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treatment & management

Drug Profiles:
fluoxetine HCl

Prozac®

CAUTION: Federal law prohibits dispensing without prescription.

   
Description
Prozac® (fluoxetine HCl) is an antidepressant of the selective serotonin reuptake inhibitor (SSRI) family. These medicines are thought to work by increasing the activity of the chemical serotonin in the brain. It is used to treat mental depression. It is also used to treat obsessive-compulsive disorder, bulimia nervosa, and premenstrual dysphoric disorder. Prozac is also being prescribed by some doctors as Migraine preventive. In addition to use as a Migraine preventive, Migraineurs may find antidepressants useful for clinical (chemical) depression. Migraine and depression have a definite link — 47% of Migraineurs experience clinical depression as opposed to just 17% of the general population.

Oral

  • Capsules (U.S. and Canada)
  • Oral Solution (U.S. and Canada)
  • Tablets (U.S.)

Before Using This Medicine
In deciding to use a medicine, the risks of taking the medicine must be weighed against the good it will do. This is a decision you and your doctor will make. For fluoxetine, the following should be considered:

Allergies-
Tell your doctor if you have ever had any unusual or allergic reaction to fluoxetine. Also tell your health care professional if you are allergic to any other substances, such as foods, preservatives, or dyes.

Pregnancy-
One study of babies whose mothers had taken fluoxetine while they were pregnant found some problems in the babies, such as premature birth, jitteriness, and trouble in breathing or nursing. However, four other studies did not find any problems in babies or young children whose mothers had taken fluoxetine while they were pregnant. Tell your doctor if you are pregnant or if you may become pregnant while you are taking this medicine. FDA Pregnancy Category C.

Breast-feeding-
Fluoxetine passes into breast milk. A study of 11 breast-fed babies whose mothers were taking fluoxetine found no effect on the babies. However, another baby whose mother was taking this medicine had vomiting, watery stools, crying, and sleep problems. Be sure you have discussed the risks and benefits of this medicine with your doctor.

Children-
This medicine has been tested in a limited number of children 7 to 18 years of age. These studies indicate that fluoxetine may help to treat depression and obsessive-compulsive disorder in children. However, unusual excitement, restlessness, irritability, and trouble in sleeping may be especially likely to occur in children, who seem to be more sensitive than adults to the effects of fluoxetine. More study is needed to be sure fluoxetine is safe and effective in children.

Older adults-
Many medicines have not been tested in older people. Therefore, it may not be known whether they work exactly the same way they do in younger adults or if they cause different side effects or problems in older people. In studies done to date that included elderly people, fluoxetine did not cause different side effects or problems in older people than it did in younger adults.

Other medicines-
Although certain medicines should not be used together at all, in other cases two different medicines may be used together even if an interaction might occur. In these cases, your doctor may want to change the dose, or other precautions may be necessary. When you are taking fluoxetine, it is especially important that your health care professional know if you are taking any of the following:

