Dental MCQ
CNS depressants and substance use · Pharmacology · INBDE Patient Cases

Sedatives, Anxiolytics & Drugs of Abuse INBDE Patient Cases

By Dr. Isaac Sun, DDS

9 ADA INBDE-format patient cases on sedatives, anxiolytics & drugs of abuse. Each case is a shared patient box (chief complaint, history, medications, allergies, exam) followed by linked multiple-choice questions with full distractor explanations. Practice the way the real exam is structured.

9 patient cases45 linked questionsADA INBDE formatFull distractor explanations

Nine ADA INBDE-format patient cases on sedative, anxiolytic, and drugs-of-abuse pharmacology: triazolam potentiated by grapefruit and azoles through CYP3A4 (with flumazenil reversal), additive benzodiazepine plus opioid respiratory depression, nitrous oxide diffusion hypoxia and chronic vitamin B12 inactivation in recreational abuse, ketamine NMDA-antagonist dissociative sedation with sympathomimetic HR/BP rise and emergence reactions reduced by benzodiazepine premedication, ethanol with metronidazole producing a disulfiram-like reaction and with warfarin raising the INR, acute cocaine intoxication contraindicating routine epinephrine through stacked sympathomimetic effects, chronic methamphetamine producing 'meth mouth' rampant caries, acute cannabis tachycardia and xerostomia complicating elective sedation, and benzodiazepines on the Beers criteria for older adults. Topics include GABA-A pharmacology, nitrous oxide, ketamine, ethanol metabolism, opioid abuse and naloxone, sympathomimetic drugs of abuse, and the cannabis dental encounter.

Case Coverage Map
What each case is testing
Triazolam, grapefruit juice, and prolonged sedation:
CYP3A4 substrate triazolam potentiated by grapefruit/azoles/macrolides, flumazenil reversal with re-sedation monitoring, and LOT benzodiazepines that bypass CYP.
Additive respiratory depression with benzodiazepine + opioid:
Stacked CNS/respiratory depression, airway-first management, titrated naloxone + flumazenil, and prospective dose and monitoring rules.
Diffusion hypoxia after nitrous oxide:
NMDA antagonism mechanism, end-of-case 100% oxygen, contraindications (air-filled spaces), and chronic B12 inactivation in recreational abuse.
Ketamine sedation and the emergence reaction:
NMDA antagonism, sympathomimetic HR/BP rise, salivation, emergence reaction blunted by benzodiazepine premedication, and appropriate setting.
Ethanol, metronidazole, and warfarin in the same patient:
Disulfiram-like aldehyde-DH inhibition, metronidazole + warfarin INR rise, chronic ethanol + acetaminophen NAPQI, and benzodiazepine withdrawal first-line.
Acute cocaine intoxication and the epinephrine caution:
NE reuptake block, epi stacking → hypertensive crisis, defer elective work, vasoconstrictor-free LA when needed, and recovery patient management.
Methamphetamine and 'meth mouth':
Catecholamine release mechanism, multifactorial caries (xerostomia/bruxism/sugar), epi caution in acute use, and recovery-patient restorative plan.
Acute cannabis intoxication chairside:
CB1 agonism, tachycardia + dry mouth + anxiety, defer elective work + minimum epi for urgent care, and chronic-use xerostomia and gingival inflammation.
Benzodiazepines and fall risk in an older adult:
Beers criteria fall/fracture/confusion risk, start low + go slow + transport home, lorazepam phase II metabolism, iatrosedation + nitrous oxide alternatives.
Patient case: Triazolam, grapefruit juice, and prolonged sedation
0 of 5 answered, 0 correct
Patient
Female, 52 years old
Chief Complaint
Prolonged sedation after a triazolam-assisted dental appointment.
Background and/or Patient History
  • Took prescribed triazolam the night before and the morning of a dental appointment for anxiety
  • Started a new azole antifungal for a fungal infection
  • Also reports a habit of grapefruit juice with breakfast
Allergies
NKDA
Medications
  • Triazolam (prescribed PRN)
  • Fluconazole (recent)
Current Findings
  • Prolonged, deeper sedation than expected
  • CYP3A4 inhibitors stacking with triazolam
  1. Question 1
    Hard
    The likely cause of prolonged sedation is:
  2. Question 2
    Moderate
    Other CYP3A4 inhibitors that potentiate triazolam include:
  3. Question 3
    Easy
    If sedation deepens to compromise airway, the reversal agent is:
  4. Question 4
    Moderate
    For future appointments, the dentist should:
  5. Question 5
    Easy
    The teaching point is that triazolam's effect depends heavily on:

