Health Library

Fluoxetine (By mouth)

Fluoxetine (floo-OX-e-teen)

Treats depression, obsessive-compulsive disorder (OCD), bulimia nervosa, and panic disorder. This medicine is an SSRI.

Brand Name(s):

PROzac

When This Medicine Should Not Be Used:

How to Use This Medicine:

Capsule, Delayed Release Capsule, Liquid, Tablet

• Take your medicine as directed. Your dose may need to be changed several times to find what works best for you. Take your medicine at the same time each day.
• You may need to take this medicine for a month or longer before you feel better. If you feel that the medicine is not working well, do not take more than your normal dose. Call your doctor for instructions.
• Measure the oral liquid medicine with a marked measuring spoon, oral syringe, or medicine cup.
• Delayed-release capsule: Swallow whole. Do not crush, break, or chew it.
• This medicine should come with a Medication Guide. Ask your pharmacist for a copy if you do not have one.
• Missed dose: Take a dose as soon as you remember. If it is almost time for your next dose, wait until then and take a regular dose. Do not take extra medicine to make up for a missed dose.
• Store the medicine in a closed container at room temperature, away from heat, moisture, and direct light.

Drugs and Foods to Avoid:

Ask your doctor or pharmacist before using any other medicine, including over-the-counter medicines, vitamins, and herbal products.

• Do not use this medicine together with pimozide or thioridazine. Do not use this medicine within 14 days of using an MAO inhibitor, and do not start an MAOI for at least 5 weeks after you stop using fluoxetine.
• Some medicines can affect how fluoxetine works. Tell your doctor if you are using any of the following:
  • Buspirone, carbamazepine, dolasetron, erythromycin, fentanyl, gatifloxacin, lithium, mefloquine, meperidine, methadone, moxifloxacin, pentamidine, phenytoin, probucol, St John's wort, tacrolimus, tramadol, vinblastine
  • Amphetamines
  • Blood thinner (including warfarin)
  • Diuretic (water pill)
  • Medicine for heart rhythm problems
  • Medicine to treat mental illness (including chlorpromazine, droperidol, iloperidone, ziprasidone)
  • NSAID pain or arthritis medicine (including aspirin, celecoxib, diclofenac, ibuprofen, naproxen)
  • Phenothiazine medicine
  • Triptan medicine to treat migraine headache
  • Tryptophan supplements
• Do not drink alcohol while you are using this medicine.
• Tell your doctor if you use anything else that makes you sleepy. Some examples are allergy medicine, narcotic pain medicine, and alcohol.

Warnings While Using This Medicine:

• Tell your doctor if you are pregnant or breastfeeding, or if you have kidney disease, liver disease, bleeding problems, diabetes, glaucoma, or a history of seizures. Tell your doctor if you have had heart disease, a heart rhythm problem (including QT prolongation), heart attack, heart failure, low blood pressure, or a stroke.
• For some children, teenagers, and young adults, this medicine may increase mental or emotional problems. This may lead to thoughts of suicide and violence. Talk with your doctor right away if you have any thoughts or behavior changes that concern you. Tell your doctor if you or anyone in your family has a history of bipolar disorder or suicide attempts.
• This medicine may cause the following problems:
  • Serotonin syndrome (may be life-threatening when used with certain other medicines)
  • Increased risk of bleeding problems
  • Heart rhythm problems, including QT prolongation
  • Sexual problems
• Do not stop using this medicine suddenly. Your doctor will need to slowly decrease your dose before you stop it completely.
• This medicine may make you dizzy or drowsy. Do not drive or do anything else that could be dangerous until you know how this medicine affects you.
• Your doctor will do lab tests at regular visits to check on the effects of this medicine. Keep all appointments.
• Keep all medicine out of the reach of children. Never share your medicine with anyone.

Possible Side Effects While Using This Medicine:

Call your doctor right away if you notice any of these side effects:

• Allergic reaction: Itching or hives, swelling in your face or hands, swelling or tingling in your mouth or throat, chest tightness, trouble breathing
• Anxiety, restlessness, fever, sweating, muscle spasms, nausea, vomiting, diarrhea, seeing or hearing things that are not there
• Changes in behavior, thoughts of hurting yourself or others
• Confusion, weakness, muscle twitching
• Eye pain, vision changes, seeing halos around lights
• Fast, pounding, or uneven heartbeat, dizziness
• Loss in sexual ability, desire, drive, or performance, delayed or inability to have an orgasm, inability to have or keep an erection
• Trouble keeping still, feeling restless and agitated, racing thoughts, excessive energy, trouble sleeping
• Unusual bleeding or bruising

If you notice these less serious side effects, talk with your doctor:

• Diarrhea, changes in appetite, weight gain or loss
• Drowsiness, sleepiness
• Dry mouth
• Lack or loss of strength

If you notice other side effects that you think are caused by this medicine, tell your doctor

Call your doctor for medical advice about side effects. You may report side effects to FDA at 1-800-FDA-1088

Last Updated: 9/6/2024