Quetiapine ER (Seroquel XR)

FDA Approved 2007

Reviewed by the HeyPsych Medical Review Board

Board-certified psychiatrists and mental health professionals

Indications

Primary Indications

Treatment of schizophrenia in adults and adolescentsTreatment of acute manic or mixed episodes associated with bipolar I disorderTreatment of bipolar depressionAdjunctive therapy in major depressive disorder

Mechanism

Quetiapine acts as an antagonist at dopamine D2 and serotonin 5-HT2A receptors, contributing to its antipsychotic and mood-stabilizing effects. It also has antagonistic activity at histamine H1 and alpha-1 adrenergic receptors, leading to sedative and hypotensive effects.

Dosing

Adult Dosing

Schizophrenia: 300–800 mg once daily, starting at 300 mg and titrating as tolerated

Bipolar mania: 400–800 mg once daily, titrated over several days

Bipolar depression: 300 mg once daily at bedtime

MDD adjunct: 150–300 mg once daily in the evening

Dosage Forms

Extended-release tablets: 50 mg, 150 mg, 200 mg, 300 mg, 400 mg

Onset Duration

Onset: Within several days for mood symptoms, 1–2 weeks for antipsychotic effects; Duration: 24 hours with XR formulation

Adverse Effects

Common Side Effects

• somnolence

• dizziness

• dry mouth

• constipation

• weight gain

⚠️ Serious Side Effects

neuroleptic malignant syndrome
tardive dyskinesia
severe metabolic effects
QT prolongation

Warnings

Critical Safety Information

→Elderly patients with dementia-related psychosis have an increased risk of death
→Monitor metabolic parameters regularly
→Use caution in patients with cardiovascular disease

Interactions

With: CYP3A4 inhibitors (e.g., ketoconazole)

Risk: Increased quetiapine levels

Action: Avoid or reduce dose

With: CYP3A4 inducers (e.g., phenytoin, rifampin)

Risk: Reduced quetiapine levels

Action: May require dose increase

With: CNS depressants

Risk: Additive sedation

Action: Use with caution

Monitoring

Metabolic parameters
Cardiac status (QT interval)
Ophthalmologic exams periodically for cataract risk

Special Populations

👶Pregnancy

Category C; use only if potential benefit justifies potential risk

🤱Breastfeeding

Excreted in breast milk; caution advised

👴Older Adults (65+)

Increased risk of hypotension and sedation; use lower starting doses

Tapering

Gradual dose reduction over at least 1–2 weeks to minimize withdrawal symptoms such as insomnia, nausea, and return of psychotic or mood symptoms

Clinical Notes

XR formulation should be taken without food or with a light meal (≤300 calories) to avoid altered absorption
Sedation can be beneficial for patients with comorbid insomnia
May cause dose-related orthostatic hypotension—advise slow position changes

This medication information is for educational purposes only and is not a substitute for professional medical advice. Always consult your healthcare provider before starting, stopping, or changing any medication. Never take medication without a prescription from a licensed healthcare provider.

Interested in this treatment?

This information is for educational purposes. Always consult with a qualified healthcare provider before starting any new treatment.

Locate Psychiatrists