In the U.S.—

• Antipsychotic

Quetiapine (kwe-TYE-a-peen ) is used to treat psychotic disorders, such as schizophrenia.

Quetiapine is available only with your doctor's prescription, in the following dosage form:

Oral
• Tablets (U.S. and Canada)

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 quetiapine, the following should be considered:

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

Pregnancy—Quetiapine has not been studied in pregnant women. However, studies in rats and rabbits have shown that quetiapine at doses higher than the highest human dose causes reduced weight and other problems in the fetus. Before taking this medicine, make sure your doctor knows if you are pregnant or if you may become pregnant.

Breast-feeding—Quetiapine has been shown to pass into the milk of animals. It is not known whether this medicine passes into breast milk. However, quetiapine is not recommended for use during breast-feeding, because it may cause unwanted effects in nursing babies. Be sure you have discussed the risks and benefits of the medicine with your doctor.

Children—Studies on this medicine have been done only in adult patients, and there is no specific information comparing use of quetiapine in children with use in other age groups.

Older adults—This medicine has been tested in a limited number of patients 65 years of age or older and has not been shown to cause different side effects or problems in older people than it does in younger adults. However, quetiapine may be removed from the body more slowly in older adults, so an older adult may receive a lower dose than a younger adult.

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 quetiapine, it is especially important that your health care professional know if you are taking any of the following:

• Alcohol (with chronic use) or
• Barbiturates or
• Carbamazepine (e.g., Tegretol) or
• Griseofulvin (e.g., Fulvicin) or
• Phenylbutazone (e.g., Butazolidin) or
• Phenytoin (e.g., Dilantin) or
• Primidone (e.g., Mysoline) or
• Rifampin (e.g., Rifadin) or
• Saquinavir (e.g., Invirase) or
• Troglitazone (e.g., Rezulin)—These medicines may cause lower blood levels of quetiapine; the dose of quetiapine may need to be changed if one of these medicines is started or stopped during treatment with quetiapine

• Central nervous system (CNS) depressants (medicines that cause drowsiness) or
• Tricyclic antidepressants (medicine for depression)—Quetiapine may increase the CNS depressant effects of these medicines, such as drowsiness

• Clarithromycin (e.g., Biaxin) or
• Diltiazem (e.g., Cardizem) or
• Erythromycin (e.g., E-Mycin, E.E.S.) or
• Fluconazole (e.g., Diflucan) or
• Itraconazole (e.g., Sporanox) or
• Ketoconazole (e.g., Nizoral) or
• Nefazodone (e.g., Serzone) or
• Verapamil (e.g., Calan)—These medicines may cause higher blood levels of quetiapine, increasing the chance of side effects

• Alzheimer's disease—Quetiapine may cause problems with swallowing, which may increase the chance of pneumonia; also, the chance of seizures may be increased

• Breast cancer, or history of or
• Underactive thyroid—Quetiapine may make these conditions worse

• Dehydration—Decreased blood pressure caused by quetiapine may be more severe; chance of developing heatstroke may be increased

• Heart disease or
• Stroke, or history of—Decreased blood pressure caused by quetiapine may be more severe or may make these conditions worse

• Kidney disease (severe) or
• Liver disease—Higher blood levels of quetiapine may occur, increasing the chance of side effects; the dose may need to be changed

• Seizures, or history of—Chance of seizures may be increased

Take this medicine only as directed by your doctor to benefit your condition as much as possible. Do not take more or less of it and do not take it more or less often than your doctor ordered.

Quetiapine may be taken with or without food on a full or empty stomach. However, if your doctor tells you to take it a certain way, take it as directed.

Dosing—

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

The number of tablets 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 quetiapine.

• For oral dosage form (tablets):
  • For schizophrenia:
    • Adults—At first, 25 milligrams (mg) two times a day. The dose usually is increased to 300 to 400 mg a day, which is divided and given in two or three doses a day. Your doctor may increase your dose further, if needed. However, the dose usually is not more than 800 mg a day.
    • Children—Use and dose must be determined by the doctor.

