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Seroquel Tapering Guide

quetiapine

Atypical AntipsychoticFDA 1997
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Boxed Warning

Increased mortality in elderly patients with dementia-related psychosis. Suicidality risk in children, adolescents, and young adults (for MDD adjunct indication).

Overview

Quetiapine is an atypical antipsychotic approved for schizophrenia, bipolar disorder (manic and depressive episodes), and as adjunctive treatment for major depressive disorder. It is widely prescribed off-label at low doses for insomnia and anxiety.

Common Doses

25mg, 50mg, 100mg, 200mg, 300mg

Formulations

Immediate-release tablets: 25mg, 50mg, 100mg, 200mg, 300mg, 400mg; Extended-release tablets (XR): 50mg, 150mg, 200mg, 300mg, 400mg

Pregnancy

Category C (risk cannot be ruled out)

Mechanism of Action

Antagonist at dopamine D2, serotonin 5-HT2A, histamine H1, and alpha-1 adrenergic receptors. Its active metabolite norquetiapine also inhibits the norepinephrine transporter. The strong H1 antagonism drives sedation; 5-HT2A/D2 ratio contributes to atypical antipsychotic profile.

Taper Notes

Often prescribed off-label for insomnia at low doses. Rebound insomnia and anxiety common during tapering. Tablets can be split.

Hyperbolic Tapering Guidance

Reduce by no more than 10% of current dose. At low doses (25–50mg) used for sleep, very slow final taper over months.

Summary written by TaperCommunity, informed by the Maudsley Deprescribing Guidelines (Horowitz & Taylor) and related literature — see Sources & References below. Not affiliated with or endorsed by the Maudsley.

Common Withdrawal Symptoms

rebound insomnianauseaanxietyirritabilitysweatingpsychosis risk at high doses

Interactions & Safety

Drug Interactions

  • CYP3A4 inhibitors (ketoconazole, erythromycin, nefazodone) significantly increase quetiapine levels — reduce quetiapine dose
  • CYP3A4 inducers (phenytoin, carbamazepine, rifampin) decrease quetiapine levels significantly
  • CNS depressants — additive sedation

Food Interactions

  • High-fat meals increase XR formulation absorption
  • Avoid alcohol (additive CNS depression)
  • Grapefruit juice may increase levels via CYP3A4 inhibition

Contraindications

  • Known hypersensitivity to quetiapine

Toxicity

Metabolic syndrome (weight gain, dyslipidemia, hyperglycemia, diabetes). Orthostatic hypotension. QT prolongation. Somnolence. Tardive dyskinesia with long-term use.

Pharmacokinetics

ADME Profile

Absorption

Rapidly absorbed after oral administration. Tmax ~1.5 hours (IR), ~6 hours (XR). Bioavailability ~100% relative to oral solution. Food increases Cmax by ~25% for IR; high-fat food increases XR Cmax and AUC.

Distribution

~10 L/kg

Metabolism

Extensively metabolized hepatically via CYP3A4 (primary) to the active metabolite norquetiapine and inactive sulfoxide metabolite.

Elimination

Renal (~73%) and fecal (~20%). Less than 1% excreted unchanged.

Protein Binding

~83%

Clearance

~100 L/hr (apparent oral clearance)

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Sources & References

Seroquel (quetiapine) information on this page is sourced from peer-reviewed research, regulatory bodies, clinical guidelines, and patient-advocacy organizations.

Regulatory sources

Official prescribing information and safety notices.

Clinical guidelines

Evidence-based deprescribing and prescribing standards.

Deprescribing-specific resources

Clinician-facing references on tapering protocols.

Patient-advocacy & lived-experience

Long-running communities documenting withdrawal experience.

TaperCommunity does not provide medical advice. Always consult a qualified prescriber before adjusting psychiatric medication.