TaperCommunityquetiapine
Boxed Warning
Increased mortality in elderly patients with dementia-related psychosis. Suicidality risk in children, adolescents, and young adults (for MDD adjunct indication).
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.
25mg, 50mg, 100mg, 200mg, 300mg
Immediate-release tablets: 25mg, 50mg, 100mg, 200mg, 300mg, 400mg; Extended-release tablets (XR): 50mg, 150mg, 200mg, 300mg, 400mg
Category C (risk cannot be ruled out)
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.
Often prescribed off-label for insomnia at low doses. Rebound insomnia and anxiety common during tapering. Tablets can be split.
Reduce by no more than 10% of current dose. At low doses (25–50mg) used for sleep, very slow final taper over months.
Toxicity
Metabolic syndrome (weight gain, dyslipidemia, hyperglycemia, diabetes). Orthostatic hypotension. QT prolongation. Somnolence. Tardive dyskinesia with long-term use.
Pharmacokinetics
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.
~10 L/kg
Extensively metabolized hepatically via CYP3A4 (primary) to the active metabolite norquetiapine and inactive sulfoxide metabolite.
Renal (~73%) and fecal (~20%). Less than 1% excreted unchanged.
~83%
~100 L/hr (apparent oral clearance)
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