CNS Depressants

Question 1

Diazepam (Valium)

Answer 1

Long-Acting Benzodiazepine
Binds to and attenuates GABA receptors
Half-life of 30 hours, to desmethyldiazepam (half-life of 50 hours), to oxazepam (half-life of 7 hours)
Useful for chronic anxiety, or sleep deprivation associated with anxiety

Question 2

Triazolam (Halcion)

Answer 2

Short-Acting Benzodiazepine
Binds to and attenuates GABA receptors
Half-life of 3 hours, to a-hydroxytriazolam (half-life of 1-2 hours)
Effective in acute anxiety and more often clinically for surgery

Question 3

Zolpidem (Ambien)

Answer 3

Non-benzodiazepine benzodiazepine receptor agonist (NBRA)
Relatively selective for type 1 benzodiazepine receptors
Rapidly absorbed with half-life of 2.6 hours. This means no hangover
Stage 3 sleep usually preserved, REM sleep usually unaffected

Question 4

Eszopiclone (Lunesta)

Answer 4

Non-benzodiazepine benzodiazepine receptor agonist (NBRA)
First sedative-hypnotic indicated for insomnia
Rapid onset and 6 hour half-life
Binds to all 3 benzodiazepine receptors
Mechanism for selectivity unclear

Question 5

Ethanol

Answer 5

Drinking Alcohol
Dose-related progression of CNS depression
Polysynaptic reticular activating system most susceptible and cerebral cortex
Blood ethanol 40-150mg% causes euphoria, disorganized though, and dulled performance
180-400mg% depression of cerebellum, loss of motor control
350-600mg% depression of midbrain, spinal reflexes, depression of medullary respiratory control.
Reduces membrane viscocity
Increased GABA-A activity
Decreased NMDA glutamate activity
Increase 5HT
Alcohol Dehydrogenase uses NAD+
Microsomal ethanol oxidizing system uses NADPH to metabolize
Metabolizes to acetaldehyde, which metabolizes to acetate

Question 6

Methanol

Answer 6

Metabolized into Toxins
Metabolized to formaldehyde by alcohol dehydrogenase
Formaldehyde metabolized to formic acid by aldehyde dehydrogenase
Both are highly toxic
Metabolic acidosis, blindness, seizures, coma, death
Treat with ethanol (because of zero-order elmination, ethanol competes for metabolism by alcohol dehydrogenase, slowing creation of formaldehyde)
Treat with fomepizole

Question 7

Flumazenil (Romazicon)

Answer 7

Anti-benzodiazepine
Competitively binds to benzodiazepine sites and blocks action
Treatment of benzo or NBRA overdose
Hasten recovery from benzo sedation

Question 8

Disulfiram (Antabuse)

Answer 8

Inhibits aldehyde dehydrogenase

Build-up of acid aldehyde causes you to feel sick and horrible

Question 9

Acamprosate (Campral)

Answer 9

Reduces glutamate neurotransmission
Upregulation of glutamate receptors due to chronic alcohol use creates excitatory withdrawal effects.
Reducing transmission treats withdrawal

Question 10

Baclofen

Answer 10

GABA-B receptor agonist
Treats withdrawal
Stimulation of GABA-B produces the inhibitory effect, but on different receptors
Reduces alcohol-related anxiety and craving

Question 11

Naltrexone

Answer 11

Decreases the rewarding effects of alcohol

Question 12

Fomepizole (Antizol)

Answer 12

Inhibits alcohol dehydrogenase
This prevents methanol from being converted into formaldehyde
For treatment of methanol poisoning.

Question 13

Benzodiazepine Sleep

Answer 13

Decrease Latency to Onset of sleep
Decrease Number of awakenings
Increase sleep time
Decrease stage 0 (wakefulness)
Increase stage 2 (non-REM)
Decrease slow wave sleep (Stage 3 and 4)
Shorten REM cycle, but increase the number of REM cycles

Question 14

Non-benzodiazepine benzodiazepine receptor agonist (NBRA)

Answer 14

Short-acting hypnotic agents
Rapidly absorbed, no active metabolites
Little anti-anxiety, muscle relaxant or anti-convulsant at hypnotic doses
Bind to Benzodiazepine receptor and facilitate GABA