Quetiapine fumarate(Seroquel or Quetiapina) is an atypical antipsychotic used in the treatment of schizophrenia,bipolar I mania, bipolar II depression,bipolar I depression, and used off-label for a variety of other purposes,including insomnia and anxiety disorders.This means Quetiapine is dopamine,serotonin and adrenergic antagonist, anticholinergic substance and antihistamine.

Quetiapine Fumarate was absorbed well and metabolized completely after oral administration. The main metabolites in human plasma have no obvious pharmacological activity. Feeding had no significant effect on the bioavailability of quetiapine. The elimination half-life of quetiapine is about 7 hours. 83% of quetiapine binds to plasma proteins. Clinical trials confirm that quetiapine is effective when given twice a day. Positron emission tomography (PET) data further confirmed that the drug's occupation of 5HT2 and D2 receptors lasted 12 hours after administration.
Quetiapine Fumarate is primarily used to treat schizophrenia or bipolar disorder.
Schizophrenia
A Cochrane review comparing quetiapine to typical antipsychotics concluded that quetiapine.
Bipolar disorder
In those with bipolar disorder, quetiapine is used to treat depressive episodes, acute manic episodes associated with bipolar I disorder (as either monotherapy or adjunct therapy to lithium, valproate or lamotrigine), and maintenance treatment of bipolar I disorder (as adjunct therapy to lithium or divalproex)
Major depressive disorder
Quetiapine is effective when used by itself and when used along with other medications in major depressive disorder (MDD). However, sedation is often an undesirable side effect.
In the United States, the United Kingdom and Australia (while not subsidised by the Australian Pharmaceutical Benefits Scheme for treatment of MDD), quetiapine is licensed for use as an add on treatment in MDD.
Alzheimer's disease
Quetiapine does not decrease agitation among people with Alzheimer's. Quetiapine worsens intellectual functioning in the elderly with dementia and therefore is not recommended.