with benzos
- over 40% of panic disorder pts prescribed benzos
what schedule drug are benzodiazepines
schedule 4 drugs
use patterns of benzodiazepines
women twice as likely to use than men
45% use or less than 30 days - short term going on aplane
80% of use is for less than 4 months
15% use is greater than 12 months