Fluoxetine

Fluoxetine is a prescription medicine used to treat depression, obsessive compulsive disorder (OCD), bulimia, and panic disorder. Fluoxetine is also used to treat Premenstrual Dysphoric Disorder (PMDD).

Fluoxetine belongs to a group of drugs called selective serotonin reuptake inhibitor (SSRI). It works by changing the levels of certain chemicals in the brain that affect your mood.

CYP2D6 is a protein in your body that is involved in the elimination of fluoxetine and other drugs from your body. Some patients have less of this protein in their bodies, affecting how much of the drug gets eliminated. Levels of CYP2D6 can vary greatly between individuals, and those having less of this protein are known as "poor metabolizers." 

CYP2D6 testing is done to determine whether you are a poor metabolizer. If you are a poor metabolizer, the levels of fluoxetine in your blood can become too high. As a result you may be at an increased risk of having more side effects from fluoxetine. 

Your doctor should use caution in treating you with fluoxetine or your doctor may adjust your dose if you are a poor metabolizer.

Fluoxetine is a prescription medicine used to treat the following conditions:

• Depression (known medically as major depressive disorder (MDD) or clinical depression)
• Obsessive compulsive disorder (OCD) 
• Bulimia nervosa 
• Panic disorder 
• Depression associated with bipolar disorder, taken with olanzapine (Symbyax) 
• Treatment-resistant depression (depression that has not gotten better with at least 2 other treatments), taken with olanzapine (Symbyax) 
• Premenstrual Dysphoric Disorder (PMDD)

This medication may be prescribed for other uses. Ask your doctor or pharmacist for more information.

Fluoxetine may be found in some form under the following brand names:

• Prozac

• Prozac Weekly

• Reconcile

• Sarafem

• Selfemra

• Symbyax

Fluoxetine may cause serious side effects. See "Drug Precautions" section.

Common possible side effects in people who take fluoxetine include: 

• unusual dreams 
• sexual problems 
• loss of appetite, diarrhea, indigestion, nausea or vomiting, weakness, or dry mouth 
• flu symptoms 
• feeling tired or fatigued 
• change in sleep habits
• yawning 
• sinus infection or sore throat 
• tremor or shaking 
• sweating 
• feeling anxious or nervous 
• hot flashes 
• rash 

• increased thirst 
• abnormal increase in muscle movement or agitation 
• nose bleed 
• urinating more often 
• heavy menstrual periods 
• possible slowed growth rate and weight change. Your child’s height and weight should be monitored during treatment with fluoxetine

Tell your doctor about all the medicines you take including prescription and non-prescription medicines, vitamins, and herbal supplements. Especially tell your doctor if you take:

• Triptans used to treat migraine headache 
• Medicines used to treat mood, anxiety, psychotic or thought disorders, including tricyclics, lithium, SSRIs, SNRIs, MAOI’s (including linezolid, an antibiotic), or antipsychotics 
• Tramadol 
• Over-the-counter supplements such as tryptophan or St. John’s Wort 

If you take fluoxetine, you should not take any other medicines that contain fluoxetine including: 

• Symbyax 
• Sarafem 
• Prozac Weekly

This is not a complete list of fluoxetine drug interactions. Ask your doctor or pharmacist for more information

Fluoxetine and some medicines may interact with each other, may not work as well, or may cause serious side effects. Your healthcare provider or pharmacist can tell you if it is safe to take fluoxetine with your other medicines. Do not start or stop any medicine while taking fluoxetine without talking to your healthcare provider first.

Fluoxetine and other antidepressant medicines may cause serious side effects, including:

1. Suicidal thoughts or actions:

• Fluoxetine and other antidepressant medicines may increase suicidal thoughts or actions in some children, teenagers, or young adults within the first few months of treatment or when the dose is changed.
• Depression or other serious mental illnesses are the most important causes of suicidal thoughts or actions.
• Watch for these changes and call your healthcare provider right away if you notice:
  • New or sudden changes in mood, behavior, actions, thoughts, or feelings, especially if severe.
  • Pay particular attention to such changes when fluoxetine is started or when the dose is changed.

