Zyprexa Tapering Guide
olanzapine
Boxed Warning
Increased mortality in elderly patients with dementia-related psychosis. Post-injection delirium/sedation syndrome with extended-release IM formulation (Zyprexa Relprevv).
Overview
Olanzapine is an atypical antipsychotic approved for schizophrenia and bipolar disorder (manic/mixed episodes, maintenance, and bipolar depression in combination with fluoxetine). It is effective but carries the highest metabolic risk among atypical antipsychotics.
2.5mg, 5mg, 10mg, 15mg, 20mg
Tablets: 2.5mg, 5mg, 7.5mg, 10mg, 15mg, 20mg; Orally disintegrating tablets (Zydis): 5mg, 10mg, 15mg, 20mg; Intramuscular injection: 10mg; Extended-release injection (Zyprexa Relprevv): 210mg, 300mg, 405mg
Category C (risk cannot be ruled out)
Mechanism of Action
Antagonist at dopamine D1–D4, serotonin 5-HT2A/2C/3/6, histamine H1, muscarinic M1–M5, and alpha-1 adrenergic receptors. The broad receptor profile contributes to efficacy but also drives significant weight gain and metabolic effects.
Taper Notes
Tablets can be split. Weight gain reversal during tapering. Rebound insomnia common.
Hyperbolic Tapering Guidance
Slow gradual taper essential. Tablets available in small increments (2.5mg). Monitor for supersensitivity symptoms.
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
Interactions & Safety
Drug Interactions
- CYP1A2 inhibitors (fluvoxamine, ciprofloxacin) increase olanzapine levels — reduce dose
- CYP1A2 inducers (smoking, carbamazepine) decrease olanzapine levels — dose adjustment needed (smokers need higher doses)
- CNS depressants — additive sedation
Food Interactions
- Food does not significantly affect absorption
- Avoid alcohol (additive CNS depression)
Contraindications
- Known hypersensitivity to olanzapine
Toxicity
Significant metabolic syndrome (weight gain, hyperglycemia, diabetes, dyslipidemia — highest among atypical antipsychotics). Sedation. Orthostatic hypotension. Tardive dyskinesia. NMS rarely.
Pharmacokinetics
ADME Profile
Well absorbed after oral administration. Bioavailability ~60% due to first-pass metabolism. Tmax ~6 hours. Food does not significantly affect absorption.
~1000 L (~14 L/kg)
Extensively metabolized hepatically via CYP1A2 (primary) and CYP2D6 via glucuronidation and oxidation. Major metabolites (10-N-glucuronide and 4'-N-desmethyl) are inactive.
Renal (~57%) and fecal (~30%). Approximately 7% excreted unchanged in urine.
~93%
~26 L/hr (apparent oral clearance)
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Other Drug Profiles
Sources & References
Zyprexa (olanzapine) information on this page is sourced from peer-reviewed research, regulatory bodies, clinical guidelines, and patient-advocacy organizations.
Encyclopedic & chemical databases
Neutral, high-authority entity references.
Peer-reviewed research
Primary literature cited in this taper guide.
- Horowitz MA, Jauhar S, Natesan S, Murray RM, Taylor D 2021 — A method for tapering antipsychotic treatment that may minimize the risk of relapse (Schizophrenia Bulletin)
- Tranter R, Healy D 1998 — Antipsychotic withdrawal symptoms: phenomenology and pathophysiology (Journal of Psychopharmacology)
- Davies J, Read J 2019 — A systematic review into the incidence, severity and duration of antidepressant withdrawal effects (Addictive Behaviors)
Clinical guidelines
Evidence-based deprescribing and prescribing standards.
Deprescribing-specific resources
Clinician-facing references on tapering protocols.
- Royal College of Psychiatrists — Antipsychotics — UK clinical guidance on antipsychotic prescribing and discontinuation
- Council for Evidence-Based Psychiatry (CEP UK) — Evidence-based critique of long-term antipsychotic prescribing
- Deprescribing.org — Antipsychotic deprescribing algorithm for insomnia and BPSD
Patient-advocacy & lived-experience
Long-running communities documenting withdrawal experience.
- Surviving Antidepressants — antipsychotic tapering forum — Community archive of antipsychotic taper experiences
- Mad in America — antipsychotic archive — Independent journalism on antipsychotics and withdrawal
- Inner Compass Initiative — Withdrawal Project — Peer-led psychiatric drug withdrawal resources
- RxISK — adverse drug reaction reporting — Independent database of antipsychotic adverse-effect reports
TaperCommunity does not provide medical advice. Always consult a qualified prescriber before adjusting psychiatric medication.