Chapter 8 - Depressants

Question 1

What is a depressant?

Answer 1

drug that diminishes physiological activity

Question 2

Therapeutic uses of depressants

Answer 2

anxiety, sleep management, seizures, anesthesia
-most produce positive subjective effects (activate reward pathways); high abuse liability

Question 3

What are some common depressants?

Answer 3

alcohol, barbiturates, benzodiazepines, opioids

Question 4

Most depressants act through increased activity of ____

Answer 4

GABA

Question 5

Depressants and GABAA receptor

Answer 5

Ionotropic receptor that allows entry of Cl- ions; hyperpolarizes neurons which decreases their firing rate; five subunits; two binding sites for GABA

Question 6

There are ____ sites on the GABAA receptor that enhance GABA transmission

Answer 6

allosteric

Question 7

What are barbiturates?

Answer 7

became available after development of barbital from barbituric acid; became widely used for insomnia, nervousness, sedation, anesthesia; first effective anti-seizure medication

Question 8

Barbiturates are ____ depressants and are sometimes referred to as ____

Answer 8

CNS; sedatives

Question 9

barbiturates are classified by their…

Answer 9

speed of onset and duration of action

Question 10

speeds and durations of barbiturates

Answer 10

ultra-shortacting: effects in 20-30s, lasts ~30min ex. thiopental
short-acting/intermediate: ex. pentobarbital
long-acting: effects in ~1hr, last ~12hr ex. phenobarbital

Question 11

Barbiturate as a drug of abuse

Answer 11

positive reinforcing effects; reduce feelings of stress and anxiety; produce feelings of well-being and lower inhibitions

Question 12

depressants enhance GABA inhibition at sites of action such as…

Answer 12

cerebral cortex, amygdala, thalamus, and medulla
HOWEVER as doses increase the effects reach deeper into brain cortex>amygdala>medulla
cortex: disinhibition
amygdala: red. anxiety
medulla: resp. depression

Question 13

Inhibition of ____ accounts for
the effects on seizures, memory, attention, and other cognitive functions

Answer 13

cortical activity

Question 14

the ____ effects of barbiturates are due to the inhibition of the amygdala

Answer 14

anti anxiety

Question 15

The effects on ____ result from inhibition of the medulla

Answer 15

respiratory function

Question 16

overdose potential of barbiturates

Answer 16

main concern is respiratory depression; memory blocking effects (forgetting if they took a dose); long term use can lead to shrinking therapeutic index

Question 17

chronic use of barbiturates causes tolerance to the ____ but not to the ____

Answer 17

therapeutic effects: respiratory depressant effects

Question 18

withdrawling from barbiturates

Answer 18

Withdrawal should be done gradually; abrupt withdrawal causes a Barbiturate Abstinence Syndrome (anxiety, muscle weakness, abdominal pain seizures)
-think of it like the opposite of what theyre used for

Question 19

What are benzodiazepines?

Answer 19

produces less drowsiness and cognitive inhibition than barbiturates; relatively common for anxiety disorders

Question 20

short-acting benzodiazepines are used as..

Answer 20

“as needed” acute anxiety situations

Question 21

intermediate/long-lasting benzodiazepines are used as…

Answer 21

relief for or to prevent generalized anxiety disorder

Question 22

Long-lasting benzodiazepines produce ____

Answer 22

active metabolites

Question 23

Benzodiazepines abuse

Answer 23

High abuse potential; positive subject effects but less than barbiturates

Question 24

Benzodiazepine withdrawal syndrome

Answer 24

Characterized by depression, anxiety, mania; can last several months; avoiding withdrawal could be main reason to continue use

Question 25

Risks of using benzodiazepines

Answer 25

Accidental injury; poor decision making; most misuse is from combining with alcohol;

Question 26

Benzodiazepines serve as positive modulators by ____

Answer 26

binding to an allosteric site known as the benzodiazepine site (separate from barbiturate site)

Question 27

What are the two types of benzodiazepine sites?

Answer 27

BZI site: high affinity BZII site: low affinity

Question 28

What are Z-drugs?

Answer 28

non-benzodiazepine hypnotics (sleep aids); generic names typically start w Z; high binding affinity for GABAA receptors

Question 29

Risks of Z-drugs

Answer 29

Sleep-related complex behaviours (walking, driving, cooking, eating, conversing while asleep); recommends 8hrs of sleep for effects to wear off

Question 30

What is Gamma-Hydroxybutyrate (GHB)?

Answer 30

a drug (white, tasteless, dissolves in water) and a NT; used instrumentally (narcolepsy, schedule II) and recreationally (abused, schedule I); associated with sexual assault

Question 31

What two precursor drugs is GHB easily produced from?

Answer 31

GBL (gamma-butyrolactone, immediate precursor of GHB); 1,4 butanediol (readily converted to GHB); biotransformation occurs in “alcohol” metabolic pathway in liver

Question 32

GHB is also produced naturally in the brain from ____

Answer 32

GABA -GHB is stored and released with GABA; GABA is the product of GHB metabolism

Question 33

How many GHB receptors are there?

Answer 33

one, with evidence of another -G-protein-coupled receptor -inhibitory effects on hippocampus, cerebral cortex, & basal ganglia

Question 34

Pharmacokinetics of GHB

Answer 34

concentrated within 45 mins, onset of effects after about 15-20; metabolized into GABA in liver and brain; about 30min half life

Question 35

Pharmacological effects of GHB

Answer 35

longer time in deep sleep; subjective effects are time dependent (similar to alcohol; good at first but later effects mood, memory, drowsiness, etc)

Question 36

Overdosing on GHB

Answer 36

nausea; decreased BP; decreased HR; unconsciousness -most emergency room visits related to GHB involve polydrug use, often alcohol

Question 37

What are inhalants?

Answer 37

vaporous chemicals with psychoactive effects

Question 38

What are some compounds of inhalants?

Answer 38

amyl nitrate ("poppers," warmth, enhances sexual experiences); nitrous oxide (laughing gas, aerosol spray cans, euphorogenic but can also be a depressant); volatile solvents (hydrocarbon chemicals, toluene, gasoline, acetone)

Question 39

Who uses inhalants?

Answer 39

mainly adolescents; mainly bc none of the compounds are legal (easily accessible) and wear off quickly

Question 40

Ways to administer inhalants

Answer 40

sniffing (direct inhalation); huffing (soaking a cloth); bagging (inhaling from a bag)

Question 41

Pharmacological actions of inhalants

Answer 41

most are depressants (share some mechanisms of actions with alcohol); After several days of use there is an upregulation of NMDA receptors to compensate for this antagonism (tolerance to subjective effects); positive modulation of GABAA receptors

Question 42

4 stages of inhalant effects

Answer 42

1. stimulant like positive subj effects 2. behaviours resembling alcohol intoxication 3. enhanced depressant effects 4. overdose (unconsciousness, seizures, cardiac arrest)

Question 43

How is inhalant overdose dangerous?

Answer 43

cardiac arrest is the primary cause of sudden sniffing death syndrome due to poor oxygen availability (occurs when vapors complete with oxygen inhalation and absorption) -Chronic use of inhalants can lead to loss of brain tissue: ventricular enlargement and white matter degeneration