Side Effects of Prozac (Fluoxetine) for Bipolar Disorder

Adverse Reactions When Prozac Is Used to Treat Bipolar Disorder

Prozac capsule
What are the side effects of Prozac (fluoxetine)?. Jonathan Nourok Collection/The Image Bank/Getty Images

If your doctor has prescribed Prozac (fluoxetine) for bipolar disorder (or Symbyax which is a medication that combines Prozac with another drug) what symptoms might you expect? What adverse reactions are common, and which are less common but no less important? What do you need to know about overdoses on this drug and what kind of withdrawal symptoms may you experience?

Prozac for Bipolar Disorder

Prozac is commonly used to treat the anxiety disorders which are thought to occur in at least half of people with bipolar disorder, as well as co-existing depression.

The UK-based National Institute for Health and Care Excellence (NICE) put out an updated clinical guideline in late 2014 stating that Prozac (fluoxetine) is the only effective antidepressant for treating bipolar disorder, but only when used along with the antipsychotic Zyprexa (olanzapine). In the past, NICE had always recommended classes of medications as a whole and didn't target any specific kinds.

Specifically, a study that NICE headed up showed that the combination of Prozac and Zyprexa was the most clinically helpful, as well as the most cost-effective. The study also found that other antidepressants alone were ineffective and that Zyprexa alone was effective but more effective combined with Prozac. A medication combining these two medications—Prozac and Zyprexa—in one pill, is now available under the name Symbyax.

Prozac (Fluoxetine) for Panic Disorder

Prozac (fluoxetine) is a selective serotonin reuptake inhibitor (SSRI), which is a class of antidepressant medications that may be prescribed for the treatment of depression, bipolar disorder, and other mental illnesses.

The side effects are wide-ranging from minor to serious. If you are taking Prozac, you should be aware of the potential side effects.

This is important for people with bipolar disorder who are taking Symbyax as well, as this medication is a combination of Prozac (fluoxetine) and the antipsychotic drug Zyprexa.

Common Side Effects of Prozac

The following side effects are fairly common while taking Prozac. Check with your doctor if any of the following Prozac side effects don't go away or are bothersome:

  • Anxiety or nervousness
  • Sexual dysfunction ranging from low libido to erectile dysfunction to anorgasmia
  • Decreased appetite
  • Diarrhea
  • Drowsiness
  • Headache
  • Increased sweating
  • Nausea
  • Weakness
  • Trembling or shaking
  • Trouble sleeping

Rare Side Effects of Prozac

Less common side effects while taking Prozac may include:

  • Abnormal dreams
  • Change in sense of taste
  • Changes in vision
  • Chest pain
  • Constipation
  • Dizziness or lightheadedness
  • Dryness of mouth
  • Flushing or redness of your skin, especially on your face and neck
  • Frequent urination
  • Hair loss
  • Increased appetite
  • Stomach cramps, gas, nausea, or vomiting

Let Your Doctor Know About These Side Effects

Some adverse reactions to Prozac are more concerning than others and may be a medical emergency. If you have any of the following side effects, be sure to let your doctor know right away. They include:

  • Skin rash, hives, or itching
  • Chills or fever
  • Hallucinations
  • Joint or muscle pain or stiffness
  • Seizures
  • Trouble breathing or swallowing
  • Swelling of your face, throat, tongue, lips, eyes, hands, feet, ankles or lower legs

Possible Withdrawal Effects of Prozac

Never go off of Prozac without speaking with your doctor first and tapering off gradually. Selective serotonin reuptake inhibitors (SSRI) such as Prozac can cause withdrawal symptoms when they are discontinued. This condition, known as SSRI discontinuation syndrome can be very uncomfortable but is not usually dangerous. SSRI discontinuation syndrome is more common with antidepressants with a shorter half-life than Prozac, such as Paxil or Zoloft, but may still occur at times, especially for those who have been on the medication for an extended period of time.

  If you have any of these withdrawal effects, contact your doctor:

  • Anxiety
  • Dizziness
  • Feeling that body or surroundings are turning
  • General feeling of discomfort or illness
  • Headache
  • Nausea
  • Sweating
  • Unusual tiredness or weakness

Prozac Overdose Effects

The effects of a Prozac overdose tend to be more severe than the side effects you may experience at a regular dose. Prozac overdose is usually more uncomfortable than dangerous, but it's important to contact your doctor if you experience any of these effects, including:

  • Agitation and restlessness
  • Convulsions (seizures)
  • Drowsiness
  • Fast heartbeat
  • Nausea and vomiting
  • Talking, feeling, and acting with excitement and activity you cannot control
  • Trembling or shaking

Other Possible Side Effects

Everyone is different and responds differently to medications, including the side effects of those drugs. There are many uncommon side effects not listed here, but which have been reported on occasion. If you notice any side effects while taking your medication, whether or not you suspect they are due to your medication or not, call your doctor.

Bottom Line on Side Effects of Prozac (Fluoxetine) for Bipolar Disorder

As with medications used for any other physical or psychological disorder, side effects are common and may interfere with your quality of life. Many times you will need to make a decision based on whether the side effects you are experiencing are acceptable given the benefits you receive from a drug.


Fava, G., Gatti, A., Belaise, C., Guidi, J., and E. Offidani. Withdrawal Symptoms after Selective Serotonin Reuptake Inhibitor Discontinuation: A Systematic Review. Psychotherapy and Psychosomatics. 2015. 84(2):72-81.

National Center for Health and Care Excellence (NICE). Bipolar Disorder Assessment and Management. Updated 02/16

U.S. National Library of Medicine. Medline Plus. Fluoxetine. Updated 11/15/14.