MAC Pharmacology of Substances 5 — Questions and Answers
Question 1: When comparing methadone and buprenorphine for opioid use disorder treatment, which statement about overdose risk is MOST accurate?
- Buprenorphine carries higher overdose risk due to its higher potency
- Methadone carries higher overdose risk due to its full agonist activity, long half-life, and QTc prolongation (Correct answer)
- Both medications have identical safety profiles in overdose scenarios
- Buprenorphine has no ceiling effect and therefore greater lethality
Correct answer: Methadone carries higher overdose risk due to its full agonist activity, long half-life, and QTc prolongation
Methadone's full agonist activity combined with its variable and long half-life (24–60 hours) and QTc-prolonging effects make it more dangerous in overdose than buprenorphine, which has a ceiling effect on respiratory depression.
Question 2: A client describes using LSD and experiencing 'flashbacks' weeks later without taking the drug again. This phenomenon is clinically known as:
- Post-acute withdrawal syndrome (PAWS)
- Hallucinogen Persisting Perception Disorder (HPPD) (Correct answer)
- Schizophrenia triggered by LSD
- Dissociative amnesia with perceptual disturbance
Correct answer: Hallucinogen Persisting Perception Disorder (HPPD)
HPPD involves spontaneous re-experiencing of perceptual disturbances (visual distortions, geometric hallucinations) weeks to years after hallucinogen use, without taking the substance again.
Question 3: Nicotine's primary mechanism of physical dependence involves:
- Upregulation of nicotinic acetylcholine receptors (nAChRs) in the brain due to chronic stimulation (Correct answer)
- Downregulation of dopamine receptors in the reward circuit
- Inhibition of acetylcholinesterase, increasing synaptic acetylcholine
- Direct activation of GABA-B receptors in the VTA
Correct answer: Upregulation of nicotinic acetylcholine receptors (nAChRs) in the brain due to chronic stimulation
Chronic nicotine exposure causes upregulation (increased density) of nAChRs; when nicotine is absent, these receptors are understimulated, producing withdrawal symptoms.
Question 4: Varenicline (Chantix) reduces nicotine cravings and withdrawal by acting as a:
- Full agonist at all nicotinic receptors
- Partial agonist at alpha-4 beta-2 nicotinic acetylcholine receptors (Correct answer)
- Pure antagonist blocking all nicotine effects
- Dopamine reuptake inhibitor unrelated to nicotinic receptors
Correct answer: Partial agonist at alpha-4 beta-2 nicotinic acetylcholine receptors
Varenicline is a partial agonist at alpha-4 beta-2 nAChRs, providing enough receptor stimulation to reduce cravings while blocking nicotine's ability to produce full reward if the client smokes.
Question 5: A client with opioid use disorder and chronic pain is being considered for buprenorphine. The counselor should understand that buprenorphine's analgesic effectiveness is BEST described as:
- Ineffective for pain because it is only a partial agonist
- Effective for both OUD and pain, though pain dosing is typically more frequent (TID-QID) (Correct answer)
- Only effective for pain when used in the injectable form
- Equivalent to full agonist opioids at any dose without ceiling
Correct answer: Effective for both OUD and pain, though pain dosing is typically more frequent (TID-QID)
Buprenorphine provides effective analgesia but its analgesic duration (6–8 hours) is shorter than its OUD dosing duration (24 hours), so pain management may require more frequent administration.
Question 6: Which substance class is associated with a 'toxic psychosis' that can persist for months and may be difficult to distinguish from a primary psychotic disorder?
- Alcohol
- Methamphetamine (Correct answer)
- Heroin
- Benzodiazepines
Correct answer: Methamphetamine
Methamphetamine-induced psychosis can persist for months after cessation, with paranoia and auditory hallucinations that are clinically indistinguishable from schizophrenia, particularly after heavy long-term use.
Question 7: The Opioid Risk Tool (ORT) and similar screening instruments are used prior to prescribing opioids primarily to assess:
- The appropriate opioid dose based on pain severity
- A patient's risk for developing opioid misuse, aberrant drug-related behaviors, or addiction (Correct answer)
- Whether a patient qualifies for methadone versus buprenorphine treatment
- The likelihood of overdose based on liver function
Correct answer: A patient's risk for developing opioid misuse, aberrant drug-related behaviors, or addiction
The ORT stratifies patients into low, moderate, or high risk for developing opioid misuse or addiction, helping clinicians make informed prescribing and monitoring decisions.
MAC Pharmacology of Substances 5
When comparing methadone and buprenorphine for opioid use disorder treatment, which statement about overdose risk is MOST accurate?