Drug of abuse mechanisms

Question 1

Alcohol

Answer 1

• decreases NMDA sensitivity
• increases GABA sensitivtity
• down regulates calcium channels
• up-regulates nicotine receptor gated sodium channels

Question 2

Amphetamine

Answer 2

-acts via releasing stored monoamines especially noradrenaline and dopamine

Question 3

Buprenorphine

Answer 3

partial opioid agonist
lower doses= mild agonism
higher doses- antagonistic effects

Question 4

Cannabis

Answer 4

• acts via cannaboid receptors

- CB1 is central- inhibits GABA tone in the substantia nigra

Question 5

Clonidine

Answer 5

• presynaptic alpha 2 agonist

- reduces normal sympathetic tone

Question 6

Dexfenfluramine

Answer 6

-produces massive serotonin release from nerve endings

Question 7

Disulfriam

Answer 7

• inhibits aldehyde dehydrogenase

- leads to accumulation of acetaldehyde if ETOH is consumed- produces unpleasant reactions

Question 8

Levomethdyl acetate (LAAM)

Answer 8

• long-acting opioid agonist
• similar to use as methadone
• not used due to prolonged QT

Question 9

LSD

Answer 9

-5-HT2A partial agonism

Question 10

MDMA

Answer 10

2 isomers -R and S
-R produce LSD-like effects
S-amphetamine like properties
-LSD- action is mediated via serotonin release from presynaptic neurons
-in long term this can damage serotonergic tracts irreversibly

Question 11

Methadone

Answer 11

• opioid receptor agonist
• longer acting than heroin and orally available
• pure mu agonist

Question 12

Naloxone

Answer 12

-shorter acting opioid mu antagonist

Question 13

Naltrexone

Answer 13

-longer acting opioid mu antagonist

Question 14

Phencyclidine

Answer 14

• non-competitive NMDA antagonist similar to ketamine

- also binds to sigma receptors

Question 15

Varenicline

Answer 15

• Champix
• partial agonist at the alpha4beta2 unit of nicotininc acetylcholine receptor
• relieves withdrawal symptoms and reduces the rewarding properties of nicotine

Question 16

Sildenafil

Answer 16

-phosphodiesterase-5 inhibitor