Seroquel was already approved to treat the manic phases of bipolar disorder(formerly called manic-depressive illness). It had also been approved for the treatment of schizophrenia.
The FDA's action makes Seroquel the first drug to treat both the depressive and manic phases of bipolar disorder, says Seroquel's maker, AstraZeneca, in a news release.
The FDA decision was based on an eight-week study of 1,045 patients with bipolar depression, the drug company tells WebMD.
Patients were randomly assigned to take Seroquel or a placebo containing no medicine.
Those taking Seroquel showed greater improvement in bipolar depression symptoms, overall quality of life, and satisfaction related to functioning, says AstraZeneca.
The studies tested two doses of Seroquel: 300 milligrams and 600 milligrams per day.
The higher dose showed no added benefits, so the 300 milligram daily dose is what's recommended, says AstraZeneca.
Seroquel was generally well tolerated in the studies, according to the drug company. The most common side effects were dry mouth, sedation, sleepiness, dizziness, and constipation.
The drug is not approved for use in children. Check the labeling for Seroquel's warnings.