Renapine XR 300 mg is an extended-release formulation of Quetiapine Fumarate, an atypical antipsychotic medication used to treat conditions like schizophrenia, bipolar disorder (manic and depressive episodes), and as an adjunct for major depressive disorder. The extended-release form ensures once-daily dosing, improving patient adherence. It works by modulating neurotransmitter activity in the brain, helping to stabilize mood and thought processes.