Medicine & USMLE


Psych Pharm
  1. Lithium
  2. Typical Antipsychotics
  3. Atypical Antipsychotics
  4. SSRIs
  5. SNRIs
  6. Tricyclic Antidepressants (TCAs)
  7. Monoamine Oxidase Inhibitors (MAOIs)
  8. Bupropion
  9. Mirtazapine
  10. Trazadone
  11. Vilazodone
  12. Vortioxetine
  13. Buspirone
  14. Varenicline


Mirtazapine is a drug used to treat major depressive disorder. It acts as an antagonist or blocker at alpha-2 adrenergic receptors, serotonin and histamine receptors. Adverse effects of mirtazapine include sedation, weight gain, and dry mouth. These side effects are important in dictating the clinical use of the drug, as mirtazapine is preferred in depressed patients who are underweight or those who concurrently suffer from insomnia. 

Key Points

  • Mirtazapine
    • Mechanism
      • Acts as Alpha-2 antagonist
        • Increases the release of norepinephrine and serotonin 5-HT  
      • Acts as Serotonin receptor antagonist
        • Potent 5-HT2  and 5-HT3 serotonin receptor antagonist
      • Acts as H1 antagonist
    • Indications
      • Treats Depression
      • Treats Anorexia Nervosa
        • Causes weight gain as a side effect
    • Side Effects
      • Increased appetite and weight gain
        • Used in underweight patients or those with anorexia nervosa
      • Causes Sedation
        • Used in patients with insomnia