LCAS Pharmacology of Addictive Substances 2 — Questions and Answers
Question 1: Benzodiazepines produce their sedative and anxiolytic effects through which primary mechanism?
- Blocking dopamine D2 receptors in the striatum
- Enhancing GABA-A receptor chloride ion channel activity (Correct answer)
- Stimulating norepinephrine release from the locus coeruleus
- Inhibiting serotonin reuptake in the prefrontal cortex
Correct answer: Enhancing GABA-A receptor chloride ion channel activity
Benzodiazepines bind to a modulatory site on GABA-A receptors and increase the frequency of chloride channel opening, potentiating GABA's inhibitory effects throughout the CNS.
Question 2: Which statement accurately describes the pharmacology of THC (tetrahydrocannabinol)?
- THC produces its effects by stimulating opioid receptors
- THC binds to CB1 receptors in the brain and CB2 receptors in peripheral tissues (Correct answer)
- Cannabis has no potential for dependence or withdrawal
- THC primarily blocks dopamine reuptake transporters
Correct answer: THC binds to CB1 receptors in the brain and CB2 receptors in peripheral tissues
THC, the primary psychoactive component of cannabis, exerts its effects by binding to endogenous cannabinoid receptors — CB1 receptors (CNS) and CB2 receptors (peripheral tissues).
Question 3: MDMA (3,4-methylenedioxymethamphetamine) produces its characteristic empathogenic effects primarily through which neurotransmitter?
- Massive release of opioid peptides
- GABA receptor stimulation
- Massive release of serotonin along with dopamine and norepinephrine (Correct answer)
- Cannabinoid receptor agonism
Correct answer: Massive release of serotonin along with dopamine and norepinephrine
MDMA causes massive presynaptic release of serotonin (its primary effect) along with dopamine and norepinephrine, producing the empathogenic, entactogenic, and stimulant effects.
Question 4: Which medication used in opioid use disorder treatment is classified as a partial agonist at the mu-opioid receptor?
- Methadone
- Naloxone
- Buprenorphine (Correct answer)
- Naltrexone
Correct answer: Buprenorphine
Buprenorphine is a partial mu-opioid receptor agonist with a high binding affinity, producing submaximal opioid effects with a ceiling on respiratory depression, making it safer for maintenance therapy.
Question 5: Naloxone reverses opioid overdose through which pharmacological mechanism?
- It enhances GABA activity to counteract opioid-induced CNS depression
- It competitively antagonizes opioid receptors, displacing opioids (Correct answer)
- It directly stimulates the brainstem respiratory center
- It accelerates hepatic opioid metabolism
Correct answer: It competitively antagonizes opioid receptors, displacing opioids
Naloxone is a competitive opioid receptor antagonist with high binding affinity that rapidly displaces opioids from receptors, reversing respiratory depression, sedation, and analgesia.
Question 6: Which substance class poses the greatest risk of life-threatening withdrawal without medical management?
- Opioids used in isolation
- Cannabis
- Alcohol and benzodiazepines (Correct answer)
- Stimulants such as cocaine
Correct answer: Alcohol and benzodiazepines
Alcohol and benzodiazepine withdrawal can cause generalized tonic-clonic seizures and delirium tremens due to CNS hyperexcitability, and can be fatal without appropriate medical intervention.
Question 7: The 'kindling' phenomenon in alcohol use disorder refers to:
- Increased craving triggered by environmental drug-related cues
- Progressive worsening of withdrawal severity with each subsequent detoxification episode (Correct answer)
- Accelerated spread of addiction from alcohol to other substances
- Initial sensitization to the pleasurable effects of alcohol
Correct answer: Progressive worsening of withdrawal severity with each subsequent detoxification episode
Kindling describes the neurological phenomenon whereby repeated alcohol withdrawal episodes become progressively more severe, with increased risk of seizures and delirium with each successive withdrawal.
LCAS Pharmacology of Addictive Substances 2
Benzodiazepines produce their sedative and anxiolytic effects through which primary mechanism?