USMLE Step 1 Question of the Day

Practice USMLE Step 1 with the production-style question-of-the-day selection for this public URL.

Question 1

A 45-year-old man with major depressive disorder and tobacco use disorder started bupropion SR 150 mg twice daily 3 weeks ago. He reports improved concentration and decreased cigarette cravings without sexual side effects. Past medical history includes hypertension and obesity; he denies seizures, eating disorders, or alcohol misuse. Examination is normal. Labs: fasting glucose 108 mg/dL, lipid panel borderline, TSH normal, and creatinine 0.9 mg/dL. He notes mild insomnia and dry mouth. EKG is normal. He asks about how this antidepressant works, given the lack of sexual dysfunction. Weight is unchanged, and blood pressure is well controlled on lisinopril. He does not drink caffeine late in the day.

This medication's therapeutic effect is mediated through which mechanism?

Selective inhibition of the serotonin reuptake transporter
Irreversible inhibition of monoamine oxidase A
Antagonism of 5-HT2C and H1 receptors
Lowers the seizure threshold
Inhibition of norepinephrine and dopamine reuptake transporters

Explanation: Bupropion inhibits NE and dopamine reuptake, improving depression and aiding smoking cessation with minimal sexual dysfunction. SERT inhibition (A), MAO-A inhibition (B), and 5-HT2C/H1 antagonism (C) are other antidepressant mechanisms, and lowering the seizure threshold (D) is an ADR, not the therapeutic mechanism.

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USMLE Step 1

USMLE Step 1 Question of the Day

Practice USMLE Step 1 with the production-style question-of-the-day selection for this public URL.

Question 1

A 45-year-old man with major depressive disorder and tobacco use disorder started bupropion SR 150 mg twice daily 3 weeks ago. He reports improved concentration and decreased cigarette cravings without sexual side effects. Past medical history includes hypertension and obesity; he denies seizures, eating disorders, or alcohol misuse. Examination is normal. Labs: fasting glucose 108 mg/dL, lipid panel borderline, TSH normal, and creatinine 0.9 mg/dL. He notes mild insomnia and dry mouth. EKG is normal. He asks about how this antidepressant works, given the lack of sexual dysfunction. Weight is unchanged, and blood pressure is well controlled on lisinopril. He does not drink caffeine late in the day.

This medication's therapeutic effect is mediated through which mechanism?

Selective inhibition of the serotonin reuptake transporter
Irreversible inhibition of monoamine oxidase A
Antagonism of 5-HT2C and H1 receptors
Lowers the seizure threshold
Inhibition of norepinephrine and dopamine reuptake transporters

Explanation: Bupropion inhibits NE and dopamine reuptake, improving depression and aiding smoking cessation with minimal sexual dysfunction. SERT inhibition (A), MAO-A inhibition (B), and 5-HT2C/H1 antagonism (C) are other antidepressant mechanisms, and lowering the seizure threshold (D) is an ADR, not the therapeutic mechanism.