Free COMLEX Level 3 Questions

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Our SmartBank is not a typical qbank. Our questions contain thorough answers and explanations to help improve your understanding of the material. We explain the correct answer, as well as why the others options were incorrect. They are designed to help prepare you for the COMLEX Level 3 exam and for your career.

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Your First Free COMLEX Level 3 Question

A 52-year-old woman presents to the emergency department with her husband, who found her convulsing and unresponsive. He notes he found her this way after returning home and is unaware of how long she would have been in this state. She is reportedly on multiple medications; however, her husband is unaware of which ones. He states that she has a history of hypertension, major depressive disorder, and fibromyalgia. He notes a previous incident last year in which she was hospitalized for suicidal ideation. Vital signs reveal:

On examination, the patient appears to be breathing comfortably but is unarousable. Her face is noted to be flushed, and her skin is warm to the touch and dry. Her pupils are both dilated and minimally reactive to light. Neurologic examination reveals no clonus or hyperreflexia. A full neurological examination is otherwise unable to be completed secondary to her current condition. An ECG is obtained and reveals a QRS duration of 150 milliseconds and a QT interval of 590 milliseconds. The most appropriate treatment for this patient’s condition is

• A. dantrolene
• B. chlordiazepoxide
• C. flumazenil
• D. naloxone
• E. sodium bicarbonate

The Answer and Explanation

The correct answer is: E

This patient with a history of major depressive disorder and fibromyalgia presents unconscious with witnessed seizures. Her skin is warm to touch, and she has dilated pupils, tachycardia, and fever, all findings consistent with anticholinergic toxicity. An ECG shows evidence of QRS and QT prolongation, a hallmark finding in cardiotoxicity produced by tricyclic antidepressant (TCA) overdose. Additionally, the patient is hypotensive, which is extremely common due to alpha1 antagonism. TCA toxicity is associated with lethargy (or coma), seizures, signs of anticholinergic toxicity, refractory hypotension, and cardiac toxicity. Associated cardiotoxicity, evidenced by a widening of the QRS complex, conduction abnormalities (bundle branch or heart block), ventricular fibrillation, or ventricular tachycardia or refractory hypotension, should be treated promptly with sodium bicarbonate.

TCAs, such as amitriptyline, are a class of medications sometimes used in managing depression. With advancements in selective serotonin reuptake inhibitors, which may be a safer and more effective treatment for depression, TCAs are less commonly used; however, they are still first-line agents for many functional disorders, such as fibromyalgia and irritable bowel syndrome. There is a high risk of toxicity in overdose, which can be fatal if TCAs are mixed with selective serotonin reuptake inhibitors or monoamine oxidase inhibitors. As seen in this patient, severe toxicity may result in seizures, coma, and cardiotoxicity. Additional anticholinergic symptoms may include warmed, flushed skin; dilated pupils; confusion; and tachycardia. The cardiotoxicity most commonly manifests as widening of the QRS complex.

Sodium bicarbonate is the standard first-line treatment for TCA overdose, specifically when there is a concern for arrhythmias. Sodium bicarbonate helps by causing an increase in serum pH and an increase in extracellular sodium. The increase in serum pH makes the TCA less available to bind to sodium channels. The increase in the extracellular sodium concentration increases the electrochemical gradient across cardiac cell membranes, potentially attenuating the TCA-induced blockade of rapid sodium channels. Supportive care should always be used as an adjunct for treatment, including initiation of vasopressors and intubation as needed. Seizures are usually treated with benzodiazepines.

Symptoms and Treatments for Adverse Reactions to Psychiatric and Controlled Medications

Wrong Answer Explanations

Answer A: Dantrolene is a muscle relaxer that may be used in the treatment of muscle spasms or the treatment of neuroleptic malignant syndrome (NMS). NMS is a life-threatening reaction that may occur secondary to antipsychotic use and may have similar symptoms to TCA toxicity, such as fever, tachycardia, and somnolence. However, NMS is noted to have multiple additional neurologic symptoms, such as rigidity and extrapyramidal motor findings, which are not present in this case. The lack of these findings makes TCA overdose more likely.

Answer B: Chlordiazepoxide is a benzodiazepine that may have multiple uses, including for acute anxiety and the treatment of acute seizures. It may also be used in the treatment of serotonin syndrome, which may have a similar presentation to TCA toxicity, including confusion, rapid heart rate, and dilated pupils. This patient lacks the neuromuscular symptoms associated with serotonin syndromes, such as rigidity, clonus, and hyperreflexia, and has ECG findings most consistent with TCA toxicity. While a benzodiazepine may have been helpful while the patient was actively seizing, it would not have been indicated while she was somnolent in the emergency department.

Answer C: Flumazenil is administered to patients in whom a benzodiazepine overdose is suspected. Symptoms of benzodiazepine overdose may include respiratory depression, somnolence, hypothermia, and bradycardia. Flumazenil works by competitively inhibiting the activity at the benzodiazepine receptor site on the gamma-aminobutyric acid/benzodiazepine receptor complex. Although this patient presents with respiratory depression and somnolence, the signs of anticholinergic toxicity and QRS widening are more consistent with TCA overdose.

Answer D: Naloxone is given for opioid intoxication. It is a pure opioid antagonist that competes with and displaces opioids at opioid receptor sites. While opioid overdose may present in a similar manner as respiratory depression and somnolence, it would additionally present with pinpoint pupils (as opposed to dilated pupils). Additionally, ECG changes seen in the scenario with prolonged QRS are unlikely in pure opioid overdose.

Bottom Line: Sodium bicarbonate is the first-line therapy in tricyclic antidepressant intoxication when patients present with evidence of cardiotoxicity or refractory hypotension.

For more information, see:

• TCA poisoning: UpToDate
• Kerr GW, McGuffie AC, Wilkie S. Tricyclic antidepressant overdose: a review. Emerg Med J. 2001;18:236–241.

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