  • Alprazolam (e.g., Xanax)—Higher blood levels of alprazolam may occur and its effects may be increased
  • Anticoagulants (blood thinners)
  • Digitalis glycosides (heart medicine)—Higher or lower blood levels of these medicines or fluoxetine may occur, increasing the chance of unwanted effects. Your doctor may need to see you more often, especially when you first start or when you stop taking fluoxetine. Your doctor also may need to change the dose of either medicine
  • Astemizole (e.g., Hismanal)—Higher blood levels of astemizole may occur, which increases the chance of having a very serious change in the rhythm of your heartbeat
  • Buspirone (e.g., BuSpar)
  • Bromocriptine (e.g., Parlodel)
  • Dextromethorphan (cough medicine)
  • Levodopa (e.g., Sinemet)
  • Lithium (e.g., Eskalith) or
  • Meperidine (e.g., Demerol)
  • Nefazodone (e.g., Serzone)
  • Pentazocine (e.g., Talwin)
  • Selective serotonin reuptake inhibitors, other (citalopram [Celexa], fluvoxamine [e.g., Luvox], paroxetine [e.g., Paxil], sertraline [e.g., Zoloft])
  • Street drugs (LSD, MDMA [e.g., ecstasy], marijuana) or
  • Sumatriptan (e.g., Imitrex)
  • Tramadol (e.g., Ultram)
  • Trazodone (e.g., Desyrel)
  • Tryptophan
  • Venlafaxine (e.g., Effexor)—Using these medicines with fluoxetine or within 5 weeks of stopping fluoxetine may increase the chance of developing a rare, but very serious, unwanted effect known as the serotonin syndrome. This syndrome may cause confusion, diarrhea, fever, poor coordination, restlessness, shivering, sweating, talking or acting with excitement you cannot control, trembling or shaking, or twitching. If you develop these symptoms contact your doctor as soon as possible. Taking tramadol with fluoxetine increases the chance of having convulsions (seizures). Also, taking tryptophan with fluoxetine may result in increased agitation or restlessness and intestinal or stomach problems
  • Moclobemide (e.g., Manerex)—The risk of developing serious unwanted effects, including the serotonin syndrome, is increased. Use of moclobemide with fluoxetine is not recommended. Also, it is recommended that 7 days be allowed between stopping treatment with moclobemide and starting treatment with fluoxetine, and it is recommended that 5 weeks be allowed between stopping treatment with fluoxetine and starting treatment with moclobemide
  • Monoamine oxidase (MAO) inhibitors (furazolidone [e.g., Furoxone], phenelzine [e.g., Nardil], procarbazine [e.g., Matulane], selegiline [e.g., Eldepryl], tranylcypromine [e.g., Parnate])— Do not take fluoxetine while you are taking or within 2 weeks of taking an MAO inhibitor. If you do, you may develop confusion, agitation, restlessness, stomach or intestinal problems, sudden high body temperature, extremely high blood pressure, and severe convulsions. At least 14 days should be allowed between stopping treatment with an MAO inhibitor and starting treatment with fluoxetine. If you have been taking fluoxetine, at least 5 weeks should be allowed between stopping treatment with fluoxetine and starting treatment with an MAO inhibitor
  • Phenytoin (e.g., Dilantin)
  • Tricyclic antidepressants (amitriptyline [e.g., Elavil], amoxapine [e.g., Asendin], clomipramine [e.g., Anafranil], desipramine [e.g., Pertofrane], doxepin [e.g., Sinequan], imipramine [e.g., Tofranil], nortriptyline [e.g., Aventyl], protriptyline [e.g., Vivactil], trimipramine [e.g., Surmontil])—Higher blood levels of these medicines may occur, which increases the chance of having serious side effects. Your doctor may want to see you more often and may need to change the doses of your medicines. Also, taking amitriptyline, clomipramine, or imipramine with fluoxetine may increase the chance of developing the serotonin syndrome

Other medical problems-
The presence of other medical problems may affect the use of fluoxetine. Make sure you tell your doctor if you have any other medical problems, especially:

  • Brain disease or mental retardation
  • Seizures, history of—The chance of having seizures may be increased
  • Diabetes—The amount of insulin or oral antidiabetic medicine that you need to take may change
  • Kidney disease
  • Liver disease—Higher blood levels of fluoxetine may occur, increasing the chance of side effects
  • Parkinson's disease—May become worse
  • Weight loss—Fluoxetine may cause weight loss. This weight loss is usually small, but if a large weight loss occurs, it may be harmful in some patients
     

Proper Use of This Medicine
It is important to use this medicine properly:

  • Take this medicine only as directed by your doctor
  • If this medicine upsets your stomach, it may be taken with food.
  • If you are taking fluoxetine for depression, it may take 4 weeks or longer before you begin to feel better. Also, you may need to keep taking this medicine for 6 months or longer to stop the depression from returningIf you are taking fluoxetine for obsessive-compulsive disorder, it may take 5 weeks or longer before you begin to get better. Your doctor should check your progress at regular visits during this time.
  • If you are taking fluoxetine for bulimia nervosa, you may begin to get better after 1 week.

Dosing-
The dose of fluoxetine will be different for different patients and for different medical problems. Follow your doctor's orders or the directions on the label. The following information includes only the average doses of fluoxetine. If your dose is different, do not change it unless your doctor tells you to do so:

The number of capsules or teaspoonfuls of solution that you take depends on the strength of the medicine. Also, the number of doses you take each day, the time allowed between doses, and the length of time you take the medicine depend on the medical problem for which you are taking fluoxetine.

For oral dosage forms (capsules or solution):

  • For depression or obsessive-compulsive disorder:
    • Adults—At first, usually 20 milligrams (mg) a day, taken as a single dose in the morning. Your doctor may increase the dose if needed. However, the dose usually is not more than 80 mg a day. Once your depression is under control, your doctor may wish to change you to a weekly dose. In this case, you will usually take a 90-mg capsule as a single dose one day per week.
    • Children—Use and dose must be determined by your doctor.
  • For bulimia nervosa:
    • Adults—Usually 60 milligrams (mg) a day, taken as a single dose in the morning. Your doctor may start with a lower dose and increase it gradually. The dose usually is not more than 80 mg a day.
    • Children—Use and dose must be determined by your doctor.
  • For premenstrual dysphoric disorder:
  • Adults—At first, usually 20 milligrams (mg) a day, taken as a single dose in the morning. Your doctor may increase the dose if needed. However, the dose usually is not more than 80 mg a day.
  • Children—Use and dose must be determined by your doctor.

