Prozac®

What is Prozac?

Prozac is the brand name of the generic medication fluoxetine. It is approved to treat bulimia nervosa, major depressive disorder (MDD), obsessive-compulsive disorder (OCD), panic disorder (PD), and premenstrual dysphoric disorder (PMDD). 

Prozac also has many off-label uses. When a medication is prescribed for “off-label” use, this means it is being taken to treat a condition other than one that the Food and Drug Administration (FDA) has approved. Off-label use is a common and acceptable practice among healthcare providers.

Off-label uses of Prozac include:

• Binge eating disorder
• Body dysmorphic disorder
• Dysthymia
• Generalized anxiety disorder (GAD)
• Post-traumatic stress disorder (PTSD)
• Social anxiety disorder

Prozac is a selective serotonin reuptake inhibitor (SSRI). SSRIs, including Lexapro (escitalopram), Zoloft (sertraline), and Celexa (citalopram), are a type of medication typically used to treat depression, though they also treat anxiety. SSRIs work by boosting the brain’s level of serotonin (a type of neurotransmitter, or small molecule that sends messages between nerves). SSRIs increase the amount of serotonin available in your brain by preventing it from being reabsorbed and deactivated by the nerves in your brain (called neurons).

Serotonin helps balance your mood, affects your overall sense of wellbeing, and can improve feelings, such as contentment, optimism, and satisfaction.

Prozac (fluoxetine) is available in multiple forms and doses:

Prozac capsules

• 10 mg
• 20 mg
• 40 mg

Prozac Weekly Capsules

• 90 mg

Fluoxetine liquid

• 20 mg/5ml

Fluoxetine tablets

• 10 mg
• 20 mg
• 60 mg

A starting dose of dose of fluoxetine or Prozac usually is 20 mg. If needed, your doctor or prescribing nurse may increase your dosage gradually over the course of several weeks. Depending on the condition it is being prescribed for, the maximum recommended dose may be up to 80 mg daily, though some people need a higher dose than that for symptom relief.

Once you and your prescribing doctor or nurse feel that you are on the right dose to relieve your symptoms, you might consider discussing switching to the weekly dose version of Prozac rather than the daily version. In such instances, taking Prozac weekly is as effective as daily and reduces the burden of taking it.

With the exception of the weekly dose version, Prozac is usually taken once daily. It is typically taken in the morning, either with or without food.

If you accidentally miss your daily dose of Prozac, either:

• Take the missed dose as soon as you remember.
• Or, if it is closer to when you would take the next dose, just take the next dose.

If you accidentally miss your dose of the weekly Prozac, go ahead and take it as soon as you remember to and then resume your regular medication schedule.

For more information:

• Lexapro vs Prozac: which antidepressant is better?
• Zoloft vs Prozac: Which antidepressant is better for me?

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Prozac side effects, warnings, and drug interactions

Prozac side effects

Common side effects of Prozac include:

• Anxiousness
• Appetite loss
• Change in sleep habits
• Dry mouth
• Fatigue
• Flu-like symptoms
• Hot flashes
• Indigestion/diarrhea
• Nausea/vomiting
• Nightmares or unusual dreams
• Rash
• Sexual problems (such as decreased sex drive or sexual dysfunction)
• Sore throat/sinus infection
• Sweating
• Tremor/shaking
• Weakness
• Yawning

Many adverse effects of Prozac may improve within the first couple of weeks of starting it. However, sexual side effects may not disappear while you continue to use Prozac. 

If you experience these or any other new or worsening side effects, talk to your prescribing doctor, nurse, or Minded professional.

Rare or serious side effects of Prozac include:

• Angle-closure glaucoma (symptoms include: pain in your eye, vision changes, or swelling or redness in or around your eye)
• Arrhythmias (irregular heartbeat—symptoms include: shortness of breath, dizziness, or fainting)
• Low sodium levels in your blood (symptoms include: headaches, feeling weak, or having a hard time concentrating or remembering things)
• Seizures
• Serotonin Syndrome (symptoms include: shivering, diarrhea, confusion, severe tightness in your muscles, fever, or seizures. Serotonin Syndrome is serious—and it can be fatal if it is not properly diagnosed and treated.)
• Teeth grinding

SSRIs—including Prozac—may increase your risk for potentially life-threatening bleeding in your stomach, intestines, nose, gums, and other areas of your body. This risk may be higher if you also take certain other medications, including:

• Anticoagulants (such as Eliquis or Warfarin)
• Aspirin
• Nonsteroidal anti-inflammatories (NSAIDs, such as ibuprofen or naproxen)

Seek immediate medical attention if you experience these (or any other) serious side effect(s).

