Neuro 2 Flashcards
Barbituates:
Name (4)
- phenobarbital
- pentobarbital
- thiopental (only one commonly used now)
- secobarbital
Barbituates:
MOA
Clinical Use (2)
“BarbiDURATes INCREASE DURATION”
-Facilitate GABA-A action by INCREASE DURATION of Cl- channel opening–>decrease neuron firing
- Sedative for anxiety/seizures/insomnia
- induction of anesthesia (THIOPENTAL)
“Barbie likes it to last longer, while Ben likes it more frequently” (yes, barbie dumped ken for ben)
Barbituates:
Adverse(4)
Contra(1)
Overdose treatment
- Respiratory & Cardiovascular depression (can be fatal)
- CNS depression (exacerbated by ETOH)
- Dependence
- P450 inducer
- Contra: Porphyrias
- Overdose tx: supportive (assist resp. and maintain BP)
Benzodiazepines:
Name 8
- Diazepam
- Lorazepam
- Triazolam
- Temazepam
- Oxazepam
- Midazolam
- Chlordiazepoxide
- Alprazolam
Benzodiazepines:
MOA
Which have short half-lives? Why does this matter?
“FREnzodiazepines INCREASE FREQUENCY”
-Facilitate GABA-A action by INCREASE FREQUENCY of Cl- channel opening
- Most drugs have long half-lives and active metabolites except ‘ATOM’
1. Alprazolam
2. Triazolam
3. Oxazepam
4. Midazolam - these are short acting–>higher addiction potential
What 3 drugs all bind the GABA-A Receptor?
What type of receptor is it?
- Benzo
- Barbs
- Alcohol
- Ligand-gated Cl- channel
Benzodiazepines: Clinical uses (8)
- Anxiety
- spasticity
- Status epilepticus (lorazepam/diazepam/midazolam)
- eclampsia
- detox (esp ETOH-withdrawal)
- Night terrors/ sleep walking (increase STAGE2/ decrease STAGE4&REM)
- General anesthetic (amnesia, muscle relaxation)
- hypnotic (insomnia)
What 3 benzo’s are used to treat status epileptics
- Diazepam
- lorazepam
- midazolam
Benzodiazepines:
Adverse
Comparison to Barbituates
Overdose treatment
- dependence
- CNS depression (exacerbated by ETOH)
- precipitate seizures w/ causing Acute Benzo if chronic Benzo use
- Benzos safer than Barbs b/c less respiratory depression, coma, antidote available
- Overdose tx: Flumazenil (competitive GABA:Benzo-R antagonist
Non-benzodiazepine Hypnotics:
Name 3
“all ZZZs put you to sleep”
- Zolipidem
- Zaleplon
- esZopiclone
Non-benzodiazepine Hypnotics: MOA Effect on sleep cycle Clinical Use (1) Duration?
- Bind BZI subtype of GABA-R
- Sleep cycle less affected (no change in REM) as compared with Benzos
- insomnia
- short duration b/c rapidly metabolized by liver
Non-benzodiazepine Hypnotics:
Adverse (2)
Antidote
- Ataxia
- HA/ confusion
-effects reversed by Flumazenil
Non-benzodiazepine Hypnotics:
Compare to older sedative hypnotics(4)
- Modest day-after psychomotor depression
- few amnestic effects
- less dependence risk than Benzos
- lower abuse potential (increase dose= increase GI upset)
2 ways for local anesthetic to cross BBB?
- lipid soluble
2. active transport
Drugs with decreased solubility in blood have what kind of onset/duration?
Example?
rapid induction & rapid recovery times
- Nitrous Oxide (N2O) has low blood/low lipid solubility
- -> fast induction & low potency
Describe MAC
Minimal Alveolar Concentration
=concentration required to prevent 50% of subjects from moving in response to noxious stimulus
what’s the relationship btw potency and MAC
inverse
potency= 1/MAC
What effect does increased drug solubility in lipids have on potency?
Example?
increase lipid solubility = increase potency
- Halothane has high lipid/blood solubility–> slow induction and high potency
Inhaled anesthetics:
7
all end in “-ane” except N2O
- Desflurane
- Halothane
- Enflurane
- Isoflurane
- Sevoflrane
- Methoxyflurane
- N2O
What kind of effect does N2O as a inhaled anesthetic?
Not strong enough to suppress CNS alone but potentiates other drugs when used in combo
Inhaled anesthetics:
MOA
Effects (4)
- Unknown MOA
- Myocardial depression
- respiratory depression
- increased cerebral blood flow (decrease cerebral metabolic demand)
- N/V (couple with anti-emetic post-surgery)
Inhaled anesthetics: Adverse 1. Halothane 2. Methoxyflurane 3. Enflurane 4. N2O
- ‘H’alothane–> ‘H’epatotox
- Methoxyflurane –>Nephrotox
- ‘E’nfluane–> ‘E’pileptic potential
- N2O–>expansion of trapped gases in body cavity
Describe Malignant Hyperthermia
Etiology
-rare, life-threatening condition in which inhaled anesthetics or succinylcholine induce F/Severe Muscle contractions
- Autosomal Dominant with variable penetrance
- Mutation in VSens RyR–>increase Ca+2 release from SR
Treatment for Malignant Hyperthermia
MOA
Dantrolene, RyR antagonist
IV anesthetics:
Name 5
“The Mighty King Proposes Foolishly to Oprah”
- Thiopental (Barb)
- Midazolam (Benzo)
- Ketamine (Arylcyclohexylamines)
- Propofol
- Opioid (morphine/ fentanyl)
Thiopental: Potency Lipid Solubility Brain entry/ brain effect Use
- high potency
- high lipid solubility
- rapid entry into brain/ decrease cerebral blood flow
Use: induction of anesthesia and Short surgical procedures
Thiopental:
elimination
rapid redistribution into tissue and fat
Midazolam: Use Admin w/... Adverse (3) Treatment of overdose
- endoscopy (short procedure where you don’t need to put patient completely under
Admin with Gaseous Anesthetics and Narcotics
Adverse:
- severe post-op Respiratory depression
- decrease BP
- anterograde amnesia
Overdose tx: Flumazenil
Ketamine ( a Arylcyclohexylamines)
MOA
Heart effects, CNS effects
Adverse (2)
PCP analog–>block NMDA-R
- cardiovascular stimulants/ increase cerebral blood flow
- disorientation
- hallucination/ bad dreams
Propofol: MOA induction Use(2) comparison to thiopental
- potentiates GABA-A and inhib NMDA-R (‘pro’ GABA-a, ‘fool’ NMDA-R)
- rapid induction
- Sedation in ICU
- short procedures
Less post-op Nausea than thiopental
Opioids:
Name 2 IV
MOA
- Morphine
- Fentanyl
-bind mu-R and typically combined with other CNS depressants during general anesthesia