Toxicology And Poison Management
Comprehensive Medical Exam Review
300 Practice Questions With Detailed
Rationales 2026 Latest Just Released
SECTION 1: GENERAL TOXICOLOGY PRINCIPLES (Questions 1-
20)
Question 1 A 45-year-old male is brought to the emergency department
after ingesting an unknown substance found in his garage. He is drowsy but
arousable, with a heart rate of 110 bpm, blood pressure 160/95 mmHg,
respiratory rate 22/min, and temperature 38.5°C. His pupils are dilated to 6
mm bilaterally and sluggishly reactive. He has dry mucous membranes and
decreased bowel sounds. Which toxidrome is most consistent with this
presentation?
A) Cholinergic syndrome B) Opioid syndrome C) Anticholinergic
syndrome D) Sympathomimetic syndrome
Answer: C Explanation: This patient demonstrates the classic
anticholinergic toxidrome: "mad as a hatter" (delirium/agitation), "dry as a
bone" (dry mucous membranes, decreased sweating), "red as a beet"
(flushed skin), "blind as a bat" (mydriasis with blurred vision), and "hot as a
hare" (hyperthermia). The dilated pupils, dry mucous membranes, decreased
bowel sounds, and hyperthermia are characteristic of anticholinergic
toxicity. Sympathomimetic syndrome (D) would cause diaphoresis, not dry
skin. Opioid syndrome (B) causes miosis and bradycardia. Cholinergic
syndrome (A) would cause miosis, salivation, and diarrhea.
,
Question 2 A 28-year-old woman presents with confusion, vomiting, and
tachypnea after ingesting a large amount of her grandmother's arthritis
medication. Her arterial blood gas shows pH 7.28, PaCO2 28 mmHg, PaO2
98 mmHg, and HCO3 14 mEq/L. Which of the following is the most likely
ingested substance?
A) Acetaminophen B) Aspirin (salicylate) C) Ibuprofen D) Naproxen
Answer: B Explanation: Salicylate toxicity presents with a mixed
respiratory alkalosis and metabolic acidosis. The initial respiratory center
stimulation causes hyperventilation (respiratory alkalosis), followed by
metabolic acidosis from uncoupling of oxidative phosphorylation and
accumulation of organic acids. The anion gap is typically elevated. The
classic toxidrome includes tinnitus, nausea, vomiting, and altered mental
status. Acetaminophen (A) does not typically cause acid-base disturbances.
Ibuprofen (C) and naproxen (D) rarely cause significant acid-base
abnormalities in overdose.
Question 3 A 32-year-old man is brought to the ED following a witnessed
seizure. His friend reports he has been taking an antidepressant. Vital signs:
HR 120 bpm, BP 155/95 mmHg, RR 18/min, T 39.0°C. On examination, he
has clonus, hyperreflexia, and muscle rigidity. Which medication is most
likely responsible?
A) Fluoxetine B) Sertraline C) Paroxetine D) Venlafaxine
Answer: D Explanation: This presentation is consistent with serotonin
syndrome, characterized by mental status changes, autonomic instability,
and neuromuscular abnormalities. Venlafaxine (a serotonin-norepinephrine
reuptake inhibitor - SNRI) can cause serotonin syndrome, especially at
higher doses. SSRIs (fluoxetine, sertraline, paroxetine) can also cause
serotonin syndrome but are less likely to cause the severe presentation
,
described. The classic triad of serotonin syndrome includes altered mental
status, autonomic hyperactivity, and neuromuscular excitability (clonus,
hyperreflexia, rigidity, tremor).
Question 4 A 19-year-old college student is found unresponsive in her
dormitory room. Empty containers of "benzodiazepine" are found nearby.
Her pupils are pinpoint (1 mm). Her respiratory rate is 6/min. Naloxone is
administered with no response. What is the most appropriate next step in
management?
A) Administer flumazenil B) Increase naloxone dose C) Intubate and
provide ventilatory support D) Administer activated charcoal
Answer: C Explanation: This patient has severe respiratory depression
from benzodiazepine toxicity, as evidenced by pinpoint pupils (which may
occur with benzodiazepines but is more classically associated with opioids)
and lack of response to naloxone. The priority is airway management and
ventilatory support. Flumazenil (A) is a benzodiazepine antagonist but
should be used with extreme caution in chronic benzodiazepine users or in
mixed overdoses due to the risk of precipitating seizures. Ventilatory
support (C) is the safest and most appropriate first step. Increasing naloxone
dose (B) would be ineffective as the patient is not responding to opioid
antagonism. Activated charcoal (D) may be considered but airway
protection is the priority.