Keep all follow-up visits with your healthcare provider and call between visits if you are worried about symptoms.

Call your healthcare provider right away if you have any of the following symptoms, or call 911 if an emergency, especially if they are new, worse, or worry you:

• attempts to commit suicide
• acting on dangerous impulses
• acting aggressive or violent
• thoughts about suicide or dying
• new or worse depression
• new or worse anxiety or panic attacks
• feeling agitated, restless, angry or irritable
• trouble sleeping
• an increase in activity or talking more than what is normal for you
• other unusual changes in behavior or mood

Call your healthcare provider right away if you have any of the following symptoms, or call 911 if an emergency. Fluoxetine may be associated with these serious side effects:

2. Serotonin Syndrome or Neuroleptic Malignant Syndrome-like reactions. This condition can be life-threatening and may include:

• agitation, hallucinations, coma or other changes in mental status
• coordination problems or muscle twitching (overactive reflexes)
• racing heartbeat
• high or low blood pressure
• sweating or fever
• nausea, vomiting, or diarrhea
• muscle rigidity

3. Severe allergic reactions:

• trouble breathing
• swelling of the face, tongue, eyes or mouth
• rash, itchy welts (hives) or blisters, alone or with fever or joint pain

4. Abnormal bleeding: fluoxetine and other antidepressant medicines may increase your risk of bleeding or bruising, especially if you take the blood thinner warfarin (Coumadin, Jantoven), a non-steroidal anti-inflammatory drug (NSAIDs, like ibuprofen or naproxen), or aspirin.

5. Seizures or convulsions

6. Manic episodes:

• greatly increased energy
• severe trouble sleeping
• racing thoughts
• reckless behavior
• unusually grand ideas
• excessive happiness or irritability
• talking more or faster than usual

7. Changes in appetite or weight. Children and adolescents should have height and weight monitored during treatment.

8. Low salt (sodium) levels in the blood. Elderly people may be at greater risk for this. Symptoms may include:

• headache
• weakness or feeling unsteady
• confusion, problems concentrating or thinking or memory problems

Do not stop fluoxetine without first talking to your healthcare provider. Stopping fluoxetine too quickly may cause serious symptoms including:

• anxiety, irritability, high or low mood, feeling restless or changes in sleep habits
• headache, sweating, nausea, dizziness
• electric shock-like sensations, shaking, confusion

Do not take fluoxetine if you: 

• are allergic to any ingredient of fluoxetine capsules or solution (liquid). Ask your pharmacist for a complete list of ingredients.
• take a Monoamine Oxidase Inhibitor (MAOI). 
• take Mellaril (thioridazine). Do not take Mellaril within 5 weeks of stopping fluoxetine because this can cause serious heart rhythm problems or sudden death. 
• take the antipsychotic medicine pimozide (Orap) because this can cause serious heart problems.

Other precautions:

• Do not take an MAOI within 5 weeks of stopping fluoxetine. 
• Do not start fluoxetine if you stopped taking an MAOI in the last 2 weeks. People who take fluoxetine close in time to an MAOI may have serious or even life threatening side effects. Get medical help right away if you have any of these symptoms:
  • high fever 
  • uncontrolled muscle spasms 
  • stiff muscles 
  • rapid changes in heart rate or blood pressure 
  • confusion 
  • loss of consciousness (pass out) 

Medicines can interact with certain foods. In some cases, this may be harmful and your doctor may advise you to avoid certain foods. In the case of fluoxetine there are no specific foods that you must exclude from your diet when receiving fluoxetine.

Before starting fluoxetine, tell your healthcare provider if you: 

• Are taking certain drugs or treatments such as:
  • Triptans used to treat migraine headache 
  • Medicines used to treat mood, anxiety, psychotic or thought disorders, including tricyclics, lithium, SSRIs, SNRIs, MAOI’s (including linezolid, an antibiotic), or antipsychotics 
  • Tramadol 
  • Over-the-counter supplements such as tryptophan or St. John’s Wort 
  • Electroconvulsive therapy (ECT) 
• have liver problems 
• have kidney problems 
• have heart problems 
• have or had seizures or convulsions 
• have bipolar disorder or mania 
• have low sodium levels in your blood 
• have a history of a stroke 
• have high blood pressure 
• have or had bleeding problems 
• are pregnant or breastfeeding

Tell your doctor if you are pregnant or plan to become pregnant.

