Sedative Hypnotics Flashcards
What is the general MOA for barbiturates, benzodiazepines, ethanol, and non-benzo “z” drugs?
They potentiate GABA (inhibitory transmitter) → CNS depression.
The degree of sedation-hypnosis depends on ____?
The dose. Sedation → Hypnosis → Anesthesia → Coma.
Name the barbiturates.
“-barbital”
- Pentobarbital (Short acting)
- Secobarbital (Short acting)
- Phenobarbital (Long acting)
- Amobarbital
- Thiopental
Thiopental is…
Lipid soluble. Redistributed from brain to muscle and fat tissue: quick onset and rapid offset.
Use of barbiturates?
- Anxiety and insomnia
- Seizures (Phenobarbital)
- Induction of anesthesia (Thiopental)
MOA of barbiturates?
“barbiDURATES”
Increases the duration of Cl- channel openings → hyperpolarization → potentiates GABA → inhibitory effect.
“No ceiling effect” aka GABA does NOT have to be present for the Cl- channel to open.
Induces full respiratory arrest.
No antidote for barbiturates. Need to alkalinize urine for ion trapping and provide supportive care.
Overdosing is more dangerous than overdosing on benzos.
Name the benzodiazepines.
“-pam / -lam”
- Chlordiazepoxide (Long acting)
- Diazepam (Long acting)
- Alprazolam (Short acting)
- Lorazepam
- Clonazepa,
- Midazolam
- Estazolam
- Flurazepam
~ Long acting drugs not good for elderly patients ~
Uses of the specific benzos.
- Alprazolam - Panic disorder
- Lorazepam, clonazepam, diazepam - Status epilepticus
- Midazolam - anesthesia (not have recollection of events)
- Estazolam, Flurazepam - Insomnia
Safe benzodiazepines that are used in elderly patients?
- Oxazepam
- Temazepam
- Lorazepam
Benzodiazepines get metabolized in the liver (converted to active metabolites). Elderly patients most likely have decreased liver functions. So, the drugs above bypass phase I metabolism and are only conjugated.
MOA of benzodiazepines?
“FRENZOdiazepines”
Increases the frequency of Cl- channel opening.
“Ceiling effect” b/c needs GABA to work.
Overdose will not cause respiratory depression, unless combined with other CNS depressants.
Use of benzodiazepines?
- Anxiety
- Sedative - hypnotic
- Insomnia (anterograde amnesia)
- Muscle relaxant
- Anticonvulsant
Toxicities of benzos?
- Drowsiness, hangover
- Mild euphoria (abuse potential)
- Anterograde amnesia (date-rape drugs)
- Physical dependence
- Tolerance
- Fetal malformations → floppy baby syndrome. Don’t give to pregnant women.
Withdrawal of benzos?
- Rebound anxiety
- Seizures
~ Need to taper doses.
What is the antagonist/antidote of benzos?
Flumazenil
~ Barbiturates do not have antagonists. So, need to alkalinize urine.
What does flumazenil do?
Reverses benzodiazepine toxicity in overdose. When benzo is used for anesthesia, this drug will rapidly result in patient recovery.
