Approximately 7 percent of adults in the United States are currently suffering from major depressive disorder, which is a serious mental health condition that can affect a person’s quality of life dramatically. 

Antidepressant medications like Prozac and Cymbalta are commonly prescribed for the treatment of major depressive disorder and other mental health conditions.

These medications are particularly effective when combined with talk therapy and lifestyle changes. 

While there are some similarities between the two drugs, there are also many differences, so we’ve put together a Cymbalta vs. Prozac comparison guide to help you understand the differences and similarities between the two medications.

Drug Class

Prozac and Cymbalta belong to two different drug classes. 

Prozac belongs to a class of prescription drugs called selective serotonin reuptake inhibitors (SSRIs), while Cymbalta belongs to a class of prescription drugs called serotonin-norepinephrine reuptake inhibitors (SNRIs).

Both are only available with a prescription from a healthcare provider. 

SSRIs and SNRIs are relative newcomers to the antidepressant market, with the first SSRI approved by the U.S. Food and Drug Administration (FDA) in 1987.

In fact, Prozac was the first SSRI on the market, and the medication revolutionized the way major depression was treated because SSRIs are typically better tolerated than earlier types of antidepressants. 

The first SNRI was introduced to the market in the early 1990s. 

Both SSRIs and SNRIs work by acting on the reuptake of different neurotransmitters in the brain that are known to affect mood.

This helps to increase the levels of these neurotransmitters, resulting in an improved or stabilized mood. 

Other SNRIs include venlafaxine (Effexor) and desvenlafaxine (Pristiq). Other SSRIs include citalopram (Celexa), paroxetine (Paxil), sertraline (Zoloft), and escitalopram (Lexapro). 

Conditions Treated

Cymbalta, sold under the generic name duloxetine, and Prozac, sold under the generic name fluoxetine, are both used for the treatment of major depressive disorder, which is sometimes referred to as clinical depression. 

Cymbalta can be used to treat depression in adults, while Prozac can be used to treat adults and children as young as eight years of age.

There are also other conditions treated by each medication that do not overlap.

Major Depressive Disorder

Major depressive disorder, sometimes referred to as MDD, is diagnosed when patients experience feelings of intense sadness that are persistent and last for a period of at least two weeks.

Major depressive disorder is a serious mental health condition that is known to cause a number of different mental, physical, and emotional symptoms that can significantly impact your body and your quality of life. 

People with major depressive disorder may notice that their typical behaviors change over time. 

For example, some people find that they eat more than usual while experiencing symptoms of depression, while other people find they may eat less.

Sleep patterns are also commonly disrupted, with some people sleeping more or less than usual. 

One very common experience in patients with major depressive disorder is a loss of interest in activities that they previously enjoyed, as well as difficulty performing simple daily tasks, such as tidying up, cooking meals, or bathing. It is also common for patients to have suicidal thoughts and tendencies. 

Symptoms of major depressive disorder include:

  • Feelings of worthlessness, guilt, hopelessness, or helplessness
  • Low energy levels
  • Sleepiness or less than usual sleep 
  • Eating more or less than usual
  • Weight loss
  • Feeling sad, empty, or tearful
  • Loss of interest in activities that were previously enjoyed
  • Difficulty concentrating
  • Suicidal thoughts or behaviors

Other Conditions Treated by Cymbalta

In addition to major depressive disorder, Cymbalta is also used for the treatment of generalized anxiety disorder, fibromyalgia, and diabetic peripheral neuropathy.  

Generalized anxiety disorder, or GAD, is a type of anxiety disorder that is defined by severe feelings of anxiety that persist for at least six months or more and disrupt a person’s daily quality of life.

Symptoms of generalized anxiety disorder can include difficulty falling asleep, restlessness, persistent worrying, and trouble concentrating. 

Fibromyalgia is a condition that is characterized by chronic widespread musculoskeletal pain that can occur anywhere on the body. There is often no identifiable cause for the chronic pain.

People with fibromyalgia often experience symptoms such as fatigue, tension headaches, memory issues, sleep problems, and mood changes. 

People with diabetes who are unable to manage their high blood sugar levels through medication may experience what is known as diabetic peripheral neuropathy.

Diabetic peripheral neuropathy causes nerve pain in the legs and feet.

People with diabetic neuropathy can experience symptoms like pain, tingling and numbness in the legs and feet, and increased sensitivity to touch. 

Other Conditions Treated by Prozac

In addition to treating major depressive disorder, Prozac is also used for the treatment of obsessive compulsive disorder (OCD), panic disorder, bulimia nervosa, and premenstrual dysphoric disorder (PMDD).

