olanzapine pamoate

General information

• Class: Long-acting injectable antipsychotic
• Common US brands: ZYPREXA RELPREVV
• Typical dose range: Administration is deep intramuscular injection (commonly gluteal). Dose and interval (q2–4 weeks) are individualized to symptom control and tolerability within labeled schedules.
• Long-acting injectable formulation available.
• Therapeutic drug monitoring not routinely recommended.
• Last reviewed: 2025-12-30

Dosing & forms

• Forms/strengths: Deep intramuscular injection every 2–4 weeks (dose/interval per label).
• Typical range: Administration is deep intramuscular injection (commonly gluteal). Dose and interval (q2–4 weeks) are individualized to symptom control and tolerability within labeled schedules.

Mechanism (brief)

Long-acting injectable olanzapine formulation (D2/5-HT2A antagonist with strong H1 and muscarinic activity) used for schizophrenia maintenance; requires post-injection observation due to PDSS risk.

Metabolism & Half‑life

• Metabolism: CYP1A2, CYP2D6 (minor)
• Half‑life: Steady-state mean 720 h

Therapeutic Drug Monitoring (TDM)

Recommended: No

Long‑acting injectable (LAI)

Monitoring highlights

• Post-injection observation per label after every dose; monitor for sedation, delirium symptoms, and impaired coordination.
• Weight/BMI and waist circumference; fasting lipids and glucose/HbA1c at baseline and periodically.
• Blood pressure/orthostasis monitoring in older adults or antihypertensive co-use.
• Bowel function and anticholinergic burden (constipation risk).
• Movement disorder monitoring (parkinsonism, tardive dyskinesia) as clinically indicated.

Sources

• ZYPREXA RELPREVV (olanzapine pamoate) extended-release injectable suspension — Prescribing Information — DailyMed (2025)
• ZYPREXA (olanzapine) label — DailyMed (2025)
• The American Psychiatric Association Practice Guideline for the Treatment of Patients With Schizophrenia — American Psychiatric Association (2020)
• Post-Injection Delirium/Sedation Syndrome in Patients Treated with Olanzapine Pamoate: Mechanism, Incidence, and Management — CNS Drugs (2015)