Prozac (Fluoxetine) Patient Information
Find out why Prozac is prescribed, side effects of Prozac, Prozac warnings, effects of Prozac during pregnancy, more - in plain English.
Generic name: Fluoxetine hydrochloride
Brand names: Prozac, Sarafem
Why is Prozac prescribed?
Prozac is prescribed for the treatment of depression--that is, a continuing depression that interferes with daily functioning. The symptoms of major depression often include changes in appetite, sleep habits, and mind/body coordination; decreased sex drive; increased fatigue; feelings of guilt or worthlessness; difficulty concentrating; slowed thinking; and suicidal thoughts.
Prozac is also prescribed to treat obsessive-compulsive disorder. An obsession is a thought that won't go away; a compulsion is an action done over and over to relieve anxiety. The drug is also used in the treatment of bulimia (binge-eating followed by deliberate vomiting). It has also been used to treat other eating disorders and obesity.
In addition, Prozac is used to treat panic disorder, including panic associated with agoraphobia (a severe fear of being in crowds or public places). People with panic disorder usually suffer from panic attacks--feelings of intense fear that develop suddenly, often for no reason. Various symptoms occur during the attacks, including a rapid or pounding heartbeat, chest pain, sweating, trembling, and shortness of breath.
In children and adolescents, Prozac is used to treat major depression and obsessive-compulsive disorder.
Under the brand name Sarafem, the active ingredient in Prozac is also prescribed for the treatment of premenstrual dysphoric disorder (PMDD), formerly known as premenstrual syndrome (PMS). Symptoms of PMDD include mood problems such as anxiety, depression, irritability or persistent anger, mood swings, and tension. Physical problems that accompany PMDD include bloating, breast tenderness, headache, and joint and muscle pain. Symptoms typically begin 1 to 2 weeks before a woman's menstrual period and are severe enough to interfere with day-to-day activities and relationships.
Prozac is a member of the family of drugs called "selective serotonin re-uptake inhibitors." Serotonin is one of the chemical messengers believed to govern moods. Ordinarily, it is quickly reabsorbed after its release at the junctures between nerves. Re-uptake inhibitors such as Prozac slow this process, thereby boosting the levels of serotonin available in the brain.
Most important fact about Prozac
Most important fact about this drug
Serious, sometimes fatal, reactions have been known to occur when Prozac is used in combination with other antidepressant drugs known as MAO inhibitors, including Nardil and Parnate; and when Prozac is discontinued and an MAO inhibitor is started. Never take Prozac with one of these drugs or within at least 14 days of discontinuing therapy with one of them; and allow 5 weeks or more between stopping Prozac and starting an MAO inhibitor. Be especially cautious if you have been taking Prozac in high doses or for a long time.
If you are taking any prescription or nonprescription drugs, notify your doctor before taking Prozac.
How should you take Prozac?
How should you take this medication?
Prozac should be taken exactly as prescribed by your doctor.
Prozac usually is taken once or twice a day. To be effective, it should be taken regularly. Make a habit of taking it at the same time you do some other daily activity.
It may be 4 weeks before you feel any relief from your depression, but the drug's effects should last about 9 months after a 3-month treatment regimen. For obsessive-compulsive disorder, the full effect may take 5 weeks to appear.
--If you miss a dose...
Take the forgotten dose as soon as you remember. If several hours have passed, skip the dose. Never try to "catch up" by doubling the dose.
Store at room temperature.
What side effects may occur when taking Prozac?
What side effects may occur?
Side effects cannot be anticipated. If any develop or change in intensity, inform your doctor as soon as possible. Only your doctor can determine if it is safe for you to continue taking Prozac.
More common side effects of Prozac may include: Abnormal dreams, abnormal ejaculation, abnormal vision, anxiety, diminished sex drive, dizziness, dry mouth, flu-like symptoms, flushing, gas, headache, impotence, insomnia, itching, loss of appetite, nausea, nervousness, rash, sinusitis, sleepiness, sore throat, sweating, tremors, upset stomach, vomiting, weakness, yawning
Less common side effects may include: Abnormal taste, agitation, bleeding problems, chills, confusion, ear pain, emotional instability, fever, frequent urination, high blood pressure, increased appetite, loss of memory, palpitations, ringing in the ears, sleep disorders, weight gain
In children and adolescents, less common side effects may also include: Agitation, excessive menstrual bleeding, frequent urination, hyperactivity, mania or hypomania (inappropriate feelings of elation and/or rapid thoughts), nosebleeds, personality changes, and thirst A wide variety of other very rare reactions have been reported during Prozac therapy. If you develop any new or unexplained symptoms, tell your doctor without delay.
