USMLE® Step 1 Question of the Day: Duloxetine

This week, we are sharing another USMLE® Step 1-style practice question to test your knowledge of medical topics. Today's case focuses on a 49-year-old woman battling depression with a family history of mental health issues. Discover the critical factors that may make duloxetine the preferred treatment option for her condition. Get insights into her medical history and lifestyle choices that impact her overall well-being.

A 49-year-old woman comes to her outpatient provider because of a depressed mood that has persisted for several months. She also cites reduced sleep, frequent nighttime awakenings, reduced appetite, and a 2 kg (4.4 lb) weight loss. Her partner notes that she has been irritable and no longer enjoys going camping or playing with her dogs. Her maternal uncle died by suicide at the age of 30, and her mother has a history of generalized anxiety disorder. Past medical history is notable for hypercholesterolemia, hypertension, and type II diabetes mellitus. She smokes one pack of cigarettes per day. Her temperature is 37.0°C (98.6°F), her pulse is 80/min, respirations are 16/min, and her blood pressure is 155/77 mmHg. Which of the following additional findings in this patient would make duloxetine the treatment of choice?

A. Sexual dysfunction

B. Desire to quit smoking

C. History of bulimia nervosa

D. Sensory loss in the bilateral lower limbs

E. History of insomnia

Scroll down for the correct answer!

The correct answer to today's USMLE® Step 1 Question is...

D. Sensory loss in the bilateral lower limbs

Before we get to the Main Explanation, let's look at the incorrect answer explanations. Skip to the bottom if you want to see the correct answer right away!

Incorrect answer explanations

A. Sexual dysfunction

Incorrect: Bupropion inhibits norepinephrine and dopamine reuptake and is used as an atypical antidepressant. The medication has a favorable sexual side effect profile and can be used as an alternative to SSRIs and SNRIs. In contrast, SSRIs and SNRIs are likely to cause sexual dysfunction and decreased libido.

B. Desire to quit smoking

Incorrect: Bupropion is an atypical antidepressant that can treat the major depressive disorder and promote smoking cessation. In contrast, duloxetine does not have the same effect on smoking cessation.

C. History of bulimia nervosa

Incorrect: Mirtazapine is an α2-antagonist that promotes weight gain. As a result, it is preferred in treating major depressive disorder in patients with a history of anorexia or bulimia nervosa. 

E. History of insomnia 

Incorrect: Trazodone has sedative properties since it is an antagonist at 5-HT2 and H1 receptors. It can be used in patients with major depressive disorder and concurrent insomnia. In contrast, duloxetine and other SNRIs would likely exacerbate the patient’s insomnia.

Main Explanation

This patient has symptoms consistent with major depressive disorder (MDD), such as depressed mood, loss of appetite, sleep disturbances, loss of interest in previously enjoyable activities, and increased irritability. Duloxetine, a serotonin norepinephrine reuptake inhibitor (SNRI), is useful in treating MDD and concurrent diabetic neuropathy.

Diabetic neuropathy can cause sensory loss, motor weakness, and a burning sensation in the extremities. Duloxetine can exert analgesic properties by increasing norepinephrine and serotonin activity, which prevents excess pain stimuli from reaching the brain. As a result, duloxetine is useful in treating conditions associated with chronic pain, such as diabetic neuropathy and fibromyalgia.

P.S. If you or someone you know needs this, here's the number for the National Suicide Prevention Lifeline 1-800-273-8255 or text HOME to the Crisis Text Line at 741741.

Major Takeaway

Diabetic neuropathy can present with sensory loss, motor weakness, and a burning sensation in the extremities. Duloxetine is the treatment of choice in patients who have MDD and concurrent diabetic neuropathy.

References

Bril, V., England, J., Franklin, G.M., et al. (2011) Evidence-based guideline: Treatment of painful diabetic neuropathy: report of the American Academy of Neurology, the American Association of Neuromuscular and Electrodiagnostic Medicine, and the American Academy of Physical Medicine and Rehabilitation. Neurology. 76(20), 1758-1765. Doi: 10.1212/WNL.0b013e3182166ebe.

Dhaliwal, J.S., Spurling, B.C., Molla, M. (2020) “Duloxetine”. StatPearls [Internet]. Web Address: https://www.ncbi.nlm.nih.gov/books/NBK549806/.

Jameson, J. L. (2018). Harrison's principles of internal medicine. New York: McGraw-Hill Education. ISBN: 9781259644030.

Pop-Busui, R., Boulton, A.J.M, Feldman, E.L., et al. (2017) Diabetic neuropathy: A position statement by the American Diabetes Association. Diabetes Care. 40(1), 136-154. Doi: 10.2337/dc16-2042.

Trevor, A., Katzung, B., Knuidering-Hall, M. (2015). Katzung & Trevor's Pharmacology: Examination & Board Review, 11th ed. McGraw-Hill. ISBN: 978-0-07-182635-8.

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