An international adult guideline for making clozapine titration safer by using six ancestry-based personalized dosing titrations, CRP, and clozapine levels

Jose de Leon, Georgios Schoretsanitis, Robert L. Smith, Espen Molden, Anssi Solismaa, Niko Seppälä, Miloslav Kopeček, Patrik Švancer, Ismael Olmos, Carina Ricciardi, Celso Iglesias-Garcia, Ana Iglesias-Alonso, Edoardo Spina, Can Jun Ruan, Chuan Yue Wang, Gang Wang, Yi Lang Tang, Shih Ku Lin, Hsien Yuan Lane, Yong Sik KimSe Hyun Kim, Anto P. Rajkumar, Dinora F. González-Esquivel, Helgi Jung-Cook, Trino Baptista, Christopher Rohde, Jimmi Nielsen, Hélène Verdoux, Clelia Quiles, Emilio J. Sanz, Carlos De las Cuevas, Dan Cohen, Peter F.J. Schulte, Aygün Ertuğrul, A. Elif Anıl Yağcıoğlu, Nitin Chopra, Betsy McCollum, Charles Shelton, Robert O. Cotes, Arun R. Kaithi, John M. Kane, Saeed Farooq, Chee H. Ng, John Bilbily, Christoph Hiemke, Carlos López-Jaramillo, Ian McGrane, Fernando Lana, Chin B. Eap, Manuel Arrojo-Romero, Flavian Ştefan Rădulescu, Erich Seifritz, Susanna Every-Palmer, Chad A. Bousman, Emmanuel Bebawi, Rahul Bhattacharya, Deanna L. Kelly, Yuji Otsuka, Judit Lazary, Rafael Torres, Agustin Yecora, Mariano Motuca, Sherry Kit Wa Chan, Monica Zolezzi, Sami Ouanes, Domenico De Berardis, Sandeep Grover, Ric M. Procyshyn, Richard A. Adebayo, Oleg O. Kirilochev, Andrey Soloviev, Konstantinos N. Fountoulakis, Alina Wilkowska, Wiesław Jerzy Cubała, Muhammad Ayub, Alzira Silva, Raphael M. Bonelli, José María Villagrán-Moreno, Benedicto Crespo-Facorro, Henk Temmingh, Eric Decloedt, Maria Rosel Pedro, Hiroyoshi Takeuchi, Masaru Tsukahara, Gerhard Gründer, Marina Sagud, Andreja Celofiga, Dragana Ignjatovic Ristic, Bruno Bertolucci Ortiz, Helio Elkis, António José Pacheco Palha, Adrián Llerena, Emilio Fernandez-Egea, Dan Siskind, Abraham Weizman, Rim Masmoudi, Shamin Mohd Saffian, Jonathan G. Leung, Peter F. Buckley, Stephen R. Marder, Leslie Citrome, Oliver Freudenreich, Christoph U. Correll, Daniel J. Müller

Research output: Contribution to journalArticlepeer-review


This is the Spanish translation of an international guideline which proposes improving clozapine package inserts worldwide by using ancestry-based: 1) dosing and 2) titration. Adverse drug reaction (ADR) databases suggest clozapine: 1) is the third most toxic drug in the United States (US), and 2) produces worldwide pneumonia mortality four times greater than that of agranulocytosis or myocarditis. For trough steady-state clozapine serum concentrations, the therapeutic reference range is narrow, from 350 to 600 ng/mL with the potential for toxicity and ADRs as concentrations increase. Clozapine is mainly metabolized by CYP1A2 (female non-smokers require the lowest dose and male smokers the highest dose). Poor metabolizer (PM) status through phenotypic conversion is associated with co-prescription of inhibitors (including oral contraceptives and valproate), obesity or inflammation with C-reactive protein (CRP) elevations. People with ancestry from Asia (Pakistan to Japan) or the Americas’ original inhabitants have lower CYP1A2 activity and require lower clozapine doses to reach concentrations of 350 ng/ml. Daily doses of 300-600 mg/day are recommended in the US. Slow personalized titration may prevent early ADRs (including syncope, myocarditis and pneumonia). The core of this guideline consists of six personalized titration schedules for inpatients: 1) Asian/Amerindian ancestry with lower metabolism (in cases of obesity or valproate) needing minimum therapeutic dosages of 75-150 mg/day, 2) Asian/Amerindian ancestry with average metabolism needing 175-300 mg/day, 3) European/Western Asian ancestry with lower metabolism (in cases of obesity or valproate) needing 100-200 mg/day, 4) European/Western Asian ancestry with average metabolism needing 250-400 mg/day, 5) in the US of non-Asian/Amerindian ancestry with lower clozapine metabolism (in cases of obesity or valproate) needing 150-300 mg/day, and 6) in the US of non-Asian/Amerindian ancestry with average clozapine metabolism needing 300-600 mg/day. Baseline and weekly CRP monitoring for at least 4 weeks is required to identify any inflammation, including inflammation secondary to clozapine rapid titration.

Original languageEnglish
Article number100415
JournalPsiquiatria Biologica
Issue number3
StatePublished - Sep 1 2023

Bibliographical note

Publisher Copyright:
© 2023 Elsevier España, S.L.U.


  • Asian continental ancestry group
  • CYP1A2
  • Clozapine/adverse effects
  • Clozapine/blood
  • Clozapine/metabolism
  • Clozapine/therapeutic use
  • Clozapine/toxicity
  • Drug labeling
  • European continental ancestry group
  • Infection
  • Inflammation
  • Mortality/drug effects
  • Native American continental ancestry group
  • Sex
  • Smoking

ASJC Scopus subject areas

  • Psychiatry and Mental health


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