Question 5 A 55-year-old male with a history of depression and alcoholism
is brought to the ED after ingesting an unknown amount of his prescribed
medication. He is drowsy but responsive. His ECG shows a QRS duration
of 120 msec and a prolonged QTc interval. Which of the following
medications is most likely responsible?
A) Sertraline B) Bupropion C) Venlafaxine D) Amitriptyline
,
Answer: D Explanation: Tricyclic antidepressants (TCAs) such as
amitriptyline cause sodium channel blockade, resulting in QRS prolongation
(classically >100 msec) and QTc prolongation. TCA toxicity can also cause
seizures, arrhythmias, and anticholinergic effects. Bupropion (B) can cause
seizures but typically does not cause QRS prolongation. SSRIs like
sertraline (A) and venlafaxine (C) can cause QTc prolongation but are less
likely to cause significant QRS widening.
Question 6 A 23-year-old man is brought to the ED with altered mental
status. His friends report he took "ecstasy" at a rave. He is agitated,
diaphoretic, and has trismus. Temperature is 40.5°C, HR 150 bpm, BP
180/100 mmHg. Which of the following is the most appropriate immediate
intervention?
A) Haloperidol B) Benzodiazepines C) Cooling measures D) Dantrolene
Answer: C Explanation: This patient has severe hyperthermia from
MDMA (ecstasy) toxicity, which can be life-threatening. Immediate cooling
measures are the priority, including external cooling with cold water, ice
packs, and evaporative cooling. Benzodiazepines (B) may help control
agitation and seizures but do not directly address the hyperthermia.
Dantrolene (D) is used for malignant hyperthermia, not ecstasy toxicity.
Haloperidol (A) should be avoided as it can lower the seizure threshold and
worsen hyperthermia.
Question 7 A 65-year-old woman with chronic kidney disease presents with
fatigue, weakness, and constipation. She reports using an over-the-counter
medication for heartburn for several months. Laboratory findings show
calcium 11.2 mg/dL, phosphate 2.8 mg/dL, and elevated PTH. Which of the
following is the most likely cause?
Comprehensive Medical Exam Review
300 Practice Questions With Detailed
Rationales 2026 Latest Just Released
SECTION 1: GENERAL TOXICOLOGY PRINCIPLES (Questions 1-
20)
Question 1 A 45-year-old male is brought to the emergency department
after ingesting an unknown substance found in his garage. He is drowsy but
arousable, with a heart rate of 110 bpm, blood pressure 160/95 mmHg,
respiratory rate 22/min, and temperature 38.5°C. His pupils are dilated to 6
mm bilaterally and sluggishly reactive. He has dry mucous membranes and
decreased bowel sounds. Which toxidrome is most consistent with this
presentation?
A) Cholinergic syndrome B) Opioid syndrome C) Anticholinergic
syndrome D) Sympathomimetic syndrome
Answer: C Explanation: This patient demonstrates the classic
anticholinergic toxidrome: "mad as a hatter" (delirium/agitation), "dry as a
bone" (dry mucous membranes, decreased sweating), "red as a beet"
(flushed skin), "blind as a bat" (mydriasis with blurred vision), and "hot as a
hare" (hyperthermia). The dilated pupils, dry mucous membranes, decreased
bowel sounds, and hyperthermia are characteristic of anticholinergic
toxicity. Sympathomimetic syndrome (D) would cause diaphoresis, not dry
skin. Opioid syndrome (B) causes miosis and bradycardia. Cholinergic
syndrome (A) would cause miosis, salivation, and diarrhea.
,
Question 2 A 28-year-old woman presents with confusion, vomiting, and
tachypnea after ingesting a large amount of her grandmother's arthritis
medication. Her arterial blood gas shows pH 7.28, PaCO2 28 mmHg, PaO2
98 mmHg, and HCO3 14 mEq/L. Which of the following is the most likely
ingested substance?
A) Acetaminophen B) Aspirin (salicylate) C) Ibuprofen D) Naproxen
Answer: B Explanation: Salicylate toxicity presents with a mixed
respiratory alkalosis and metabolic acidosis. The initial respiratory center
stimulation causes hyperventilation (respiratory alkalosis), followed by
metabolic acidosis from uncoupling of oxidative phosphorylation and
accumulation of organic acids. The anion gap is typically elevated. The
classic toxidrome includes tinnitus, nausea, vomiting, and altered mental
status. Acetaminophen (A) does not typically cause acid-base disturbances.
