CARN Pharmacology & Substance Use Disorders 5 — Questions and Answers
Question 1: A patient with alcohol use disorder is started on gabapentin. What is the primary evidence-based rationale for this medication in this context?
- It directly blocks alcohol receptors in the brain
- It reduces alcohol craving and withdrawal symptoms by modulating calcium channels and glutamate (Correct answer)
- It is an FDA-approved first-line pharmacotherapy for AUD
- It increases acetaldehyde levels to deter drinking
Correct answer: It reduces alcohol craving and withdrawal symptoms by modulating calcium channels and glutamate
Gabapentin modulates voltage-gated calcium channels and reduces glutamate activity, helping manage protracted withdrawal symptoms and cravings, though it is not FDA-approved for AUD.
Question 2: The nurse is administering IV lorazepam to a patient in severe alcohol withdrawal. Which complication specific to IV lorazepam requires close monitoring?
- QTc prolongation
- Propylene glycol toxicity with high cumulative doses (Correct answer)
- Rhabdomyolysis
- Hypoglycemia
Correct answer: Propylene glycol toxicity with high cumulative doses
IV lorazepam formulations contain propylene glycol as a solvent, and high cumulative doses can cause propylene glycol toxicity including metabolic acidosis and renal injury.
Question 3: A patient reports using kratom daily to self-manage opioid cravings. The CARN nurse should recognize that kratom:
- Is an FDA-approved herbal supplement for opioid use disorder
- Contains alkaloids that act on opioid receptors and can cause dependence and withdrawal (Correct answer)
- Has no significant pharmacological activity
- Is classified as a Schedule II controlled substance in all US states
Correct answer: Contains alkaloids that act on opioid receptors and can cause dependence and withdrawal
Kratom contains mitragynine and 7-hydroxymitragynine, which bind opioid receptors; regular use can cause opioid-type dependence and withdrawal syndrome.
Question 4: Which statement about the pharmacology of cannabis is accurate regarding its effect on the endocannabinoid system?
- THC acts as an antagonist at CB1 receptors in the brain
- CBD is the primary psychoactive component responsible for the 'high'
- THC mimics endocannabinoids by acting as a CB1 and CB2 receptor partial agonist (Correct answer)
- Cannabis use increases endocannabinoid synthesis permanently
Correct answer: THC mimics endocannabinoids by acting as a CB1 and CB2 receptor partial agonist
THC acts as a partial agonist at CB1 (primarily CNS) and CB2 (primarily immune) receptors, mimicking endocannabinoids like anandamide to produce psychoactive and physiological effects.
Question 5: A patient with opioid use disorder on stable buprenorphine/naloxone is prescribed rifampin for tuberculosis. The nurse anticipates which medication adjustment?
- Decreasing buprenorphine dose due to reduced metabolism
- Increasing buprenorphine dose because rifampin strongly induces CYP3A4, lowering buprenorphine levels (Correct answer)
- Switching to methadone because rifampin inactivates buprenorphine
- No adjustment is needed as rifampin does not interact with buprenorphine
Correct answer: Increasing buprenorphine dose because rifampin strongly induces CYP3A4, lowering buprenorphine levels
Rifampin is a potent CYP3A4 inducer that significantly reduces buprenorphine plasma concentrations, often requiring a dose increase to maintain therapeutic effect.
Question 6: Gamma-hydroxybutyrate (GHB) withdrawal is most similar in presentation and management to withdrawal from which substance?
- Stimulants such as cocaine
- Opioids such as heroin
- Sedative-hypnotics such as alcohol and benzodiazepines (Correct answer)
- Hallucinogens such as LSD
Correct answer: Sedative-hypnotics such as alcohol and benzodiazepines
GHB acts on GABA-B receptors and GHB receptors; withdrawal produces CNS hyperexcitability similar to alcohol and benzodiazepine withdrawal, including seizures and delirium.
Question 7: A nurse is counseling a patient about naloxone home use. Which instruction is most important regarding repeat dosing?
- A single dose of naloxone is always sufficient and redosing is never needed
- Naloxone's duration of action may be shorter than the opioid's, requiring repeat doses every 2-3 minutes if the patient does not respond (Correct answer)
- Naloxone should only be given by healthcare professionals
- Naloxone should be administered orally for fastest onset
Correct answer: Naloxone's duration of action may be shorter than the opioid's, requiring repeat doses every 2-3 minutes if the patient does not respond
Naloxone's duration of action (30-90 minutes) is often shorter than many opioids, so repeat dosing every 2-3 minutes may be necessary, and emergency services must always be called.
CARN Pharmacology & Substance Use Disorders 5
A patient with alcohol use disorder is started on gabapentin.
What is the primary evidence-based rationale for this medication in this context?