Trazodone

Summary

Trazodone is a medication that works as an antagonist at 5-HT2 serotonin receptors, alpha-1 receptors, and H1 histamine receptors. Trazodone also weakly inhibits serotonin reuptake.

Clinically, trazodone is given at low doses to treat insomnia. Higher doses are needed to treat depression.

Side effects of trazodone include sedation, orthostatic hypotension, nausea, serotonin syndrome, and priapism.

Key Points

• Trazodone
  • Mechanism
    • Blocks 5-HT2 receptors
      • Modulates but generally antagonizes 5-HT2 serotonin receptors
      • Also weakly inhibits serotonin reuptake
    • Blocks H1 receptors
      • Accounts for sedative use in treating insomnia
    • Alpha-1 Blocker
  • Clinical Use
    • Treats depression (atypical antidepressant)
      • Used to treat depression in patients with insomnia
      • Usually high doses of trazodone are required to treat major depressive disorder
    • Treats insomnia
      • Due to sedative effects
  • Side Effects
    • Causes Sedation
    • Causes Priapism
      • Priapism refers to an erection lasting more than four hours independent of sexual arousal. Priapism is a dangerous condition because if left untreated it can lead to penile ischemia.  
    • Causes Orthostatic Hypotension
      • Due to blockade of  alpha-1 receptors
    • Causes Nausea
    • Causes Serotonin Syndrome
      • Especially when used with other serotonin-modulating drugs (SSRIs, SNRIs, MAOIs, TCA’s, etc.)