Fluoxetine: Uses & Side Effects

Fluoxetine is a selective serotonin reuptake inhibitor (SSRI) antidepressant. Fluoxetine affects chemicals in the brain that may be unbalanced in people with depression, panic, anxiety, or obsessive-compulsive symptoms.

Fluoxetine is used to treat major depressive disorder, bulimia nervosa (an eating disorder), obsessive-compulsive disorder, panic disorder, and premenstrual dysphoric disorder (PMDD).

Fluoxetine is sometimes used together with another medication called olanzapine (Zyprexa) to treat manic depression caused by bipolar disorder. This combination is also used to treat depression after at least 2 other medications have been tried without successful treatment of symptoms.

If you also take olanzapine (Zyprexa), read the Zyprexa medication guide and all patient warnings and instructions provided with that medication.

How should I take fluoxetine?

Take fluoxetine exactly as prescribed by your doctor. Follow all directions on your prescription label. Your doctor may occasionally change your dose. Do not take this medicine in larger or smaller amounts or for longer than recommended.

Do not crush, chew, break, or open a delayed-release capsule. Swallow it whole.

Measure liquid medicine with the dosing syringe provided, or with a special dose-measuring spoon or medicine cup. If you do not have a dose-measuring device, ask your pharmacist for one.

To treat premenstrual dysphoric disorder, the usual dose of fluoxetine is once daily while you are having your period, or 14 days before you expect your period to start. Follow your doctor’s instructions.

It may take up to 4 weeks before your symptoms improve. Keep using the medication as directed and tell your doctor if your symptoms do not improve.

Do not stop using fluoxetine suddenly, or you could have unpleasant withdrawal symptoms. Ask your doctor how to safely stop using fluoxetine.

Store at room temperature away from moisture and heat.

Precautions

Do not use fluoxetine if you have taken a MAO inhibitor in the past 14 days. A dangerous drug interaction could occur. MAO inhibitors include isocarboxazid, linezolid, phenelzine, rasagiline, selegiline, and tranylcypromine. You must wait at least 14 days after stopping an MAO inhibitor before you can take fluoxetine. You must wait 5 weeks after stopping fluoxetine before you can take thioridazine or an MAOI.

You should not use fluoxetine if you are allergic to it, if you also take pimozide or thioridazine, or if you are being treated with methylene blue injection.

Tell your doctor about all other antidepressants you take, especially Celexa, Cymbalta, Desyrel, Effexor, Lexapro, Luvox, Oleptro, Paxil, Pexeva, Symbyax, Viibryd, or Zoloft.

Some medicines can interact with fluoxetine and cause a serious condition called serotonin syndrome. Be sure your doctor knows about all other medicines you use. Ask your doctor before making any changes in how or when you take your medications.

To make sure fluoxetine is safe for you, tell your doctor if you have:

  • cirrhosis of the liver;
  • kidney disease;
  • diabetes;
  • narrow-angle glaucoma;
  • seizures or epilepsy;
  • bipolar disorder (manic depression);
  • a history of drug abuse or suicidal thoughts;
  • if you are being treated with electroconvulsive therapy (ECT).

Some young people have thoughts about suicide when first taking an antidepressant. Your doctor should check your progress at regular visits. Your family or other caregivers should also be alert to changes in your mood or symptoms.

Taking an SSRI antidepressant during pregnancy may cause serious lung problems or other complications in the baby. However, you may have a relapse of depression if you stop taking your antidepressant. Tell your doctor right away if you become pregnant. Do not start or stop taking fluoxetine during pregnancy without your doctor’s advice.

Fluoxetine can pass into breast milk. Tell your doctor if you are breast-feeding a baby.

Fluoxetine is not approved for use by anyone younger than 18 years old.

Side Effects

Get emergency medical help if you have signs of an allergic reaction to fluoxetine: skin rash or hives; difficulty breathing; swelling of your face, lips, tongue, or throat.

Report any new or worsening symptoms to your doctor, such as: mood or behavior changes, anxiety, panic attacks, trouble sleeping, or if you feel impulsive, irritable, agitated, hostile, aggressive, restless, hyperactive (mentally or physically), more depressed, or have thoughts about suicide or hurting yourself.

Call your doctor at once if you have:

  • blurred vision, tunnel vision, eye pain or swelling, or seeing halos around lights;
  • signs of high levels of serotonin in the body–agitation, hallucinations, fever, fast heart rate, overactive reflexes, nausea, vomiting, diarrhea, loss of coordination, fainting;
  • signs of low levels of sodium in the body–headache, confusion, slurred speech, severe weakness, vomiting, loss of coordination, feeling unsteady;
  • very stiff (rigid) muscles, high fever, sweating, confusion, fast or uneven heartbeats, tremors, feeling like you might pass out;
  • severe skin reaction–fever, sore throat, swelling in your face or tongue, burning in your eyes, skin pain, followed by a red or purple skin rash that spreads (especially in the face or upper body) and causes blistering and peeling.

Common fluoxetine side effects may include:

  • sleep problems (insomnia), strange dreams;
  • headache, dizziness, vision changes;
  • tremors or shaking, feeling anxious or nervous;
  • pain, weakness, yawning, tired feeling;
  • upset stomach, loss of appetite, nausea, vomiting, diarrhea;
  • dry mouth, sweating, hot flashes;
  • changes in weight or appetite;
  • stuffy nose, sinus pain, sore throat, flu symptoms; or
  • decreased sex drive, impotence, or difficulty having an orgasm.

Interactions

Taking fluoxetine with other drugs that make you sleepy or slow your breathing can cause dangerous side effects or death. Ask your doctor before taking a sleeping pill, narcotic pain medicine, prescription cough medicine, a muscle relaxer, or medicine for anxiety, depression, or seizures.

Many drugs can interact with fluoxetine. Not all possible interactions are listed here. Tell your doctor about all your current medicines and any you start or stop using, especially:

  • any other antidepressant;
  • St. John’s Wort;
  • tryptophan (sometimes called L-tryptophan);
  • a blood thinner – warfarin, Coumadin, Jantoven;
  • medicine to treat anxiety, mood disorders, thought disorders, or mental illness – amitriptyline, buspirone, desipramine, lithium, nortriptyline, and many others;
  • medicine to treat ADHD or narcolepsy – Adderall, Concerta, Ritalin, Vyvanse, Zenzedi, and others;
  • over-the-counter pain medications including ibuprofen, acetaminophen, aspirin, or similar medications;
  • migraine headache medicine – rizatriptan, sumatriptan, zolmitriptan, and others;
  • narcotic pain medicine – fentanyl, tramadol.

Always consult your healthcare provider to ensure the information displayed on this page applies to your personal circumstances.

Keywords: fluoxetine; SSRI; antidepressants.

* The Content is not intended to be a substitute for professional medical advice, diagnosis, or treatment. Always seek the advice of your physician or other qualified health provider with any questions you may have regarding a medical condition.