LCDC Pharmacology of Addictions 1 — Questions and Answers
Question 1: Which neurotransmitter is primarily responsible for the reinforcing effects of most addictive substances in the brain's reward pathway?
- Serotonin
- Dopamine (Correct answer)
- GABA
- Norepinephrine
Correct answer: Dopamine
Dopamine release in the mesolimbic pathway (nucleus accumbens) is the primary mechanism underlying the reinforcing and rewarding effects of addictive drugs.
Question 2: What is the primary mechanism of action of methadone in treating opioid use disorder?
- Partial agonist at mu-opioid receptors
- Full agonist at mu-opioid receptors with long half-life (Correct answer)
- Antagonist at all opioid receptors
- Blocks dopamine reuptake
Correct answer: Full agonist at mu-opioid receptors with long half-life
Methadone is a full mu-opioid receptor agonist with a long half-life (24–36 hours), which prevents withdrawal and reduces cravings without producing the rapid euphoric peaks of shorter-acting opioids.
Question 3: Which medication causes an unpleasant reaction when alcohol is consumed and is used as a deterrent in treating alcohol use disorder?
- Naltrexone
- Acamprosate
- Disulfiram (Correct answer)
- Bupropion
Correct answer: Disulfiram
Disulfiram inhibits aldehyde dehydrogenase, causing acetaldehyde accumulation when alcohol is consumed, resulting in flushing, nausea, and palpitations.
Question 4: A drug's 'half-life' is best defined as:
- The time required for a drug to reach peak concentration
- The time it takes for the body to eliminate half of the drug's concentration (Correct answer)
- The duration of a drug's therapeutic effect
- The time between first dose and onset of tolerance
Correct answer: The time it takes for the body to eliminate half of the drug's concentration
Half-life is the time required for the plasma concentration of a drug to decrease by 50%, which determines dosing frequency and how long the drug remains active in the body.
Question 5: Which class of drugs produces CNS depressant effects primarily by enhancing the activity of GABA receptors?
- Opioids
- Stimulants
- Benzodiazepines (Correct answer)
- Hallucinogens
Correct answer: Benzodiazepines
Benzodiazepines bind to GABA-A receptors and enhance the inhibitory effect of GABA, producing sedation, anxiolysis, and anticonvulsant effects.
Question 6: Cocaine primarily produces euphoric effects by:
- Stimulating dopamine receptors directly
- Blocking the reuptake of dopamine, serotonin, and norepinephrine (Correct answer)
- Increasing release of endogenous opioids
- Enhancing GABA inhibition in the prefrontal cortex
Correct answer: Blocking the reuptake of dopamine, serotonin, and norepinephrine
Cocaine blocks monoamine reuptake transporters, increasing synaptic levels of dopamine, serotonin, and norepinephrine, with dopamine accumulation in the nucleus accumbens being most responsible for euphoria.
Question 7: Which FDA-approved medication blocks opioid receptors and is indicated for treating both opioid use disorder and alcohol use disorder?
- Buprenorphine
- Disulfiram
- Naltrexone (Correct answer)
- Acamprosate
Correct answer: Naltrexone
Naltrexone is a full opioid antagonist that blocks the reinforcing effects of both opioids and alcohol, and is approved for treating both substance use disorders.
LCDC Pharmacology of Addictions 1
Which neurotransmitter is primarily responsible for the reinforcing effects of most addictive substances in the brain's reward pathway?