Seroquel XR

Generic name:

Quetiapine fumarate extended-release

Drug class:

Atypical antipsychotic (second-generation antipsychotic)

Dosage form:

Extended-release tablets (50 mg, 150 mg, 200 mg, 300 mg, 400 mg)

Root of administration:

Oral

Dose:

Schizophrenia (adults): initiate 300 mg once daily, titrate to 400–800 mg; Bipolar mania/mixed episodes: start 300 mg once daily, titrate to 300–800 mg; Bipolar depression: up to 300 mg once daily; Adjunctive in major depressive disorder: 50–300 mg once daily; Geriatric patients: initiate at 50 mg, titrate slowly; Varies by indication; consult label for detailed dosing.

Mechanism of action:

Quetiapine XR antagonizes serotonin 5-HT_2A, dopamine D₂, histamine H₁, and adrenergic α₁/α₂ receptors, with higher affinity for 5-HT_2A than D₂, modulating neurotransmitter activity to alleviate psychotic symptoms and stabilize mood.

Drug usage cases:

• Schizophrenia in adults
• Bipolar disorder: manic and mixed episodes
• Bipolar depression
• Major depressive disorder (adjunctive therapy)
• Generalized anxiety disorder (off-label)
• Post-traumatic stress disorder (off-label)
• Insomnia (off-label, low dose)

Drug contra indications:

• Hypersensitivity to quetiapine or its components
• Concomitant use with strong CYP3A4 inhibitors (e.g., ketoconazole)
• History of severe cardiac arrhythmias or QT prolongation
• Neuroleptic malignant syndrome
• Severe CNS depression or comatose state
• Breastfeeding (absolute contraindication)

Side effects:

• Somnolence
• Dizziness
• Dry mouth
• Constipation
• Orthostatic hypotension
• Weight gain
• Metabolic changes (hyperglycemia, dyslipidemia)
• Headache
• Fatigue
• Blurred vision
• Elevated liver enzymes
• Extrapyramidal symptoms (rare)
• Akathisia
• Tardive dyskinesia
• Seizures (dose-related risk)
• QT prolongation
• Thrombocytopenia and other blood dyscrasias (rare)
• Neuroleptic malignant syndrome

Warnings:

• Elderly patients with dementia-related psychosis increased risk of death
• Risk of suicidal thoughts and behaviors in young patients
• Orthostatic hypotension and syncope, especially during dose titration
• Metabolic syndrome: monitor weight, blood glucose, lipids
• QT interval prolongation: caution with other QT-prolonging agents
• Neuroleptic malignant syndrome: discontinue if suspected
• Drug interactions with CYP3A4 inhibitors/inducers
• Potential withdrawal symptoms: taper gradually
• Ophthalmic monitoring for cataracts recommended
• Sleep-related behaviors (e.g., somnambulism, driving) reported

Use during pregnancy or breastfeeding:

Pregnancy: Category C. Animal studies indicate fetal risk; prescribe only if benefits justify potential risks. Monitor neonates for extrapyramidal or withdrawal symptoms. Breastfeeding: Quetiapine is excreted in breast milk; potential sedation and adverse effects in the infant; advise against breastfeeding or discontinue therapy.