How Prozac (Fluoxetine) Is Used to Treat Bipolar Disorder

Prozac (fluoxetine) is a type of antidepressant known as a selective serotonin reuptake inhibitor (SSRI), which is often used for the treatment of depression, bipolar disorder, and other mental illnesses.

As useful as Prozac can be in treating these conditions, the drug may cause side effects ranging in severity from mild to life-threatening. Moreover, people who take Prozac may experience withdrawal symptoms if the treatment is not tapered off appropriately.

Use in Treating Anxiety Disorder

Prozac is commonly used to treat anxiety disorders, many of which can co-exist with bipolar disorder. These include generalized anxiety disorder (GAD), social anxiety disorder (SAD), panic disorder (PD), and post-traumatic stress disorder (PTSD)

In fact, a 2015 review of studies published in EBioMedicine concluded that the lifetime risk of an anxiety disorder co-occurring with bipolar disorder was 42.7%.

Within the context of bipolar disorder, Prozac is considered the only antidepressant with a formal indication in treating bipolar depression but only when used in combination with the antipsychotic drug Zyprexa (olanzapine).

Antidepressants need to be used with caution in bipolar disorder, as there is some evidence that they can trigger mania and worsen cycling of the disorder.

On the downside, the concomitant use of Prozac and Zyprexa also increases the risk of side effects.

Recommended Dosages

There is a fixed-dose combination drug called Symbyax which combines Prozac and Zyprexa in a convenient capsule formulation. Approved for adults in 2009 and children in 2013, Symbyax is usually prescribed at a lower dose and gradually increased until the depression symptoms resolve.

Ultimately, the aim of bipolar depression treatment is to alleviate symptoms at the lowest possible dose to reduce the risk of side effects.

Common Side Effects

Side effects are not uncommon when taking Prozac. Some are mild and transient and will often resolve as your body gradually adapts to the medication. 

Side effects of Prozac may include:

• Abdominal cramps and bloating
• Abnormal dreams
• Anxiety
• Constipation
• Diarrhea
• Dizziness or lightheadedness
• Drowsiness
• Dry mouth
• Sexual side effects
• Headaches
• Increased sweating
• Insomnia
• Loss of appetite
• Low libido
• Nausea and vomiting
• Tremors
• Weakness

Call your doctor if any of these side effects persist or worsen.

Drug Hypersensitivity

Some adverse reactions to Prozac may be serious and require emergency medical treatment. This is especially true if there are signs of a potentially life-threatening allergic response known as anaphylaxis.

Call 911 or seek immediate emergency care if you experience some or all of the following symptoms:

• Rash or hives
• Fever
• Facial swelling
• Swelling of the tongue and/or throat
• Trouble breathing
• Difficulty swallowing
• Disorientation and confusion
• Nausea and vomiting
• Rapid heart rate
• Fainting
• A feeling of impending doom

If left untreated, anaphylaxis can lead to shock, coma, respiratory or heart failure, and death.

Black Box Warning

Prozac and other antidepressants have been found to potentially increase suicidal thoughts or actions in some children, teenagers, or young adults. This usually occurs within the first few months of starting treatment or when the dose is changed. Call your doctor immediately if you notice any sudden or severe changes in mood, behavior, thoughts, or feelings.

Withdrawal Symptoms

It is important to never stop taking Prozac without first speaking with your doctor and working out a dosage reduction plan. Stopping treatment abruptly can lead to a form of drug withdrawal known as SSRI discontinuation syndrome.

While withdrawal is more common with shorter half-life antidepressants like Paxil (paroxetine) or Zoloft (sertraline), it can occasionally happen with the longer half-life Prozac, especially if you have been on treatment for a long time. SSRI withdrawal is rarely dangerous, but it can be extremely uncomfortable and distressing.

Symptoms typically include:

• Dizziness
• Extreme anxiety
• Fatigue
• Headaches
• Malaise
• Nausea and vomiting
• Profuse sweating
• Vertigo
• Headaches
• Weakness

If the decision is made to stop Prozac, you would need to taper down slowly. Your doctor can provide specific instructions as well as the appropriate dosage pills.