Pharmacology of Substances Flashcards

When comparing methadone and buprenorphine for opioid use disorder treatment, which statement about overdose risk is MOST accurate?

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.

A client describes using LSD and experiencing 'flashbacks' weeks later without taking the drug again. This phenomenon is clinically known as:

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.

Nicotine's primary mechanism of physical dependence involves:

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.

Varenicline (Chantix) reduces nicotine cravings and withdrawal by acting as a:

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.

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:

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.

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?

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.

The Opioid Risk Tool (ORT) and similar screening instruments are used prior to prescribing opioids primarily to assess:

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.