L13- Drugs of Abuse

Question 1

______ part of the brain is generally responsible for addiction

Answer 1

mesolimbic dopamine system

Question 2

list the CNS depressants

Answer 2

ethanol
benzodiazepines
barbiturates

Question 3

compare the effects of ethanol at low and high doses

Answer 3

Low: perceived as stimulation due to suppression of inhibitory system
-motor incoordination, and or sleepiness in some people

High- at enough levels drowsiness and eventually coma and death

Question 4

what cellular functions does ethanol have

Answer 4

GABA(a) receptors
Kir3/GIRK channels
adenosine reuptake
glycine receptor
NMDA receptors
5-HT3 receptors

Question 5

give the timeline of ethanol withdrawal events

Answer 5

6-12h: tremor, n/v, sweating, agitation, anxiety –> may be followed by hallucinations (visual, tactile, auditory)

24-48h: generalized seizures

48-72h: delirium tremens (5-15% mortality)

Question 6

treatment of alcohol withdrawal

Answer 6

1st choice: long half-life benzodiazepines- diazepam, chlordiazepoxide

2nd choice: intermediate half-life benzos- lorazepam, oxazepam
-for the elderly and Pts with liver failure

Question 7

list the drugs used to treat alcohol addiction (hint- life’s blueprint)

Answer 7

Disulfiram: aldehyde dehydrogenase inhibitor –> aversion to drinking (mimics hangovers)

Naltrexone: opioid antagonist –> reduce cravings

Acamprosate: NMDA antagonist –> prevents relapse

[Not FDA approved: Topiramate- enhances GABA function, antagonizes glutamate –> reduce cravings]

Question 8

benzodiazepine and barbiturates withdrawal Sxs

Answer 8

(Note- addiction is rare, physical dependence is not)
tremors, seizures
anxiety, dysphoria
perceptual disturbances, psychosis

Question 9

benzodiazepine and barbiturates withdrawal management

Answer 9

long-acting benzodiazepine (switched from short-acting agent)- diazepam –> gradually reduce dose

Question 10

list the psychostimulants

Answer 10

• methylxanthines: caffeine, theophylline, theobromine
• cocaine
• amphetamines

Question 11

methylxanthines MOA

Answer 11

-blocks presynaptic adenosine receptors, which normally inhibits NE release
=> inc NE release

Question 12

describe the effects of caffeine at different doses

Answer 12

Low, 100-200g (1-2 cups coffee): dec in fatigue, inc mental alertness

Medium, 1.5g: anxiety, tremor

High, 2-5g: spinal cord stimulation

Question 13

methylxanthines withdrawal symptoms

Answer 13

fatigue

sedation

Question 14

______ can be used to treat cocaine addiction

Answer 14

antidepressants- SSRIs

dopamine agonists

Question 15

______ can be used to treat nicotine addiction

Answer 15

• nicotine replacement therapy
• bupropion
• varenicline: partial agonist of nicotinic receptors –> reduces reward of smoking

Question 16

• (1) opioids
• (2) overdose Tx
• (3) opioid Tx for withdrawal

Answer 16

1- heroin, morphine, codeine, oxycodone
2- naloxone (opioid antagonist)
3- methadone, buprenorphine (naltrexone is addiction, not withdrawal Tx)

Question 17

Marijuana:

• (1) most effective component
• cannabinoids will activate (2) and (3) receptors (include receptor types, location)

Answer 17

1- Δ9-tetrahydrocannabinol / dronabinol
2- CB1, Gi, brain –> mediates the effects of THC
3- CB2, Gi, immune cells

Question 18

list the psychedelic agents

Answer 18

• LSD, mescaline, psilocybin
• Phenciclidine (PCP)
• MDMA

Question 19

LSD works on (1) receptors to induce (2) effects

Answer 19

1- 5-HT2 receptors

2- mydriasis, HTN, tachycardia, inc body T, flushing, sweating, tremors, piloerection