People with obsessive compulsive disorder, also known as OCD, experience persistent, obsessive thoughts that cause feelings of anxiety.

These thoughts are then linked to compulsive behaviors that are performed in an attempt to relieve the anxious thoughts. Obsessive compulsive disorder typically develops in childhood or early adulthood and may intensify later in life. 

Symptoms may include:

  • Fear of contamination
  • Anxiety about germs and dirt
  • Disturbing thoughts 
  • Need for symmetry and order, including obsessive cleanliness

Panic disorder is a type of anxiety disorder characterized by the frequent occurrence of panic attacks. Panic attacks are unexpected and repeated episodes of intense fear that can cause physical symptoms like chest pain, shortness of breath, heart palpitations, sweating, dizziness, and nausea.

Bulimia nervosa is a type of eating disorder in which a person binges on food, consuming an unusually large quantity in a short amount of time, and then purges the food through behaviors like vomiting, laxatives, or excessive exercise in order to prevent weight gain. 

Premenstrual dysphoric disorder (PMDD) is characterized by irritability, tension, and depression in the days preceding a woman’s menstrual period. While many women experience mild forms of these symptoms in the days before their period, those with PMDD experience symptoms in a severe fashion.

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Some studies have compared the effectiveness of Prozac to the effectiveness of Cymbalta. In general, these studies have found that Prozac and Cymbalta are similarly effective in the treatment of major depressive disorder. However,  some patients may find that one medication works better than the other based on their specific response to treatment.

In general, it may take several weeks for SSRIs and SNRIs to work effectively. Those who are prescribed Prozac or Cymbalta can expect to experience the full effects of either medication after approximately one month of taking the medication.

In some cases Prozac can be used to treat bipolar disorder when paired with another prescription drug called Zyprexa (olanzapine).

Side Effects

Common side effects associated with Prozac include:

  • Loss of appetite
  • Diarrhea
  • Indigestion
  • Nausea
  • Dry mouth
  • Yawning
  • Sinus infection
  • Tremors
  • Sweating
  • Unusual dreams
  • Sexual dysfunction
  • Drowsiness
  • Hot flashes

Rare but serious side effects associated with Prozac include:

  • Angle closure glaucoma with signs and symptoms such as::
    • Changes in vision
    • Eye pain
    • Swelling or redness in or around eye
  • Low sodium blood levels with signs and symptoms such as:
    • Headache
    • Confusion
    • Weakness
    • Difficulty concentrating
    • Restlessness
  • Serotonin syndrome with signs and symptoms such as:
    • Severe muscular tightness
    • Fever
    • Shivering
    • Diarrhea
    • Confusion
    • Seizures
  • QT prolongation and ventricular arrhythmia 
  • Abnormal bleeding
  • Seizures
  • Manic episodes
  • Allergic reactions


Common side effects associated with Cymbalta include:

  • Nausea
  • Dry mouth
  • Decreased appetite
  • Increased sweating
  • Vomiting
  • Diarrhea
  • Drowsiness
  • Constipation

Less common adverse effects that may occur while using Cymbalta include:

  • Liver problems
  • Orthostatic hypotension
  • Manic/hypomanic episodes
  • Glaucoma
  • Seizures
  • Increased blood pressure
  • Low sodium levels
  • Serotonin syndrome
  • Abnormal bleeding
  • Stevens-Johnson syndrome

If you experience any of these side effects, or side effects persist or worsen,seek medical advice from your healthcare provider. This may not be a complete list of side effects, warnings, or precautions.


Studies show that Cymbalta and Prozac are similarly effective in treating major depressive disorder in adults.

Prozac can also be used to treat major depressive disorder in patients as young as eight years old. 

Both medications are associated with similar side effects, and some patients may respond better to one medication than the other.

Both medications are available in both generic and brand name forms by prescription and are usually covered by commercial health insurance in their generic form.

Similar antidepressants include Zoloft, Lexapro, Paxil, and Effexor.  

Using a pharmacy discount card from can help you save money on your prescription regardless of which medication your doctor prescribes.

References, Studies and Sources:

author avatar
Angel Rivera
I am a Bilingual (Spanish) Psychiatrist with a mixture of strong clinical skills including Emergency Psychiatry, Consultation Liaison, Forensic Psychiatry, Telepsychiatry and Geriatric Psychiatry training in treatment of the elderly. I have training in EMR records thus very comfortable in working with computers. I served the difficult to treat patients in challenging environments in outpatient and inpatient settings

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