Missed Dose-
If you miss a dose of this medicine, it is not necessary to make up the missed dose. Skip the missed dose and continue with your next scheduled dose. Do not double doses.

Storage-
To store this medicine:

  • Keep out of the reach of children.
  • Store away from heat and direct light.
  • Keep the oral solution form of this medicine from freezing.
  • Do not store in the bathroom, near the kitchen sink, or in other damp places. Heat or moisture may cause the medicine to break down.
  • Do not keep outdated medicine or medicine no longer needed. Be sure that any discarded medicine is out of the reach of children.

Precautions While Using This Medicine

  • It is important that your doctor check your progress at regular visits, to allow dosage adjustments and help reduce any side effects.
  • Do not take fluoxetine within 2 weeks of taking a monoamine oxidase (MAO) inhibitor (furazolidone, phenelzine, procarbazine, selegiline, or tranylcypromine) and do not take an MAO inhibitor for at least 5 weeks after taking fluoxetine
  • Avoid drinking alcohol while you are taking fluoxetine.
  • If you develop a skin rash or hives, stop taking fluoxetine and check with your doctor as soon as possible
  • For diabetic patients: This medicine may affect blood sugar levels. If you notice a change in the results of your blood or urine sugar tests or if you have any questions, check with your doctor.
  • This medicine may cause some people to become drowsy or less able to think clearly, or to have poor muscle control. Make sure you know how you react to fluoxetine before you drive, use machines, or do anything else that could be dangerous if you are not alert and well able to control your movements.

Side Effects of This Medicine
Along with its needed effects, a medicine may cause some unwanted effects. Although not all of these side effects may occur, if they do occur they may need medical attention.

Check with your doctor as soon as possible if any of the following side effects occur:

  • More common: Decreased sexual drive or ability; inability to sit still; restlessness; skin rash, hives, or itching
  • Less common: Chills or fever; joint or muscle pain
  • Rare: Breast enlargement or pain; convulsions (seizures); fast or irregular heartbeat; purple or red spots on skin; symptoms of hypoglycemia (low blood sugar), including anxiety or nervousness, chills, cold sweats, confusion, cool pale skin, difficulty in concentration, drowsiness, excessive hunger, fast heartbeat, headache, shakiness or unsteady walk, or unusual tiredness or weakness; symptoms of hyponatremia (low blood sodium), including confusion, convulsions (seizures), drowsiness, dryness of mouth, increased thirst, lack of energy; symptoms of serotonin syndrome, including diarrhea, fever, increased sweating, mood or behavior changes, overactive reflexes, racing heartbeat, restlessness, shivering or shaking; talking, feeling, and acting with excitement and activity you cannot control; trouble in breathing; unusual or incomplete body or facial movements; unusual secretion of milk, in females

Other side effects may occur that usually do not need medical attention. These side effects may go away during treatment as your body adjusts to the medicine. However, check with your doctor if any of the following side effects continue or are bothersome:

  • More common: Anxiety or nervousness; decreased appetite ; diarrhea; drowsiness; headache; increased sweating; nausea; tiredness or weakness; trembling or shaking; trouble in sleeping
  • Less common or rare: Abnormal dreams; change in sense of taste; changes in vision; chest pain; constipation; dizziness or lightheadedness; dryness of mouth; feeling of warmth or heat; flushing or redness of skin, especially on face and neck; frequent urination; hair loss; increased appetite; increased sensitivity of skin to sunlight; menstrual pain; stomach cramps, gas, or pain; vomiting; weight loss; yawning

After you stop taking fluoxetine, your body may need time to adjust. The length of time this takes depends on the amount of medicine you were using and how long you used it. During this period of time, check with your doctor if you notice any of the following side effects:

  • Anxiety; dizziness; feeling that body or surroundings are turning; general feeling of discomfort or illness; headache; nausea; sweating; unusual tiredness or weakness

Brand Names-

U.S.:

  • Prozac
  • Prozac Weekly
  • Sarafem

Canada:

  • Prozac
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Information offered at this Web site by either a lay person or a health professional should not be interpreted as giving a diagnosis or a treatment recommendation. These can only be provided by a physician who has had an opportunity to interact with a patient in person and at length, with access to the patient's previous records and appropriate follow-up.