Pharmacology of Addictive Substances Flashcards

A patient with opioid use disorder on methadone maintenance is prescribed rifampin for tuberculosis. What pharmacokinetic interaction should the nurse anticipate?

Answer: Rifampin induces CYP3A4, reducing methadone levels and potentially precipitating withdrawal

Rifampin is a potent CYP3A4 inducer; it accelerates methadone metabolism, significantly lowering plasma levels and triggering withdrawal symptoms.

Which of the following best describes the pharmacological basis for using benzodiazepines to manage alcohol withdrawal?

Answer: Benzodiazepines mimic alcohol's action at GABA-A receptors, preventing hyperexcitability

Benzodiazepines are cross-tolerant with alcohol at GABA-A receptors, substituting for alcohol's CNS depressant effect and preventing seizures during withdrawal.

MDMA (ecstasy) primarily causes serotonin syndrome risk when combined with which class of medications?

Answer: Monoamine oxidase inhibitors (MAOIs)

MDMA causes massive serotonin release; MAOIs prevent serotonin breakdown, leading to life-threatening serotonin syndrome when combined.

Varenicline (Chantix) reduces nicotine craving through which pharmacological mechanism?

Answer: Partial agonism at α4β2 nicotinic receptors, providing modest dopamine release while blocking nicotine

Varenicline is a partial agonist at α4β2 nicotinic receptors, providing enough dopamine stimulation to reduce craving while competitively blocking nicotine's full effect.

PCP (phencyclidine) produces its dissociative and psychotic effects primarily through which mechanism?

Answer: Antagonism of NMDA glutamate receptors

PCP blocks NMDA glutamate receptors (a dissociative mechanism), producing hallucinations, agitation, analgesia, and psychosis-like symptoms.

A patient stabilized on buprenorphine presents requesting pain management for a dental procedure. Which analgesic approach is most appropriate?

Answer: Continue buprenorphine and use non-opioid analgesics or regional anesthesia

Buprenorphine's high receptor affinity blocks full opioids; continuing it with non-opioid analgesics or regional techniques provides analgesia without compromising addiction treatment.

Which physiological effect explains why GHB (gamma-hydroxybutyrate) is particularly dangerous when combined with alcohol?

Answer: Synergistic CNS depression due to both agents enhancing GABA activity

Both GHB and alcohol enhance GABAergic CNS depression; their combination produces synergistic respiratory depression and sedation, greatly increasing overdose risk.