Missed dose—

If you miss a dose of quetiapine, take it as soon as possible. However, if it is almost time for your next dose, skip the missed dose and go back to your regular dosing schedule. Do not double doses.

Storage—

To store this medicine:

• Keep out of the reach of children.
• Store away from heat and direct light.
• 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.

Your doctor should check your progress at regular visits, especially during the first few months of treatment with this medicine. This will allow your dosage to be changed if necessary to meet your needs.

This medicine may add to the effects of alcohol and other CNS depressants (medicines that make you drowsy or less alert). Some examples of CNS depressants are antihistamines or medicine for hay fever, other allergies, or colds; sedatives, tranquilizers, or sleeping medicine; prescription pain medicine or narcotics; barbiturates; medicine for seizures; muscle relaxants; or anesthetics, including some dental anesthetics. Check with your doctor before taking any of the above while you are using quetiapine.

Quetiapine may cause drowsiness, especially during the first week of use. Make sure you know how you react to this medicine before you drive, use machines, or do anything else that could be dangerous if you are not alert.

Dizziness, lightheadedness, or fainting may occur, especially when you get up from a lying or sitting position. Getting up slowly may help. If the problem continues or gets worse, check with your doctor.

Quetiapine may make it more difficult for your body to cool down. Use extra care not to become overheated and to drink plenty of fluids during exercise or hot weather while you are taking this medicine . Overheating may result in heatstroke.

Along with its needed effects, quetiapine can sometimes cause serious side effects. Some side effects will have signs or symptoms that you can see or feel. Your doctor may watch for others, such as changes in the lenses of the eyes, by doing certain tests. Tardive dyskinesia (a movement disorder) may occur and may not go away after you stop using the medicine. Signs of tardive dyskinesia include fine, worm-like movements of the tongue, or other uncontrolled movements of the mouth, tongue, cheeks, jaw, or arms and legs. Another serious but rare side effect that may occur is the neuroleptic malignant syndrome (NMS). You and your doctor should discuss the good this medicine will do as well as the risks of taking it.

Stop taking this medicine and get emergency help immediately if the following side effects occur:

• Rare--Symptoms of NMS; two or more occur together; most of these effects do not require emergency medical attention if they occur alone
  • Convulsions (seizures);  difficult or unusually fast breathing;  fast heartbeat or irregular pulse;  high fever;  high or low (irregular) blood pressure;  increased sweating;  loss of bladder control;  severe muscle stiffness;  unusually pale skin;  unusual tiredness or weakness 
  
  

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

• Less common
  • Dizziness, lightheadedness, or fainting, especially when getting up from a lying or sitting position;  fever, chills, muscle aches, or sore throat;  loss of balance control ;  mask-like face;  shuffling walk;  skin rash;  slowed movements;  stiffness of arms or legs;  swelling of feet or lower legs;  trembling and shaking of hands and fingers;  trouble in breathing, speaking, or swallowing 
  
  

• Rare
  • Fainting;  fast, pounding, or irregular heartbeat;  menstrual changes;  unusual secretion of milk (in females) 
  
  

• Rare--Symptoms of underactive thyroid; usually two or more occur together; these effects do not require medical attention if they occur alone unless they continue or are bothersome
  • Dry, puffy skin;  loss of appetite;  tiredness;  weight gain 
  
  

• Symptoms of overdose--May be similar to side effects seen at normal doses but may be more severe or two or more may occur together
  • Drowsiness;  fast, slow, or irregular heartbeat;  low blood pressure;  weakness 
  
  

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
  • Constipation;  drowsiness;  dry mouth;  increased weight;  indigestion 
  
  

• Less common
  • Abdominal pain;  abnormal vision;  decrease in appetite;  decreased strength and energy;  feeling of fast or irregular heartbeat ;  headache;  increased muscle tone;  increased sweating;  stuffy or runny nose 
  
  

Other side effects not listed above may also occur in some patients. If you notice any other effects, check with your doctor.