Section 4: CNS

Question 1

BZ mech

Answer 1

Act through BZ receptors, an allosteric site in the GABA-A complex in the CNS.
Increase FREQUENCY of Cl- channel opening (FREnzodiazepines vs barbiDURates), cause membrane hyperpolarization.
BZ1 receptor mediates sedation, BZ2 mediates anti-anxiety & cognitive impairment.

Question 2

Aprazolam

Answer 2

Class: BZ
Use: Anxiety, panic, phobias
“-olam” suffix -> short acting

Question 3

Diazepam

Answer 3

Class: BZ
Use: Anxiety, pre-op sedation, muscle relaxation, withdrawal states
Long acting

Question 4

Lorazepam

Answer 4

Class: BZ
Use: Anxiety, pre-op sedation, status epilepticus (IV)

Question 5

Midazolam

Answer 5

Class: BZ
Use: Pre-op sedation, anesthesia (IV)
“-olam” suffix -> short acting

Question 6

Temazepam

Answer 6

Class: BZ
Use: Sleep disorders

Question 7

Oxazepam

Answer 7

Class: BZ
Use: Sleep disorders, anxiety
Short acting.

Question 8

Treatment and symptoms of alcohol withdrawl (with timeline)

Answer 8

Treatment: long-acting BZs (diazepam, chlordiazepoxide)
8-12 hours: tremulousness, insomnia, anxiety, autonomic instability
12-24 hours: seizures
48-96 hours: delerium tremens (fever, disorientation, severe agitation)

Question 9

Name the short acting BZs

Answer 9

“-olam’s” Midazolam, Alprazolam

and Oxazepam

Question 10

Name the long acting BZs, and why they’re long acting

Answer 10

Diazepam, Chlordiazepam

All BZs metabolized by the liver. These

Question 11

BZ side effects, contraindications, and withdrawal sx

Answer 11

Addiction (more connon in short-acting), somnolence, confusion, disorientation, ataxia
Containdications: old age, other CNS depressants (1st gen anti-H, alcohol, barbs, neuroleptics)
Withdrawal: rebound insomnia, anxiety, seizures if used as antiepileptic or in high doses (similar to alcohol withdrawal

Question 12

All BZ uses

Answer 12

Panic disorder (BZs are second line to SSRIs)
GAD (BZs are second line to SNRIs)
Alcohol withdrawl
UMN spasticity
Consious sedation for minor procedures
General anesthesia and anterograde amnesia
Parasomnias in children (sleepwalking, night terrors)
Status epilepticus (BZs are 1st line for acute; phenytoin for prophylaxis)

Question 13

Flumazenil

Answer 13

Competitive antagonist at the BZ receptor, reverses BZ sedation but precipitates S/E like seizures

Question 14

Barbiturate mech

Answer 14

Binds to allosteric site in the GABA-A complex in the CNS.

Increase DURATION of Cl- channel opening (FREnzodiazepines vs barbiDURates), cause membrane hyperpolarization.

Question 15

Barbiturate uses

Answer 15

Essential tremor (1st line, along w/ propranolol), seizures (phenobarbital, IV), induction of anesthesia (thiopental, IV)

Question 16

Barbiturate side effects

Answer 16

Hypotension, cardio/resp. depression, CNS depression (coma, avoid in elderly), addiction
Potent CYP450 induction

Question 17

Thiopental

Answer 17

Short acting barbiturate, used IV for induction of anesthesia

Question 18

Phenobarbital

Answer 18

Barbiturate, used IV for seizures

Question 19

Barbiturate distribution and redistribution

Answer 19

Rapidly accumulate in the brain and rapidly redistribute in the tissues (muscle and fat) leading to quick onset and duration of anesthesia

Question 20

Zolpidem, Zaleplon, esZopiclone class and mech

Answer 20

Class: non-BZ hypnotics
Mech: Binds to the SAME allosteric site in the GABA-A complex as BZs (BZ1 site)
(Alcohol and Barbiturates each have their own site)

Question 21

Zolpidem, Zaleplon, esZopiclone antidote

Answer 21

Flumazenil (same as BZs, can still precipitate seizures)

Question 22

Zolpidem, Zaleplon, esZopiclone use:

Answer 22

Sleep-onset insomnia. Zolpidem and Zaleplon are rapidly metabolized by the liver. Fast onset, short half-life. Eszopiclone has the longest half-life and can be used for sleep maintenance too

Question 23

Zolpidem, Zaleplon, esZopiclone side effects

Answer 23

Less likely to cause tolerance/addiction compared to BZs
Still contraindicated in elderly and with other CNS depressants (1st gen anti-H, EtOH, BZs, barbs), can cause delirium/cognitive impairent

Question 24

Ramelteon

Answer 24

Class: Melatonin agonist
Use: Insomnia
Mech: maintaings circadian rhythm in the SCN of the hypothalamus

Question 25

Fomepizol

Answer 25

Class: Alcohol dehydrogenase inhibitor
Use: ethylene glycol, methanol, ethanol poisoning
Prevents ethylene glycol-> glycolaldehyde-> glycolic acid-> oxalic acid
Prevents methanol-> formaldehyde -> formic acid