Antidepressants increase risk of suicidal thinking and behavior in children, adolescents, and young adults (18-24 years of age) with major depressive disorder and other psychiatric disorders (quetiapine not FDA approved for use in children). May worsen psychosis in some patients or precipitate shift to mania or hypomania in bipolar disorder. Quetiapine is FDA approved for treatment of bipolar depression. Use may be associated with neuroleptic malignant syndrome. May be sedating (caution in disorders with CNS depression). May cause extrapyramidal symptoms, including pseudoparkinsonism, acute dystonic reactions, akathisia, and tardive dyskinesia. Risk of dystonia may be greater with increased doses, use of conventional antipsychotics, males, and younger patients. May alter cardiac conduction (life-threatening arrhythmias occurred). May cause orthostatic hypotension. Use with caution in severe cardiac disease, hemodynamic instability, prior myocardial infarction, ischemic heart disease, or hypercholesterolemia. May cause anticholinergic effects (caution in decreased gastrointestinal motility, urinary retention, BPH, xerostomia, or visual problems). Leukopenia, neutropenia, and agranulocytosis (sometimes fatal) reported. Cataracts described in animals. Use with caution in narrow-angle glaucoma (higher risk by cholinergic blockade). Antipsychotic use associated with esophageal dysmotility and aspiration (use with caution in risk of pneumonia (e.g. Alzheimer’s disease)). Atypical antipsychotics associated with development of hyperglycemia; in some cases, may be extreme and associated with ketoacidosis, hyperosmolar coma, or death (caution in diabetes or other glucose regulation disorders). Increases in cholesterol and triglycerides noted. Use with caution in pre-existing abnormal lipid profile. Significant weight gain observed with antipsychotic therapy (incidence varies with product). Impaired core body temperature regulation may occur. Elderly patients with dementia-related psychosis treated with antipsychotic drugs are at increased risk of death compared to placebo. Increased incidence of cerebrovascular adverse events (including fatalities) reported in elderly patients with dementia-related psychosis (quetiapine not approved for this indication). Use with caution in hepatic disease or impairment; may increase transaminases (primarily ALT). Substantial hepatic metabolism via CYP3A4. Use with caution in renal disease, in myasthenia gravis (may be exacerbated by cholinergic blockade), in Parkinson’s disease, and in patients at risk of seizures, including those with history of seizures, head trauma, brain damage, alcoholism, or concurrent therapy with medications which may lower seizure threshold. Elderly patients may be at increased risk of seizures due to increased prevalence of predisposing factors. Use with caution in thyroid disease. May mask toxicity of other drugs due to antiemetic effects. Use caution when withdrawing therapy (acute withdrawal symptoms may occur).