Ibuprofen (C) and naproxen (D) rarely cause significant acid-base
abnormalities in overdose.
Question 3 A 32-year-old man is brought to the ED following a witnessed
seizure. His friend reports he has been taking an antidepressant. Vital signs:
HR 120 bpm, BP 155/95 mmHg, RR 18/min, T 39.0°C. On examination, he
has clonus, hyperreflexia, and muscle rigidity. Which medication is most
likely responsible?
A) Fluoxetine B) Sertraline C) Paroxetine D) Venlafaxine
Answer: D Explanation: This presentation is consistent with serotonin
syndrome, characterized by mental status changes, autonomic instability,
and neuromuscular abnormalities. Venlafaxine (a serotonin-norepinephrine
reuptake inhibitor - SNRI) can cause serotonin syndrome, especially at
higher doses. SSRIs (fluoxetine, sertraline, paroxetine) can also cause
serotonin syndrome but are less likely to cause the severe presentation
,
described. The classic triad of serotonin syndrome includes altered mental
status, autonomic hyperactivity, and neuromuscular excitability (clonus,
hyperreflexia, rigidity, tremor).
Question 4 A 19-year-old college student is found unresponsive in her
dormitory room. Empty containers of "benzodiazepine" are found nearby.
Her pupils are pinpoint (1 mm). Her respiratory rate is 6/min. Naloxone is
administered with no response. What is the most appropriate next step in
management?
A) Administer flumazenil B) Increase naloxone dose C) Intubate and
provide ventilatory support D) Administer activated charcoal
Answer: C Explanation: This patient has severe respiratory depression
from benzodiazepine toxicity, as evidenced by pinpoint pupils (which may
occur with benzodiazepines but is more classically associated with opioids)
and lack of response to naloxone. The priority is airway management and
ventilatory support. Flumazenil (A) is a benzodiazepine antagonist but
should be used with extreme caution in chronic benzodiazepine users or in
mixed overdoses due to the risk of precipitating seizures. Ventilatory
support (C) is the safest and most appropriate first step. Increasing naloxone
dose (B) would be ineffective as the patient is not responding to opioid
antagonism. Activated charcoal (D) may be considered but airway
protection is the priority.
Question 5 A 55-year-old male with a history of depression and alcoholism
is brought to the ED after ingesting an unknown amount of his prescribed
medication. He is drowsy but responsive. His ECG shows a QRS duration
of 120 msec and a prolonged QTc interval. Which of the following
medications is most likely responsible?
A) Sertraline B) Bupropion C) Venlafaxine D) Amitriptyline
,
Answer: D Explanation: Tricyclic antidepressants (TCAs) such as
amitriptyline cause sodium channel blockade, resulting in QRS prolongation
(classically >100 msec) and QTc prolongation. TCA toxicity can also cause
seizures, arrhythmias, and anticholinergic effects. Bupropion (B) can cause
seizures but typically does not cause QRS prolongation. SSRIs like
sertraline (A) and venlafaxine (C) can cause QTc prolongation but are less
likely to cause significant QRS widening.
Question 6 A 23-year-old man is brought to the ED with altered mental
status. His friends report he took "ecstasy" at a rave. He is agitated,
diaphoretic, and has trismus. Temperature is 40.5°C, HR 150 bpm, BP
180/100 mmHg. Which of the following is the most appropriate immediate
intervention?
A) Haloperidol B) Benzodiazepines C) Cooling measures D) Dantrolene
Answer: C Explanation: This patient has severe hyperthermia from
MDMA (ecstasy) toxicity, which can be life-threatening. Immediate cooling
measures are the priority, including external cooling with cold water, ice
packs, and evaporative cooling. Benzodiazepines (B) may help control
agitation and seizures but do not directly address the hyperthermia.
Dantrolene (D) is used for malignant hyperthermia, not ecstasy toxicity.
Haloperidol (A) should be avoided as it can lower the seizure threshold and
worsen hyperthermia.
Question 7 A 65-year-old woman with chronic kidney disease presents with
fatigue, weakness, and constipation. She reports using an over-the-counter
medication for heartburn for several months. Laboratory findings show
calcium 11.2 mg/dL, phosphate 2.8 mg/dL, and elevated PTH. Which of the
following is the most likely cause?
