What is the recommended starting dose of Zyprexa (olanzapine)?

Zyprexa (Olanzapine) Starting Dose

For adults with schizophrenia or bipolar I disorder, start Zyprexa at 5-10 mg once daily, with most patients targeting 10 mg/day within several days. 1

Standard Adult Dosing

Schizophrenia

• Initial dose: 5-10 mg once daily 1
• Target dose: 10 mg/day within several days 1
• Administer without regard to meals 1
• Dose adjustments should occur at intervals of at least 1 week (time to steady state) 1
• When adjustments are needed, use increments/decrements of 5 mg 1
• Efficacy demonstrated in the 10-15 mg/day range, though doses above 10 mg/day showed no additional benefit over 10 mg/day in trials 1

Bipolar I Disorder (Manic or Mixed Episodes)

• Initial dose: 10-15 mg once daily for monotherapy 1
• Initial dose: 10 mg once daily when used adjunctively with lithium or valproate 1
• Dose adjustments should occur at intervals of at least 24 hours 1
• Efficacy demonstrated in 5-20 mg/day range 1

Special Populations Requiring Lower Starting Doses

Elderly, Debilitated, or High-Risk Patients

• Start at 5 mg once daily 1
• This lower dose applies to patients who are debilitated, have predisposition to hypotensive reactions, or exhibit factors causing slower olanzapine metabolism (e.g., nonsmoking females ≥65 years) 1
• Dose escalation should be performed with caution in these patients 1

Dementia-Related Agitation (Alzheimer's Disease)

• Start at 2.5 mg once daily at bedtime 2
• Maximum dose: 10 mg/day, usually divided twice daily 2
• This population requires particularly cautious dosing due to increased sensitivity 2

Hepatic Impairment or Alzheimer's-Related Agitation

• Start at 2.5 mg once daily 3
• Exercise particular caution when combining with benzodiazepines due to risks of oversedation, respiratory depression, and reported fatalities 3

Adolescent Dosing (Ages 13-17)

Schizophrenia or Bipolar I Disorder

• Initial dose: 2.5-5 mg once daily 1
• Target dose: 10 mg/day 1
• Mean modal dose in trials was 12.5 mg/day for schizophrenia and 10.7 mg/day for bipolar disorder 1
• Use dose increments/decrements of 2.5-5 mg when adjustments are necessary 1
• Safety and efficacy above 20 mg/day not established in adolescents 1

Critical Dosing Considerations

Pharmacokinetic Profile

• Peak plasma levels reached in 5-8 hours 4
• Half-life approximately 35 hours 4
• Steady state achieved in approximately 1 week 1
• Food does not affect absorption 5

Common Pitfalls to Avoid

• Do not increase doses more frequently than weekly intervals in adults with schizophrenia, as steady state requires approximately 1 week 1
• Avoid starting at high doses (>10 mg) in elderly or debilitated patients, as this increases risk of hypotension and falls 1
• Do not exceed 20 mg/day without clear clinical justification, as this is the maximum FDA-approved dose and higher doses increase risk of weight gain and elevated prolactin 1, 6
• Exercise caution with benzodiazepine combinations, particularly in elderly or hepatically impaired patients, due to oversedation and respiratory depression risks 3

Monitoring Requirements

• Weight gain occurs in approximately 40% of patients, especially with high starting doses and in underweight patients 4
• Monitor for metabolic effects including weight, glucose, and lipids with long-term use 3
• QTc prolongation can occur at maximum doses, though olanzapine has the least effect among atypical antipsychotics studied 2
• Unlike clozapine, olanzapine does not cause agranulocytosis and does not require routine blood monitoring 5, 7