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Patient case: Additive respiratory depression with benzodiazepine + opioid
0 of 5 answered, 0 correct
Patient
Male, 60 years old
Chief Complaint
Profound sedation and slow respirations after sedation with a benzodiazepine plus an opioid.
Background and/or Patient History
  • Moderate sedation for an extraction using IV midazolam and IV fentanyl
  • Patient becomes deeply sedated with respiratory rate 6 and SpO2 88%
  • Naloxone and flumazenil considered
Allergies
NKDA
Medications
  • Midazolam (sedation)
  • Fentanyl (sedation)
Current Findings
  • Profound sedation with respiratory depression
  • Likely additive benzodiazepine + opioid effect
  1. Question 1
    Moderate
    Combining a benzodiazepine with an opioid for sedation produces:
  2. Question 2
    Moderate
    The initial management of this episode is:
  3. Question 3
    Moderate
    If reversal is needed, the appropriate agents are:
  4. Question 4
    Moderate
    Once awake, the patient is monitored for:
  5. Question 5
    Moderate
    Prospectively, the safer practice is to:

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Patient case: Diffusion hypoxia after nitrous oxide
0 of 5 answered, 0 correct
Patient
Male, 16 years old
Chief Complaint
Routine restorative procedure with nitrous oxide; transient dip in oxygen saturation noted in recovery.
Background and/or Patient History
  • Healthy adolescent receiving 30 percent nitrous oxide in oxygen during a restorative procedure
  • Saturation transiently dropped to 92 percent when the mask was removed at the end
  • Question of diffusion hypoxia
Allergies
NKDA
Medications
  • None
Current Findings
  • Transient saturation dip after nitrous oxide cessation
  • Discussion of end-of-case 100% oxygen
  1. Question 1
    Moderate
    The likely cause of the saturation dip is:
  2. Question 2
    Moderate
    The simple preventive step is:
  3. Question 3
    Moderate
    Nitrous oxide acts mainly as:
  4. Question 4
    Hard
    Contraindications to nitrous oxide include:
  5. Question 5
    Hard
    Chronic recreational nitrous oxide abuse can produce:

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Patient case: Ketamine sedation and the emergence reaction
0 of 5 answered, 0 correct
Patient
Female, 8 years old
Chief Complaint
Pediatric procedural sedation considered for an uncooperative dental case.
Background and/or Patient History
  • Healthy child requiring restorative work that cannot be done with behavioral methods alone
  • Discussion of IM/IV ketamine as part of a sedation plan in the appropriate setting
  • Family asked about side effects
Allergies
NKDA
Medications
  • None
Current Findings
  • Pediatric sedation candidate (with appropriate setting and training)
  • Ketamine pharmacology focus
  1. Question 1
    Moderate
    Ketamine produces analgesia and dissociative anesthesia by:
  2. Question 2
    Hard
    Hemodynamically, ketamine typically:
  3. Question 3
    Moderate
    Salivation under ketamine is often:
  4. Question 4
    Moderate
    The 'emergence reaction' (vivid dreams, hallucinations) on waking from ketamine is reduced by:
  5. Question 5
    Easy
    The teaching point is that ketamine is best used:

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Patient case: Ethanol, metronidazole, and warfarin in the same patient
0 of 5 answered, 0 correct
Patient
Male, 65 years old
Chief Complaint
Severe nausea and flushing after a drink while taking metronidazole for a dental infection; also on warfarin.
Background and/or Patient History
  • Atrial fibrillation on warfarin
  • Habitual nightly alcohol use
  • Recent metronidazole course for a dental anaerobic infection
Allergies
NKDA
Medications
  • Warfarin
  • Metronidazole (current)
Current Findings
  • Disulfiram-like reaction from metronidazole + alcohol
  • Concurrent INR-raising interaction
  1. Question 1
    Moderate
    The flushing and nausea after a drink while on metronidazole are caused by:
  2. Question 2
    Moderate
    The metronidazole-warfarin interaction is also expected to:
  3. Question 3
    Hard
    Chronic heavy ethanol use also raises ACETAMINOPHEN hepatotoxicity risk because chronic ethanol:
  4. Question 4
    Moderate
    Ethanol withdrawal in a chronic heavy user is treated first-line with:
  5. Question 5
    Easy
    The teaching point is that this patient illustrates:

