Atypical antidepressants

00:00 / 00:00


Atypical antidepressants


0 / 12 complete

USMLE® Step 1 questions

0 / 6 complete

USMLE® Step 2 questions

0 / 12 complete


Atypical antidepressants

of complete


USMLE® Step 1 style questions USMLE

of complete

USMLE® Step 2 style questions USMLE

of complete

A 30-year-old man with long standing major depressive disorder and insomnia presents to the emergency room with a chief complaint of right upper abdominal pain and dark urine. The patient has taken several antidepressants over the years, including selective serotonin reuptake inhibitors, serotonin norepinephrine reuptake inhibitors, and atypical antidepressants. The patient cannot remember the most recent medication that he is taking. Upon further evaluation, the patient also endorses dry mouth, nausea and constipation. Vitals are within normal limits. Physical examination reveals scleral icterus as well as slight jaundice of the tongue and skin. Which antidepressant is most likely responsible for this patient’s presentation?  

External References

First Aid








Bupropion p. 600

major depressive disorder p. 584

mechanism p. 598

nicotine withdrawal p. 595

seizures with p. 252

Dopamine p. 243, 334

bupropion effect p. 600

Headache p. 536

bupropion toxicity p. 600

Norepinephrine (NE)

bupropion effect on p. 600

Seizures p. 535

bupropion p. 600


bupropion for cessation p. 600


Atypical antidepressants are mainly used to treat major depressive disorder. This disorder causes a persistent feeling of sadness and loss of interest in everyday activities. Even though the exact cause of depression is still unknown, there's some evidence that suggests it’s related to low levels of neurotransmitters like serotonin, norepinephrine, and dopamine. Typical antidepressants like selective serotonin reuptake inhibitors or tricyclic antidepressants work by increasing the levels of serotonin and norepinephrine, while atypical antidepressants often have multiple mechanisms of action.

All right, now within the brain, there are many different types of neurons, but we’re going to focus only on three: serotonergic neurons, which produce serotonin; noradrenergic neurons, which produce norepinephrine; and dopaminergic neurons, which produce dopamine. Each of these neurons synthesizes and stores their neurotransmitters in small vesicles. So, when an action potential reaches the presynaptic membrane, these vesicles fuse with the membrane, releasing neurotransmitters into the synaptic cleft. Once released, serotonin (or 5-HT) binds to 5-HT2 receptors on the postsynaptic membrane, thereby increasing neural stimulation, and regulating mood, feeding, and reproductive behavior. On the other hand, norepinephrine binds to norepinephrine receptors on the postsynaptic membrane, boosting alertness. And finally, dopamine binds to dopamine receptors, thereby stimulating cognitive functions, motivation, and awakeness.


Atypical antidepressants are a class of antidepressant drugs that are distinguished from traditional, older antidepressant medications by their unique mechanism of action. They are generally reserved for cases that do not respond to other antidepressants. The atypical antidepressants include drugs like agomelatine, mirtazapine, and bupropion.

Atypical antidepressants are generally better tolerated than older drugs, and they are often just as effective. They are not without their side effects, however. The most common side effects of atypical antidepressants include nausea, headaches, anxiety, insomnia, and sexual dysfunction.


  1. "Katzung & Trevor's Pharmacology Examination and Board Review,12th Edition" McGraw-Hill Education / Medical (2018)
  2. "Rang and Dale's Pharmacology" Elsevier (2019)
  3. "Goodman and Gilman's The Pharmacological Basis of Therapeutics, 13th Edition" McGraw-Hill Education / Medical (2017)
  4. "Clinical guidance for the use of trazodone in major depressive disorder and concomitant conditions: pharmacology and clinical practice" Rivista di Psichiatria (2019)
  5. "A review of trazodone use in psychiatric and medical conditions" Postgraduate Medicine (2016)
  6. "Bupropion Hydrochloride" Profiles of Drug Substances, Excipients and Related Methodology (2016)
  7. "Vortioxetine for depression in adults" Cochrane Database of Systematic Reviews (2017)
  8. "Efficacy and safety of levomilnacipran, vilazodone and vortioxetine compared with other second-generation antidepressants for major depressive disorder in adults: A systematic review and network meta-analysis" Journal of Affective Disorders (2018)

Copyright © 2023 Elsevier, its licensors, and contributors. All rights are reserved, including those for text and data mining, AI training, and similar technologies.

Cookies are used by this site.

USMLE® is a joint program of the Federation of State Medical Boards (FSMB) and the National Board of Medical Examiners (NBME). COMLEX-USA® is a registered trademark of The National Board of Osteopathic Medical Examiners, Inc. NCLEX-RN® is a registered trademark of the National Council of State Boards of Nursing, Inc. Test names and other trademarks are the property of the respective trademark holders. None of the trademark holders are endorsed by nor affiliated with Osmosis or this website.