Prozac weight gain

There may be many causes for weight gain in people taking antidepressants—and not all of them are directly related to the medications themselves. However, in some cases, antidepressant medications—including Prozac—can cause weight gain. One 2016 study published in the Journal of Clinical Medicine found that people who took Prozac over a two-year period gained an average of 4.6 pounds. 

On the other hand, a 2015 study in General Hospital Psychiatry that looked at antidepressant use ranging from 6 months to 3 years found that while many antidepressants led to significant weight gain, Prozac was the lone exception that did not.

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Prozac weight loss

While some people experience weight gain, loss of appetite is a possible side effect of Prozac, which could potentially lead to weight loss. While there are few studies that look explicitly at weight loss and Prozac, one 2019 study did note that Prozac may lead to weight loss, though the authors noted that their findings were based on limited data.

Prozac interactions

Always let your doctor, prescribing nurse, or Minded professional know about all medications and supplements, like St. John's Wort, you are taking. This is important to determine if Prozac may have any potential negative interactions.

Prozac may interact with:

• Amphetamines
• Benzodiazepines, such as Valium (diazepam), Xanax (alprazolam), and Klonopin (clonazepam).
• Beta-blockers, such as Inderal (propranolol), Lopressor (metoprolol), or Toprol XL (metoprolol XL)
• Certain antipsychotics, such as Abilify (aripiprazole) or Haldol (haloperidol)
• Certain anticonvulsants, such as Dilantin (phenytoin), Equetro (carbamazepine), or Tegretol (carbamazepine)
• Codeine
• Coumadin (warfarin)
• Medications that may cause bleeding, such as Advil (ibuprofen), aspirin, or Motrin (ibuprofen)
• Migraine medications (triptans)
• Monoamine oxidase inhibitors (MAOIs—another type of antidepressant medication)
• Nolvadex (tamoxifen)
• Other selective serotonin reuptake inhibitors (SSRIs)
• Reglan (metoclopramide)
• Straterra (atomoxetine)
• Tricyclic antidepressants, such as Norpramin (desipramine) or Tofranil (imipramine)
• Zyvox (linezolid)

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Prozac and alcohol

You should not drink alcohol while you are taking Prozac (or antidepressants generally). Alcohol can both decrease the benefits of antidepressant medications and increase their negative side effects. If taken with alcohol, there is also a risk of accidentally overdosing on Prozac.

Prozac and other SSRI medications need to be taken regularly in order to effectively relieve depression symptoms and avoid withdrawal symptoms. You should not skip any doses of Prozac in order to drink alcohol.

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Prozac warnings

Prozac comes with an FDA “Black Box” warning. A Black Box warning means that the FDA has identified certain potentially serious safety risks that could occur from taking this medication. While these safety warnings are very serious, the actual risk can be low or even rare.

The Black Box Warning for Prozac says:

• Antidepressants might increase the risk of suicidal behaviors or thoughts in children, adolescents, and young adults under 25 years old.
• Prozac is not approved for use in children under 7 years old.

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Prozac and pregnancy

Talk to your doctor or prescribing nurse if you are pregnant or planning on becoming pregnant or breastfeeding. Because Prozac can be passed to your baby during pregnancy and through your breast milk, your treatment plan may need to be adjusted during this time.

Prozac withdrawal

If you have to stop taking Prozac for any reason, it is important that you work together with your prescribing doctor, nurse, or Minded provider to come up with a plan to carefully and gradually do so to avoid withdrawal symptoms.

Prozac withdrawal symptoms may include:

• Dizziness
• Headache
• Irritability
• Nausea
• Nightmares
• Paresthesias (a prickling and/or tingling sensation on your skin)
• Vomiting

While some people may have mild antidepressant medication withdrawal symptoms, other people experience severe symptoms that go on for weeks or even months. Following a careful plan that you and your provider develop together can help you avoid withdrawal symptoms.