Clozapine Dose Titration Calculator
This educational tool provides ancestry-based inpatient titration schedules for clozapine initiation derived from international consensus guidelines (de Leon et al., 2022). Individual patients may require slower titration due to tolerability issues (orthostatic hypotension, tachycardia, sedation) or faster titration in certain clinical circumstances. These schedules represent starting frameworks, not rigid protocols. Always confirm appropriateness with CRP monitoring, vital signs, clinical assessment, and therapeutic drug monitoring.
Instructions for Proper Use
- Select the patient’s ancestry/ethnicity, biological sex, smoking status, and age group.
- Review Poor Metabolizer (PM) criteria and select any that apply—one or more factors will trigger the slower PM titration schedule.
- The calculator will automatically display the recommended titration schedule with target doses.
- If there are signs of infection, inflammation, obtain baseline CRP before initiating clozapine; do not start if CRP is elevated. Monitor CRP weekly for the first 4 weeks. If CRP rises or fever develops, hold dose escalation until normalized to avoid myocarditis risk.
- Slow or pause titration if orthostatic hypotension, tachycardia, or severe sedation occurs.
- Do not taper prior antipsychotic(s) until at least Week 4 AND plasma clozapine concentration ≥350 ng/mL.
- After reaching target dose, obtain trough clozapine level to guide further adjustments, and use the clozapine concentration calculator to interpret the results.
The calculator was developed by Bruce Bassi MD, an inpatient and outpatient psychiatrist who regularly uses clozapine in his practice. The calculator was created with the use of AI and the references cited below. You are welcome to submit feedback.
Titration Settings
Baseline Titration ScheduleDemographics
AncestryPM Criteria
Slows titration & reduces target dose.
General Recommendations
Warnings & Precautions
- Do not start clozapine with powerful CYP1A2 inhibitors (e.g., fluvoxamine)
- Slow titration if patient develops orthostatic hypotension, tachycardia, or severe sedation
- Do not decrease prior antipsychotic(s) until Week 4 or later AND plasma clozapine ≥350 ng/mL
CRP Monitoring
- Measure CRP at baseline and weekly during the first 4 weeks
- Abnormal baseline CRP indicates possible infection — do not start until normalized
- Fever and/or abnormal CRP during titration may indicate clozapine-induced inflammation
- Do not increase dose until CRP normalizes — continuing may lead to myocarditis
- Abnormal CRP can also indicate rare (~1%) genetic poor metabolizers
References
Sources:
Teva Clozapine Example Titration Schedule. TevaClozapine.com.
Oxford Health NHS Foundation Trust. Clozapine Outpatient Titration Protocol. Jan 2024.
de Leon J, et al. An International Adult Guideline for Making Clozapine Titration Safer by Using Six Ancestry-Based Personalized Dosing Titrations, CRP, and Clozapine Levels. Pharmacopsychiatry. 2022;55(2):73-86.
This tool provides general guidance based on published guidelines and should not replace clinical judgment. Always consider individual patient factors and local protocols.
