Patient & Dosing

Total daily clozapine dose (mg/day)

Sex assigned at birth

Age (years)

Smoking status

Inhibitors

Strong 1A2 inhibitors (e.g., fluvoxamine, ciprofloxacin, enoxacin, Qelbree® [viloxazine]) Strong 2D6/3A4 inhibitors (e.g., paroxetine, fluoxetine, diltiazem, macrolides, azoles) High caffeine intake (≈400–1000 mg/day) Depakote® [valproic acid]

Inducers

Omeprazole Carbamazepine Phenytoin Phenobarbital Rifampin St John's wort

Inflammation / Illness

Acute serious infection (systemic symptoms) Recent COVID‑19 vaccination

Actual lab levels (optional)

Actual clozapine (ng/mL)

Actual norclozapine (ng/mL)

Sources: Meyer & Stahl, The Clinical Use of Antipsychotic Plasma Levels (Stahl's Handbooks, Cambridge University Press, 2021), Ch. 13 (Clozapine). Age effect per Reeves et al. 2024 (Br J Clin Pharmacol 90:135–145). Body weight is not modeled: published data disagree on its direction (Diaz 2018 and the Rostami-Hodjegan 2004 nomogram found higher levels in heavier patients; Reeves 2024 scaled the other way).

Results

Clozapine (12‑h trough)

—

Norclozapine (12‑h trough)

—

MR = —

Interpretation

—

—

Factors summary

Dose–Concentration curve (with current modifiers)

Click the chart to read coordinates.

Feedback: Actual vs Expected

Enter actual lab values to get tailored suggestions.

Disclaimer. This educational tool estimates steady‑state trough concentrations from published nomograms and typical interaction effects. Real patients can vary substantially (~±30%) due to sampling time, adherence, labs, and biology; confirm with therapeutic drug monitoring and clinical judgment.