From the Guidelines
Olanzapine dosing should start at 2.5-5 mg once daily for adults, with gradual titration based on response and tolerability, as recommended by the most recent guidelines 1. The effective dose range is usually 5-20 mg daily, with a maximum recommended dose of 20 mg per day. For elderly patients or those with hepatic impairment, starting at 2.5 mg is recommended with more cautious titration, as stated in the guidelines 1. Some key points to consider when dosing olanzapine include:
- The once-daily dose is typically administered in the evening due to its sedative effects.
- For acute agitation, the orally disintegrating tablet (Zyprexa Zydis) or intramuscular formulation may be used, with the latter dosed at 2.5-10 mg as needed, as per the guidelines 1.
- Treatment duration varies by condition - for schizophrenia, long-term maintenance is often necessary, while for bipolar disorder, the duration depends on the phase being treated.
- Olanzapine works primarily by blocking dopamine D2 and serotonin 5-HT2A receptors, which helps control psychotic symptoms and mood stabilization.
- Patients should be monitored for metabolic side effects including weight gain, hyperglycemia, and dyslipidemia, as well as potential extrapyramidal symptoms, though these are less common than with typical antipsychotics, as noted in the guidelines 1. It's worth noting that the guidelines from 2002 1 are outdated and should not be used for current clinical practice, as the more recent guidelines from 2018 1 provide more up-to-date and evidence-based recommendations for olanzapine dosing.
From the FDA Drug Label
1 Schizophrenia Adults Dose Selection — Oral olanzapine should be administered on a once-a-day schedule without regard to meals, generally beginning with 5 to 10 mg initially, with a target dose of 10 mg/day within several days Further dosage adjustments, if indicated, should generally occur at intervals of not less than 1 week, since steady state for olanzapine would not be achieved for approximately 1 week in the typical patient. When dosage adjustments are necessary, dose increments/decrements of 5 mg QD are recommended.
2 Bipolar I Disorder (Manic or Mixed Episodes) Adults Dose Selection for Monotherapy — Oral olanzapine should be administered on a once-a-day schedule without regard to meals, generally beginning with 10 or 15 mg. Dosage adjustments, if indicated, should generally occur at intervals of not less than 24 hours, reflecting the procedures in the placebo-controlled trials When dosage adjustments are necessary, dose increments/decrements of 5 mg QD are recommended.
The recommended dosing for olanzapine is as follows:
- For schizophrenia in adults, the initial dose is 5-10 mg once daily, with a target dose of 10 mg/day.
- For bipolar I disorder (manic or mixed episodes) in adults, the initial dose is 10-15 mg once daily.
- Dose adjustments should be made at intervals of at least 1 week for schizophrenia and 24 hours for bipolar I disorder.
- Dose increments/decrements of 5 mg are recommended for adults 2.
From the Research
Olanzapine Dosing Overview
- The recommended starting dosage of olanzapine is 5-10 mg orally once daily 3.
- Efficacy beyond six weeks has not been evaluated; patients treated for longer than six weeks should be periodically reassessed 3.
Dosing Above the Licensed Range
- A substantial number of patients with schizophrenia or bipolar disorder receive olanzapine in amounts that are greater than what is recommended in the product labeling approved by drug regulatory agencies 4.
- The use of olanzapine at doses greater than 20 mg/day appears to be increasing, with some case reports describing a favorable benefit-risk ratio at doses up to 60 mg/day 4.
- Double-blind clinical trials suggest that doses greater than 20 mg/day may be helpful in selected patients who are treatment resistant, have high levels of psychopathology, or who are acutely agitated 4.
Special Populations
- In adolescents with schizophrenia or bipolar I disorder, olanzapine has been shown to be effective in reducing symptoms, with a recommended dosage of 5-10 mg orally once daily 5.
- However, olanzapine-treated adolescents are likely to experience greater increases in bodyweight, sedation, blood lipids, serum prolactin, and liver transaminase levels than olanzapine-treated adults 5.
Combination Therapy
- Combination of olanzapine with samidorphan (OLZ/SAM) has been shown to result in significantly less weight gain than olanzapine monotherapy, with improvements in symptoms of psychosis and overall satisfaction with treatment 6.
- OLZ/SAM has been shown to be a safe and effective pharmaceutical option for the clinical management of schizophrenia and bipolar I disorder 6.