Seroquel Tapering Guide

Q: What are the withdrawal symptoms of Seroquel (quetiapine)?

Common withdrawal symptoms of Seroquel (quetiapine) include: rebound insomnia, nausea, anxiety, irritability, sweating, psychosis risk at high doses. Symptom severity varies by individual, dose, and duration of use.

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

Widely prescribed off-label for insomnia at low doses, where strong H1 antagonism dominates. Rebound histaminergic insomnia and cholinergic rebound are predominant withdrawal features. Tablets are scored and can be split. Monitor for psychosis re-emergence in patients with primary psychiatric indication.

Maudsley Deprescribing Guidance

Reduce by no more than 10% of current dose per step. At low off-label doses (25–50 mg for sleep), apply hyperbolic reductions over months. At antipsychotic doses, monitor for relapse and dopamine supersensitivity.

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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