Why should this drug not be prescribed?
Why should this drug not be prescribed?
If you are sensitive to or have ever had an allergic reaction to Prozac or similar drugs such as Paxil and Zoloft, you should not take this medication. Make sure that your doctor is aware of any drug reactions that you have experienced.
Do not take this drug while using an MAO inhibitor. (See "Most important fact about this drug.") You should also not use Prozac if you are taking Mellaril (thioridazine). Likewise, do not start taking Mellaril within 5 weeks of stopping Prozac.
Special warnings about Prozac
Special warnings about this medication
Unless you are directed to do so by your doctor, do not take this medication if you are recovering from a heart attack or if you have liver disease or diabetes.
Prozac may cause you to become drowsy or less alert and may affect your judgment. Therefore, driving or operating dangerous machinery or participating in any hazardous activity that requires full mental alertness is not recommended.
While taking this medication, you may feel dizzy or light-headed or actually faint when getting up from a lying or sitting position. If getting up slowly doesn't help or if this problem continues, notify your doctor.
If you develop a skin rash or hives while taking Prozac, discontinue use of the medication and notify your doctor immediately.
Prozac should be used with caution if you have a history of seizures. You should discuss all of your medical conditions with your doctor before taking this medication.
Prozac can occasionally cause decreased appetite and weight loss, especially in depressed people who are already underweight and in those with bulimia. If you notice changes in your weight or appetite, tell your doctor.
Possible food and drug interactions when taking Prozac
Possible food and drug interactions when taking this medication
Combining Prozac with MAO inhibitors or Mellaril (thioridazine) is dangerous.
Do not drink alcohol while taking this medication.
If Prozac is taken with certain other drugs, the effects of either could be increased, decreased, or altered. It is especially important to check with your doctor before combining Prozac with the following:
Drugs that impair brain function, such as sleep aids and narcotic painkillers
Other antidepressants (Elavil)
Special information if you are pregnant or breastfeeding
Special information if you are pregnant or breastfeeding
The effects of Prozac during pregnancy have not been adequately studied. If you are pregnant or plan to become pregnant, inform your doctor immediately. This medication appears in breast milk, and breastfeeding is not recommended while you are taking Prozac.
Recommended dosage for Prozac
The usual starting dose is 20 milligrams per day, taken in the morning. Your doctor may increase your dose after several weeks if no improvement is observed. People with kidney or liver disease, the elderly, and those taking other drugs may have their dosages adjusted by their doctor. Dosages above 20 milligrams daily should be taken once a day in the morning or in 2 smaller doses taken in the morning and at noon.
The usual daily dose for depression ranges from 20 to 60 milligrams. For obsessive-compulsive disorder the customary range is 20 to 60 milligrams per day, though a maximum of 80 milligrams is sometimes prescribed. For bulimia nervosa, the usual dose is 60 milligrams, taken in the morning. Your doctor may have you start with less and build up to this dosage. The usual dose for premenstrual dysphoric disorder is 20 milligrams a day.
For depression, it may take up to 4 weeks before the full effects of the medication are seen. For obsessive-compulsive disorder, treatment can take 5 weeks or more to be effective.
If you are taking a 20-milligram daily dose of Prozac for depression, the doctor may switch you to a delayed-release formulation called Prozac Weekly. To make the change, you'll be asked to skip your daily dose for 7 days, then take your first weekly capsule.
The usual starting dose for depression is 10 or 20 milligrams a day. After 1 week at 10 milligrams a day, the doctor may increase the dose to 20 milligrams. It may take up to 4 weeks before the full effects of the medication are seen. For obsessive-compulsive disorder, the usual starting dose is 10 milligrams a day. After 2 weeks, the doctor may increase the dose to 20 milligrams. If no improvement is seen after several weeks, the dosage may be increased as needed, up to a maximum of 60 milligrams a day. Treatment may take 5 weeks or more to be effective.
Children who are underweight, have kidney or liver problems, or are taking multiple medications may need their dosages adjusted by their doctor.
Any medication taken in excess can have serious consequences. An overdose of Prozac can be fatal. In addition, combining Prozac with certain other drugs can cause symptoms of overdose. If you suspect an overdose, seek medical attention immediately.
Common symptoms of Prozac overdose include: Nausea, rapid heartbeat, seizures, sleepiness, vomiting
Other symptoms of Prozac overdose include: Coma, delirium, fainting, high fever, irregular heartbeat, low blood pressure, mania, rigid muscles, sweating, stupor
Last Updated: 09 April 2017
Reviewed by Harry Croft, MD