Immunomodulatory effects of fluoxetine: A new potential pharmacological action for a classic antidepressant drug?

Pharmacol Res. 2016 Jul;109:101-7. doi: 10.1016/j.phrs.2015.11.021. Epub 2015 Nov 28.


Selective serotonin reuptake inhibitors are frequently used antidepressants. In particular, fluoxetine is usually chosen for the treatment of the symptoms of depression, obsessive-compulsive, panic attack and bulimia nervosa. Antidepressant therapy has been associated with immune dysfunction. However, there is contradictory evidence about the effect of fluoxetine on the immune system. Experimental findings indicate that lymphocytes express the serotonin transporter. Moreover it has been shown that fluoxetine is able to modulate the immune function through a serotonin-dependent pathway and through a novel independent mechanism. In addition, several studies have shown that fluoxetine can alter tumor cell viability. Thus, it was recently demonstrated in vivo that chronic fluoxetine treatment inhibits tumor growth by increasing antitumor T-cell activity. Here we briefly review some of the literature referring to how fluoxetine is able to modify, for better or worse, the functionality of the immune system. These results of our analysis point to the relevance of the novel pharmacological action of this drug as an immunomodulator helping to treat several pathologies in which immune deficiency and/or deregulation is present.

Keywords: Antidepressant; Fluoxetine; Immune system; Immunomodulation; Serotonin.

Publication types

  • Review
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Antidepressive Agents / pharmacology*
  • Antidepressive Agents / therapeutic use
  • Fluoxetine / pharmacology*
  • Fluoxetine / therapeutic use
  • Homeostasis / drug effects
  • Humans
  • Immunologic Factors / pharmacology*
  • Immunologic Factors / therapeutic use
  • Serotonin / metabolism


  • Antidepressive Agents
  • Immunologic Factors
  • Fluoxetine
  • Serotonin