quetiapine, Seroquel, Seroquel XR (cont.)

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St. John's Wort, carbamazepine (Tegretol), and rifampin (Rifadin) will decrease the level or effect of quetiapine by increasing the breakdown of quetiapine.

PREGNANCY: There are no adequate studies of quetiapine in pregnant women. Studies in animals are inconsistent. Some studies suggest effects on the fetus and others show no effects. Quetiapine should be used in pregnancy only if the physician feels that it is necessary and that the potential benefits justify the unknown risks.

NURSING MOTHERS: Quetiapine is excreted in the milk of animals during lactation. Although it is not known if it is excreted in human milk, it is recommended that women taking quetiapine not breastfeed.

SIDE EFFECTS: Frequent adverse effects include headache, agitation, dizziness, drowsiness, weight gain and stomach upset. Quetiapine can cause orthostatic hypotension (a drop in blood pressure upon standing that can lead to dizziness or fainting) especially during the first 3-5 day period of treatment, when it is restarted after temporary discontinuation, and after an increase in the dose. The risk of orthostatic hypotension is about 1 in 100 (one of every hundred patients who take quetiapine). Quetiapine frequently causes tiredness (1 in 5 patients), especially during the first 3-5 days of treatment. Because of this tiredness, care should be exercised in any activity requiring mental alertness such as operating a motor vehicle or hazardous machinery. Less common side effects include seizures (1 in 125 patients) and hypothyroidism (1 in 250 patients).

As with other antipsychotics, long-term use of quetiapine may lead to irreversible tardive dyskinesia, a neurologic disease which consists of involuntary movements of the jaw, lips, and tongue.

A potentially fatal complex referred to as neuroleptic malignant syndrome (NMS) has been reported with antipsychotic drugs. Patients who develop NMS may have high fevers, muscle rigidity, altered mental status, irregular pulse or blood pressure, rapid heart rate, excessive sweating, and heart arrhythmias.

In animals, quetiapine has been associated with the development of cataracts, and cataracts have been reported in patients using quetiapine for prolonged periods. Although it is not clear if quetiapine was responsible for the cataracts seen in humans, eye examinations by slit-lamp (to identify cataracts before they impair vision) are recommended at the beginning of treatment and every six months during treatment. If cataracts form, treatment should be discontinued. Quetiapine may increase blood concentrations of cholesterol and triglycerides by 11% and 17%, respectively.

There is an increased risk of hyperglycemia (high blood glucose) and diabetes-related events in patients taking atypical antipsychotics, including quetiapine. Patients should be tested during treatment for elevated blood-sugars. Additionally, persons with risk factors for diabetes, including obesity or a family history of diabetes, should have their fasting levels of blood sugar tested before starting treatment and periodically throughout treatment to detect the onset of diabetes. Any patient developing symptoms that suggest diabetes during treatment should be tested for diabetes.

Elderly patients with dementia-related psychosis treated with antipsychotics are at an increased risk of death. There is an increased risk of suicidal thinking and behavior in children, adolescents and young adults taking antidepressants for major depression and other psychiatric disorders.

Reference: FDA Prescribing Information


Last Editorial Review: 4/1/2013



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