Quetiapine fumarate. Molecular model of the drug quetiapine fumarate (C42.H50.N6.O4.S2?C4.H4.O4). This atypical antipsychotic drug is sold under the brand name Seroquel. It is used for treatment of schizophrenia, bipolar disorder, and along with an antidepressant to treat major depressive disorder. Atoms are represented as spheres and are colour-coded: carbon (grey), hydrogen (white), nitrogen (blue), oxygen (red) and sulfur (yellow).