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Antianxiety & Hypnotic Medications
Psych
27
Medical
Graduate
10/25/2011

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Cards

Term
types of antianxiety drugs
Definition
-antidepressants (SSRIs, TCAs, MAOIs)
*Benzodiazepines
-Busirone
Term
pharmacologic actions of benzodiazepines
Definition
-relief of anxiety
-drowsiness or sedation
-skeletal muscle relaxation
-anticonvulsive activity
-anterograde amnesia

All from actions in the CNS at GABA-A receptors
Term
GABA
Definition
-has depressant acitivty
-synthesized in the presynaptic terminal, stored in vesicles, and released
-hyperpolarization from influx of chlorine into post-synaptic cell

-formed from a glutamate precursor (which is the primary stimulant int he brain)
-GABA in the primary depressant in the brain
Term
GABA-A receptor
Definition
-ligand gated ion channel for Cl
-antianxiety drugs we use are NOT direct GABA antagonists
-use drugs that POTENTIATE the actions of GABA
-these drugs act on different subunits of the GABA receptor to make GABA work better
Term
Barbiturate activity
Definition
make GABA work better by keeping Cl channel open for longer
Term
benzodiazepines activity
Definition
-makes GABA work better
-act at the interface between two of the receptors different subunits
-open/close the Cl channel rapidly
-shifts GABA dose response curve to the left
Term
CNS depression and antianxiety drugs
Definition
-level of CNS depressive effects increases with the relative concentration of drug
-barbituates increase to cause a marked level of CNS depression ultimately leading to death (with euphoria)
-benzo levels off and doesn't have as extreme effects, much safer
Term
absorption, metabolism, excretion
Definition
-relative rates of absorption, metabolism, and excretion differ markedly between drugs
-drugs are prescribed based on their pharmacokinetics
**greater lipid solubility leads to greater absorption and more rapid onset of action
**elimination half life is determined by metabolism
Term
lipophilicity
Definition
-more lipophilic drugs get into the CNS very fast, and leave the CNS fast
**limits the duration of action of the drug
Term
types of benzo's
Definition
-Diazepam (valium)
-Lorazepam (Ativan)

-Temazepam
-Triazolam
-Midazolam
Term
lipophilicity of diazepam
Definition
-highly lipophilic
-goes right into the brain, but then REDISTRIBUTION
-leaves CNS fast too
-stays around in the body for a while bc it's metabolized into a long acting metabolite that gets stored in fat
Term
redistribution
Definition
-drug that enters the brain quickly and LEAVES CNS quickly
*limits the duration of action of the drug
*lipophilic drugs
Term
metabolism of benzodiazepines
Definition
Diazepam-->Long lasting active metabolite via P450 in the liver-->conjugation and excretion

Lorazepam-->just right to excretion; no P450
Term
diazepam pharmacokinetics
Definition
-short half life: .5-2 hours
-long elimination half life: 30-60 hours
-very lipid soluble
Term
lorazepam pharmacokinetics
Definition
-half life of 1-6 hours
-elimination half life 10-18 hours
-more water soluble, enters brain slowly

used a lot for anxiety
Term
half-life advantages to benzodiazepines
Definition
-therapeutic uses depend on half life

LONG half life: anticonvulsants (clonazepam)
SHORT ELIMINATION half life: hypnotics, sleep aids (temazepam)
LONG half life: anti-anxiety (Lorazepam)
Term
BZD drug interactions
Definition
-on the whole, BDZs are safe, but they are CNS depressants
-potentiate effects when in combo with other CNS depressants (ex: alcohol)
-inhibitors or activators of CYP3A4
Term
side effects of BZDs
Definition
-lightheadedness, increased reaction time
*hangover effect with long elimination preparations - drowsiness, confusion
-rebound withdrawal effects: rebound anxiety or wakefulness, especially with drugs with short half life or with abrupt discontinuation of the drug (usually the opposite effect of what the drug is intended for)
Term
side effects of high doses of BDZs
Definition
-toxic effects at higher doses

-ataxia ("drunken sailor walk"-GABA effect in cerebellum) and nystagmus
-anterograde amnesia
-paradoxical excitement

Dose-dependent
Term
contraindications to BDZ use
Definition
-COPD, OSA; BDZ may decrease muscular tone in upper airway
-alcoholics and older patients with liver problems need BDZ that aren't metabolized by a P450
Term
tolerance, abuse, dependence of BDZ
Definition
-some risk of dependence and abuse but much less than with barbiturates
-abuse more prevalent in patients who also abuse other substances
-may be physical dependence after long-term use
Term
therapeutic uses of BDZs
Definition
MANY!

-anxiety
-sleep disorders
-seizures
-skeletal muscle spasms
-alcohol withdrawal
-preanesthetic medication
Term
Flumazenil
Definition
-BDZ receptor ANTAGONIST
-reverses the effects of BDZs
-hastening recovery from BDZ sedation or anesthesia
-only administered IV, in hospital setting
Term
GABA-A receptor subtypes
Definition
alpha 1 - sedation (cerebral cortex)

alpha 2 - anxiolytic (limbic region, striatum, cortex)
Term
Z-drugs: effects/uses, pharmacokinetics
Definition
ex: Zolpidem (Ambien)

-NON-BDZ that acts at the BDZ receptor (not a 7-membered ring)
-shortens sleep latency, prolongs sleep time
-does NOT treat anxiety
-plasma t1/2=1-3 hours
-can result in wakeful behavior and amnesia at increased doses
Term
safety and AE of Z-drugs
Definition
(Zolpidem)

-risk of abuse and tolerance low when used as directed
-few withdrawal reactions (though have been reported)
-no tolerance to therapeutic effects
Term
Buspirone
Definition
-used to treat generalized anxiety with limited severity
-partial agonist at serotonin receptors
**lacks CHS depressant properties**
-slow onset of action
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