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Second-Generation Antipsychotic

Olanzapine

Brand names: Zyprexa

Olanzapine is a second-generation (atypical) antipsychotic used in schizophrenia and bipolar disorder.

Dosing — being independently re-sourced

ClinCalc Pro is rebuilding its dose data from primary open sources — the manufacturer SmPC (eMC), the WHO Model Formulary and other official references — under clinician review. This drug's structured dose is not yet published here. Confirm all doses against the product SmPC and your local formulary before prescribing.

US labelling (FDA)

Reference — US labelling, may differ from UK

Schizophrenia in adults ( 2.1 ) Oral: Start at 5 mg to 10 mg once daily; Target: 10 mg/day within several days Schizophrenia in adolescents ( 2.1 ) Oral: Start at 2.5 mg to 5 mg once daily; Target: 10 mg/day Bipolar I Disorder (manic or mixed episodes) in adults ( 2.2 ) Oral: Start at 10 mg or 15 mg once daily Bipolar I Disorder (manic or mixed episodes) in adolescents ( 2.2 ) Oral: Start at 2.5 mg to 5 mg once daily; Target: 10 mg/day Bipolar I Disorder (manic or mixed episodes) with lithium or valproate in adults ( 2.2 ) Oral: Start at 10 mg once daily Depressive Episodes associated with Bipolar I Disorder in adults ( 2.5 ) Oral in combination with fluoxetine: Start at 5 mg of oral …

Source: US FDA prescribing information (openFDA / DailyMed), label dated 2023-07-10. Accessed 2026-06-12. US dosing and indications can differ from UK practice — use UK sources for prescribing decisions.

Clinical monograph

How it works

It antagonises dopamine D2, serotonin 5-HT2 and other receptors.

Prescribing in practice

  • Marked metabolic effects (weight gain, raised glucose and lipids) are characteristic — monitor and manage cardiometabolic risk.
  • In older people with dementia, antipsychotics increase the risk of stroke and death — use only when necessary, at the lowest dose for the shortest time.
  • Sedation and postural hypotension occur; do not stop abruptly.

Monitoring

Monitor weight, glucose (HbA1c), lipids, blood pressure and (where relevant) ECG; review the need to continue.

Counselling the patient

  • Weight gain and increased appetite are common — attention to diet and activity helps.
  • Sedation can occur.
  • Do not stop it suddenly.

Evidence & guidelines

Used in schizophrenia and bipolar disorder; notable for metabolic effects, with the dementia stroke/mortality warning (MHRA; NICE).

Reference: MHRA Drug Safety Update 2004 and 2009 (antipsychotics in dementia); AGS Beers Criteria 2023; STOPP/START v3; Drug verified in RxNorm (NLM); confirm dosing against the manufacturer SPC (eMC). Verify against your local formulary and current prescribing references before prescribing. Monograph status: clinician-reviewed (2026-07-04).

Related

Curated clinical cross-links plus same-class fallbacks.

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