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Patient case: Acute cocaine intoxication and the epinephrine caution
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Patient
Male, 30 years old
Chief Complaint
Walks in with palpitations and chest tightness; admits to using cocaine an hour earlier.
Background and/or Patient History
  • Came in for a dental emergency
  • Tachycardia at 130, BP 180/108
  • Reports cocaine use an hour ago
Allergies
NKDA
Medications
  • None
Current Findings
  • Acute cocaine intoxication with tachycardia and hypertension
  • Local anesthetic + vasoconstrictor decision
  1. Question 1
    Moderate
    Cocaine produces its sympathomimetic effect by:
  2. Question 2
    Hard
    Routine epinephrine in local anesthetic is unsafe now because:
  3. Question 3
    Moderate
    Elective dental work for this patient should:
  4. Question 4
    Hard
    If a procedure is unavoidable, the local anesthetic plan is to:
  5. Question 5
    Easy
    Once the patient is in long-term recovery and stable, dental care can:

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Patient case: Methamphetamine and 'meth mouth'
0 of 5 answered, 0 correct
Patient
Female, 27 years old
Chief Complaint
Rampant cervical and smooth-surface caries on examination; admits to methamphetamine use.
Background and/or Patient History
  • Heavy methamphetamine use over the past several years
  • Examination shows rampant cervical and smooth-surface caries on multiple teeth
  • Severe xerostomia on examination
Allergies
NKDA
Medications
  • None reported
Current Findings
  • Rampant 'meth mouth' caries pattern
  • Xerostomia, bruxism stigmata
  1. Question 1
    Moderate
    Methamphetamine produces its sympathomimetic effect by:
  2. Question 2
    Moderate
    The 'meth mouth' caries pattern is driven by:
  3. Question 3
    Moderate
    Acute methamphetamine intoxication interacts with epinephrine to:
  4. Question 4
    Easy
    Long-term dental management of a patient in recovery includes:
  5. Question 5
    Moderate
    Elective dental work during ACUTE methamphetamine intoxication should:

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Patient case: Acute cannabis intoxication chairside
0 of 5 answered, 0 correct
Patient
Male, 22 years old
Chief Complaint
Tachycardia, dry mouth, and anxiety after using cannabis shortly before a routine appointment.
Background and/or Patient History
  • Used cannabis (smoked) about 30 minutes before arrival
  • Tachycardia at 110, dry mouth, mild anxiety
  • Requested local anesthesia and a restorative procedure
Allergies
NKDA
Medications
  • None reported
Current Findings
  • Acute cannabis intoxication
  • Tachycardia, xerostomia, anxiety
  1. Question 1
    Moderate
    THC (delta-9-tetrahydrocannabinol) acts mainly at:
  2. Question 2
    Moderate
    Acute cannabis intoxication can complicate elective dental sedation because:
  3. Question 3
    Moderate
    The dental decision in this case is to:
  4. Question 4
    Moderate
    Chronic cannabis use is also associated dentally with:
  5. Question 5
    Easy
    The teaching point is that substance use changes:

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Patient case: Benzodiazepines and fall risk in an older adult
0 of 5 answered, 0 correct
Patient
Female, 82 years old
Chief Complaint
Family asks about a benzodiazepine for dental anxiety; she lives alone and has a history of falls.
Background and/or Patient History
  • Lives alone with a history of falls
  • Anxious about an upcoming complex restorative appointment
  • Family asks about a triazolam prescription
Allergies
NKDA
Medications
  • Diuretic
  • Calcium channel blocker
Current Findings
  • Older adult with fall risk
  • Benzodiazepine appropriateness question
  1. Question 1
    Moderate
    In the elderly, benzodiazepines are associated with:
  2. Question 2
    Moderate
    If a benzodiazepine is used in an older adult, the principles are to:
  3. Question 3
    Easy
    Non-pharmacologic anxiolysis in the elderly includes:
  4. Question 4
    Moderate
    Nitrous oxide as an anxiolytic in an older adult:
  5. Question 5
    Easy
    The teaching point is that benzodiazepine use in the elderly:

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Sedatives, Anxiolytics & Drugs of Abuse core recall

Refresh the anatomy facts these cases depend on: nerve numbers, foramina, functions, and lesion findings.

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