quetiapine

Antipsychotic

Brands: SEROQUEL

Last reviewed 2025-09-23

Reviewed by PsychMed Editorial Team.

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Quick answers

What is quetiapine?
Quetiapine (Seroquel/Seroquel XR) is a second-generation antipsychotic approved for schizophrenia, bipolar I acute mania (monotherapy and adjunct), bipolar depression, and maintenance with lithium or divalproex, with both IR and XR tablets broadly available as generics.
What is SEROQUEL?
SEROQUEL is a brand name for quetiapine.
What is SEROQUEL (quetiapine) used for?
Label indications include: Schizophrenia; acute manic/mixed episodes; bipolar depression; adjunct for major depressive disorder.
What drug class is SEROQUEL (quetiapine)?
Antipsychotic.
What is the mechanism of action of SEROQUEL (quetiapine)?
Antagonist at 5‑HT2A and D2 (transient), strong H1 and alpha‑1 activity.
What strengths does SEROQUEL (quetiapine) come in?
Immediate-release tablets: 25, 50, 100, 200, 300, 400 mg; extended-release tablets: 50, 150, 200, 300, 400 mg.
Is SEROQUEL (quetiapine) a controlled substance?
No — it is not scheduled as a controlled substance under U.S. federal law.
What is SEROQUEL (quetiapine) dosing for schizophrenia?
Schizophrenia (IR): day 1 25 mg BID, titrate to 300–400 mg/day by day 4; maintenance 300–800 mg/day divided BID.
What is the maximum recommended dose of SEROQUEL (quetiapine)?
Maximum recommended dose for schizophrenia or mania is 800 mg/day; doses above this provide little added efficacy but increase metabolic and sedation burden.
What is the maximum dose of SEROQUEL (quetiapine) for major depressive disorder (clinical depression)?
Adjunct MDD: XR 150–300 mg nightly after gradual titration; reassess benefit within 4–8 weeks.

Snapshot

Class: Antipsychotic
Common US brands: SEROQUEL
Therapeutic drug monitoring not routinely recommended.
Last reviewed: 2025-09-23

Label indications

Schizophrenia; acute manic/mixed episodes; bipolar depression; adjunct for major depressive disorder.

View labelExact

Clinical Highlights

Quetiapine (Seroquel/Seroquel XR) is a second-generation antipsychotic approved for schizophrenia, bipolar I acute mania (monotherapy and adjunct), bipolar depression, and maintenance with lithium or divalproex, with both IR and XR tablets broadly available as generics. Quetiapine mechanism of action features low-affinity, rapid-dissociation D2 antagonism with potent 5-HT2A, H1, and α1 blockade—explaining its antidepressant utility, sedation, and orthostatic effects while keeping EPS risk low.

Clinicians favor quetiapine for its low EPS liability, antidepressant activity in bipolar disorder, and sedating properties, but metabolic burden, orthostatic hypotension, and potential misuse at low doses necessitate close monitoring.
CATIE data indicate comparable antipsychotic effectiveness but higher discontinuation for weight gain versus some peers—reinforce metabolic surveillance and lifestyle counselling.
The compare view can help contrast metabolic, prolactin, and sedation profiles, and the Quetiapine evidence feed can support adjusting regimens.
Schizophrenia (adults) (FDA 1997)
Schizophrenia (adolescents 13–17) (FDA 2006)
Bipolar I mania (adults) (FDA 2004)

Dosing & Formulations

Immediate-release tablets: 25, 50, 100, 200, 300, 400 mg; extended-release tablets: 50, 150, 200, 300, 400 mg. Schizophrenia (IR): day 1 25 mg BID, titrate to 300–400 mg/day by day 4; maintenance 300–800 mg/day divided BID.

Schizophrenia (XR): start 300 mg nightly, increase to 600 mg on day 2; adjust to 400–800 mg once nightly with consistent food timing.
Bipolar I acute mania: titrate to 400–800 mg/day by day 4 (IR divided or XR nightly); combination with lithium/divalproex improves response but heightens sedation.
Bipolar depression: XR 50 mg day 1, 100 mg day 2, 200 mg day 3, 300 mg nightly thereafter (150 mg for sensitive or older adults).
Adjunct MDD: XR 150–300 mg nightly after gradual titration; reassess benefit within 4–8 weeks.
Maximum recommended dose for schizophrenia or mania is 800 mg/day; doses above this provide little added efficacy but increase metabolic and sedation burden.

Monitoring & Risks

Boxed warning: Class boxed warning for increased mortality in elderly patients with dementia-related psychosis. Boxed warning: Suicidal thoughts and behaviors in children, adolescents, and young adults for the bipolar depression indication.

Sedation/somnolence: Dose-related; counsel on evening dosing and driving precautions.
Weight gain: ≥7% body weight increase in 15–23% over 6 months—monitor BMI and waist circumference.
Dizziness/orthostasis: Advise slow position changes during titration.
Dry mouth: Encourage hydration and oral hygiene.

Drug Interactions

Strong CYP3A4 inhibitors (e.g., ketoconazole, ritonavir) markedly increase exposure—avoid or reduce to ≤1/6th of the usual dose with intensive monitoring. Strong CYP3A4 inducers (e.g., carbamazepine, phenytoin, rifampin, St. John’s wort) sharply reduce levels—avoid or select an alternative antipsychotic.

Lithium or divalproex combinations increase sedation, tremor, and weight gain—monitor closely.
Additive hypotension occurs with antihypertensives and α1 blockers; check blood pressure during titration.
Avoid grapefruit products and limit alcohol and other CNS depressants to reduce oversedation.

Practice Notes

Schedule metabolic monitoring at baseline, 3 months, 6 months, and annually; escalate sooner if weight gain ≥5% or hyperglycemia emerges. Educate patients not to crush or chew XR tablets and to take them consistently with or without food.

Counsel on morning orthostasis and evening sedation; advise gradual position changes and consider bedtime dosing when daytime impairment emerges.
Assess for misuse when prescribing low-dose IR for sleep; reinforce appropriate indications.
Taper gradually to prevent withdrawal insomnia and relapse; restart titration if therapy lapses for ≥1 week.
Consider baseline and periodic eye exams during long-term therapy to address historical cataract concerns.
Coordinate bipolar maintenance plans with the bipolar disorder hub to align mood and metabolic monitoring.
Use the compare view to balance metabolic, prolactin, and sedation profiles when selecting or switching SGAs.

References

SEROQUEL XR prescribing information — DailyMed (2025)
Effectiveness of antipsychotic drugs in patients with chronic schizophrenia — The New England Journal of Medicine (2005)
Quetiapine Monotherapy IN Bipolar Depression: Randomized, Double Blind Trial — American Journal of Psychiatry (2010)
Continuation of quetiapine versus placebo or lithium for maintenance treatment of bipolar I disorder (Trial 144) — Journal of Clinical Psychiatry (2011)
Metabolic AND Endocrine Adverse Effects OF Second Generation Antipsychotics: A Systematic Review — CNS Drugs (2011)
The American Psychiatric Association Practice Guideline for the Treatment of Patients With Schizophrenia — American Psychiatric Association (2020)Guidelineschizophreniaclinical
CANMAT and ISBD 2018 guidelines for the management of patients with bipolar disorder — Bipolar Disorders (2018)