Which intravenous agent should be avoided in a patient with a history of substance use disorder?

Correct answer: D. Fentanyl

• A. Nitrous oxide has some abuse potential but its extremely short duration and lack of take-home supply make it the safest sedative here.
• B. Propofol is not a controlled substance in most jurisdictions and has no meaningful street value, though it demands anaesthesia-level airway skills.
• C. Midazolam has abuse potential and its own cautions, but it is not the agent of greatest concern in an opioid-experienced patient. Benzodiazepines are, however, a serious concern with concurrent opioids because of respiratory depression.
• D. CORRECT. FENTANYL is a Schedule II opioid with very high abuse liability, and a patient in recovery from opioid dependence risks reactivating craving and relapse. Where an opioid is genuinely necessary the patient must be counselled, the exposure kept short, and their recovery support team informed.

Note: For a patient in recovery the principles are: prefer non-opioid analgesia (an NSAID and acetaminophen combination outperforms most opioids for dental pain), check the state Prescription Drug Monitoring Program, prescribe the smallest quantity if an opioid is unavoidable, and coordinate with their treating physician or sponsor rather than working around them.