Pharmacology of Substance Abuse Flashcards

Cannabis produces its psychoactive effects primarily by acting on which receptor system?

Answer: Endocannabinoid receptors (CB1 and CB2)

THC (delta-9-tetrahydrocannabinol) acts as a partial agonist at CB1 receptors in the brain and CB2 receptors in peripheral tissues, mimicking endogenous cannabinoids.

A client on methadone maintenance reports that a new medication prescribed by their physician has reduced methadone's effectiveness. Which class of medication most commonly causes this interaction?

Answer: CYP3A4 inducers (e.g., rifampin, carbamazepine)

CYP3A4 enzyme inducers accelerate methadone metabolism, lowering plasma levels and potentially precipitating withdrawal in stable MAT patients.

Which statement about nicotine's pharmacology is accurate?

Answer: Nicotine activates nicotinic acetylcholine receptors and indirectly increases dopamine release

Nicotine binds to nicotinic acetylcholine receptors (nAChRs) in the VTA, stimulating mesolimbic dopamine release and producing reinforcing effects.

MDMA (Ecstasy) is unique among stimulants because it produces empathogenic effects primarily through:

Answer: Causing large-scale serotonin release while also affecting dopamine and norepinephrine

MDMA causes massive serotonin release (along with dopamine and norepinephrine), which produces its characteristic feelings of emotional openness, empathy, and euphoria.

Which pharmacological principle explains why a long-term heroin user experiences little to no high from their usual dose but develops severe withdrawal if they stop?

Answer: Neuroadaptation: receptor down-regulation and decreased sensitivity with physical dependence

Chronic opioid use causes neuroadaptation — mu receptor down-regulation and reduced sensitivity — producing tolerance to euphoric effects while physical dependence develops independently.

PCP (phencyclidine) and ketamine produce dissociative effects primarily by:

Answer: Blocking NMDA glutamate receptors

PCP and ketamine act as NMDA receptor antagonists, blocking glutamate activity and producing dissociation, hallucinations, and analgesia.

Naltrexone is used in alcohol use disorder treatment because it:

Answer: Blocks opioid receptors, reducing the euphoric and reinforcing effects of alcohol

Naltrexone blocks mu opioid receptors, attenuating the dopamine release and euphoria triggered by alcohol, thereby reducing reinforcement and cravings.