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 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

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

• 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