Detailed dosage guidelines and administration information for Seroquel (quetiapine fumarate). Includes dose adjustments, warnings and precautions. Quetiapine (Seroquel) is an antipsychotic that treats schizophrenia and bipolar disorder. It balances dopamine and serotonin in your brain. Seroquel is a prescription tablet used to treat bipolar I disorder and certain other mental health conditions. Learn about its dosage, side effects, and more. Quetiapine is one of only two antipsychotics (the other is cariprazine) that produce equal efficacy as standalone therapies for mixed manic-depressive mood swings as they do in combination with an SSRI antidepressant. Quetiapine is used alone or together with other medicines to treat bipolar disorder (depressive and manic episodes) and schizophrenia. Quetiapine extended-release tablet is also used together with other antidepressants to treat major depressive disorder. Seroquel is used to treat the symptoms of schizophrenia, bipolar disorder and major depressive disorder. Learn about side effects, interactions and indications. Find patient medical information for Quetiapine (Seroquel) on WebMD including its uses, side effects and safety, interactions, pictures, warnings, and user ratings SEROQUEL XR is a once-daily tablet approved in adults for add-on treatment to antidepressants for patients with major depressive disorder (MDD) who did not have an adequate response to antidepressant therapy; Seroquel is a prescription medicine used to treat the symptoms of Schizophrenia, Bipolar I Disorder, Mania; Bipolar Disorder, Depressive Episodes; Bipolar I Disorder, Maintenance; and Major Depressive Disorder. Seroquel may be used alone or with other medications. Seroquel (quetiapine) belongs to the atypical (second-generation) antipsychotic class. These medications are used for schizophrenia and bipolar disorder and as an add-on for treatment-resistant depression, and they work differently from antidepressants like SSRIs and SNRIs.