Prozac side effects

Dear Alice,

What are the long-term effects of taking Prozac? I've been taking 20 mg/day for almost a year.

— Happy, but at what cost?

Dear Happy, but at what cost?, 

Prozac (generic name: fluoxetine) is one of the most common antidepressants in the United States. It’s prescribed to treat major depressive disorder and obsessive-compulsive disorder in adults and children. It's also prescribed to treat panic disorder, bulimia nervosa, and premenstrual dysphoric disorder (PMDD). It’s in the selective serotonin reuptake inhibitor (SSRI) family of drugs, meaning it works by altering the action of the neurotransmitter serotonin. Fluoxetine is considered to have fewer side effects compared to other antidepressants, and short-term side effects typically — but not always — go away within one to two weeks from starting the medication. If they don’t, it’s wise to speak with a health care provider. 

That being said, there are some potential, but generally rare, long-term side effects to be aware of when taking fluoxetine: 

  • Reduced bone mineral density (BMD): There is some research that indicates that long-term SSRI use may contribute to reduced BMD. Because individuals using SSRIs may have reduced bone density, it could also lead to an increased risk of bone fractures, which is a symptom of osteoporosis. It’s thought that serotonin has a role in how the cells in this part of the body functions. Though there are some theories about the exact role of serotonin and its impact on bones, additional research is needed.  
  • Psoriasis: This chronic skin disease causes intermittent red, itchy patches on the skin. Studies on the impact of SSRIs, and fluoxetine specifically, have been mixed. Some show that use of such SSRIs may lead to, or exacerbate, psoriasis, while others show it might help enhance other psoriasis treatments and lead to a faster remission. It’s good to note that researchers have reported few cases of this long-term side effect.  
  • Sexual dysfunction: This could be considered both a short- and long-term effect. Fluoxetine often reduces sexual desire and can delay or interfere with orgasm, in both individuals assigned male and female at birth.  
  • Risk of suicidality: This risk is associated with beginning treatment with fluoxetine, but also anytime the dosage is increased or decreased throughout the duration of treatment. Previously thought to only affect users under the age of 25, fluoxetine is now considered to potentially increase the risk of suicide for anyone taking it. It’s critical that you communicate any changes in mood or suicidal thoughts to your prescribing provider so they can make any necessary modifications to your dosage.  

Although many of the side effects of fluoxetine use subside within a few weeks, some of the potential long-term side effects may last throughout the duration of use. It’s also possible that some side effects may continue after stopping the medication. These long-term side effects don’t occur in everyone, but if you’re concerned and want to stop using it, it’s best to talk with your health care provider first. Stopping fluoxetine is best (and safely) done under medical supervision. Quitting the medication abruptly or after a fast taper can also cause withdrawal symptoms or other unpleasant effects. If you're looking for more information about antidepressants or other medications, you may find the Medications section of the Go Ask Alice! Emotional Health archives to be helpful. 

Last updated Jul 30, 2021
Originally published Mar 08, 1996

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