Pharmacology of Substance Use Flashcards

Which neurotransmitter system is primarily responsible for the euphoric reinforcement produced by opioids?

Answer: Dopamine in the mesolimbic pathway

Opioids activate mu-receptors on GABA interneurons, disinhibiting dopaminergic neurons in the ventral tegmental area and flooding the nucleus accumbens with dopamine.

A client taking methadone for OUD is prescribed erythromycin for a bacterial infection. The primary pharmacological concern is:

Answer: QTc interval prolongation due to combined CYP3A4 inhibition

Both methadone and erythromycin prolong the QT interval; erythromycin also inhibits CYP3A4, raising methadone plasma levels and amplifying cardiac risk.

Which benzodiazepine property makes it most likely to produce severe withdrawal seizures upon abrupt discontinuation?

Answer: Short half-life with high potency

Short-acting, high-potency benzodiazepines (e.g., alprazolam, triazolam) produce rapid CNS re-excitation upon discontinuation, greatly increasing seizure risk.

Cocaine's mechanism of action primarily involves:

Answer: Blocking reuptake of dopamine, norepinephrine, and serotonin

Cocaine blocks monoamine transporter proteins (DAT, NET, SERT), preventing reuptake and accumulating catecholamines in the synapse.

Naltrexone is contraindicated in a client who:

Answer: Used heroin within the past 7–10 days

Naltrexone will precipitate acute opioid withdrawal in opioid-dependent clients; a minimum 7–10 day abstinence from short-acting opioids is required before initiation.

Which statement best describes the pharmacokinetics of inhaled crack cocaine compared to intranasal powder cocaine?

Answer: Smoked crack reaches peak brain concentration in seconds, producing a more intense but shorter high

Pulmonary absorption bypasses first-pass metabolism and delivers cocaine to the brain within 8–10 seconds, creating an intense rush that dissipates rapidly and drives compulsive redosing.

The Wernicke-Korsakoff syndrome seen in chronic alcohol users is caused by deficiency of:

Answer: Thiamine (vitamin B1)

Alcohol impairs thiamine absorption and utilization; deficiency damages the thalamus and mammillary bodies, producing Wernicke's encephalopathy and, if untreated, Korsakoff's psychosis.