Anxiolytic-sedative-hypnotic Drugs Flashcards
What does sedation mean?
Decreases activity, calm, although awake
What does anxiolytic mean?
Px is relaxed, unconcerned with surroundings and is fully functional
What does hypnosis mean?
Drowsiness and leads to sleep (noise hey wake up)
What does anesthesia mean?
Not wake up if noise
What factors determine the duration of action and clinical utility of barbiturates?
Linear slope of dose and effects
What is the action of barbiturates on electrically excitable tissue?
- Extends duration of GABA channel opening
- At high levels may open the channel
- reversible depression on all excitatory tissue
What is meant by pharmacokinetic/metabolic tolerance?
Increased rate of drug metabolism
What is meant by pharmacodynamic tolerance?
Changes in responsiveness of the CNS
What is the mechanism of barbiturates?
- increases the duration of the opening of GABA channels
- termination of action is by redistribution of ultra fast acting drugs (thiopental) outside the CNS
What is the mechanism of benzodiazepines?
- ups the frequency of the opening of GABA a receptor chloride channel
What is changing the urinary pH useful in treating an overdose of phenobarbital?
- phenobarbital is a weak acid
- weak acids are re absorbed at a low pH
- increasing the pH can lead to increased drug excretion
- treat and overdose with sodium bicarbonate
- only works with phenobarbital
- DNW with high lipid soluble barbs
What are possible benefits of non-benzodiazepine benzodiazepine receptor agonists?
A
What do sedative-hypnotic drugs do at low and high doses?
Low: relief anxiety and cause sedation (a few don’t)
High: encourage sleep, general anesthetics, death
What do the benzos and barbs follow for there dose-effect curve?
Barbs - linear, easy to overdose
Benzos - non linear, harder to overdose
What is Valium?
Diazepam
What do barbiturates end with?
-tal
Why are there secondary effects of barbiturates (anesthesia and bad effects)?
- Antagonist of the AMPA glutamate receptor
- non synaptic membrane effects other than glu and GABA
- this is the reason it is a good CNS depressant
How are barbiturates excreted?
- metabolized and excreted
- liver
- exceptions: phenobarbital is excreted as is and around 4-5 day. Thiobarbiturates is the only fast excreted one
What do barbs do for metabloism of other drugs?
- effect cyt P450
- effect metabolism of other Drugs and itself
What is unique about phenobarbital in relation to tolerance?
Both pharmacodynamic and pharmacokinetic tolerance
What do the barbs and benzos do to sleep?
- stage 2 sleep is increased (rapid onset)
- REM sleep duration is decreased
- stage 4 - slow wave sleep is decreased
What is the main reason barbs are a anesthetic?
High lipid solubility
Other as mentioned
What is metharbital?
Prodrug form of phenobarbital
What other random thing is phenobarbital used to treat?
Tonic-clonic seizures