The FDA categorizes medications based on safety for use during pregnancy. Five categories - A, B, C, D, and X, are used to classify the possible risks to an unborn baby when a medication is taken during pregnancy.

Fluoxetine falls into category C. In animal studies, pregnant animals were given this medication and had some babies born with problems. No well-controlled studies have been done in humans, though. Therefore, this medication may be used if the potential benefits to the mother outweigh the potential risks to the unborn child.

Tell your doctor if you are breastfeeding or plan to breastfeed. 

Fluoxetine has been detected in human breast milk. Because of the possibility for adverse reactions in nursing infants from fluoxetine, a choice should be made whether to stop nursing or to stop use of this medication. The importance of the drug to the mother should be considered.

• Take fluoxetine exactly as prescribed. Your doctor may need to change (adjust) the dose of fluoxetine until it is right for you.
• If you miss a dose of fluoxetine, take the missed dose as soon as you remember. If it is almost time for the next dose, skip the missed dose and take your next dose at the regular time. Do not take two doses of fluoxetine at the same time.
• To prevent serious side effects, do not stop taking fluoxetine suddenly. If you need to stop taking fluoxetine, your doctor can tell you how to safely stop taking it.
• If you take too much fluoxetine, call your doctor or poison control center right away, or get emergency treatment.
• Fluoxetine is usually taken once or twice a day, with or without food.
• Fluoxetine is also available as delayed release capsules which can be given once weekly.
• If you do not think you are getting better or have any concerns about your condition while taking fluoxetine, call your doctor.

Take fluoxetine exactly as prescribed by your doctor. Follow the directions on your prescription label carefully.

The dosage of fluoxetine must be individualized based on your age, the condition being treated, other medications you are taking, and other medical conditions you may have.

For adults, fluoxetine doses range from 20 mg to 80 mg, taken once a day or taken as divided doses.

Your doctor may start you on a low dose of fluoxetine and gradually increase your dose.

• It may take more than 4 weeks before you feel the full benefit of fluoxetine.
• Do not stop taking fluoxetine until you talk to your doctor.
• If you need to stop taking fluoxetine, your doctor will probably decrease your dose gradually.

To recommended dose of fluoxetine (Sarafem) for the treatment of Premenstrual Dysphoric Disorder (PMDD) is 20 mg once a day, either every day of the month or on certain days of the month.

If you take too much fluoxetine call your local Poison Control Center or seek emergency medical attention right away.

• Store fluoxetine at room temperature between 59°F and 86°F (15°C to 30°C). 
• Keep fluoxetine away from light. 
• Keep fluoxetine bottle closed tightly. 
• Keep fluoxetine and all medicines out of the reach of children.

WARNING–SUICIDALITY AND ANTIDEPRESSANT DRUGS

Antidepressants increased the risk compared to placebo of suicidal thinking and behavior (suicidality) in children, adolescents, and young adults in short-term studies of Major Depressive Disorder (MDD) and other psychiatric disorders. Anyone considering the use of fluoxetine or any other antidepressant in a child, adolescent, or young adult must balance this risk with the clinical need. Short-term studies did not show an increase in the risk of suicidality with antidepressants compared to placebo in adults beyond age 24; there was a reduction in risk with antidepressants compared to placebo in adults aged 65 and older. Depression and certain other psychiatric disorders are themselves associated with increases in the risk of suicide. Patients of all ages who are started on antidepressant therapy should be monitored appropriately and observed closely for clinical worsening, suicidality, or unusual changes in behavior. Families and caregivers should be advised of the need for close observation and communication with the prescriber. Fluoxetine is approved for use in pediatric patients with MDD and Obsessive Compulsive Disorder (OCD). 

When using fluoxetine and olanzapine in combination, also refer to Boxed Warning section of the package insert for olanzapine and fluoxetine hydrochloride capsules.