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 Ertuǧrul, A. Elif Anll Yaǧcloǧlu, 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 Rǎdulescu, 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 K.W. 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 J. Cubała, Muhammad Ayub, Alzira Silva, Raphael M. Bonelli, José M. Villagrán-Moreno, Benedicto Crespo-Facorro, Henk Temmingh, Eric Decloedt, Maria R. Pedro, Hiroyoshi Takeuchi, Masaru Tsukahara, Gerhard Gründer, Marina Sagud, Andreja Celofiga, Dragana Ignjatovic Ristic, Bruno B. Ortiz, Helio Elkis, António J. 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 journalReview articlepeer-review

25 Scopus citations


This international guideline proposes improving clozapine package inserts worldwide by using ancestry-based dosing and titration. Adverse drug reaction (ADR) databases suggest that clozapine is the third most toxic drug in the United States (US), and it produces four times higher worldwide pneumonia mortality than that by 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, the lowest dose; male smokers, the highest dose). Poor metabolizer 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. The Asian population (Pakistan to Japan) or the Americas' original inhabitants have lower CYP1A2 activity and require lower clozapine doses to reach concentrations of 350 ng/mL. In the US, daily doses of 300-600 mg/day are recommended. Slow personalized titration may prevent early ADRs (including syncope, myocarditis, and pneumonia). This guideline defines six personalized titration schedules for inpatients: 1) ancestry from Asia or the original people from the Americas with lower metabolism (obesity or valproate) needing minimum therapeutic dosages of 75-150 mg/day, 2) ancestry from Asia or the original people from the Americas with average metabolism needing 175-300 mg/day, 3) European/Western Asian ancestry with lower metabolism (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 with ancestries other than from Asia or the original people from the Americas with lower clozapine metabolism (obesity or valproate) needing 150-300 mg/day, and 6) in the US with ancestries other than from Asia or the original people from the Americas with average clozapine metabolism needing 300-600 mg/day. Baseline and weekly CRP monitoring for at least four weeks is required to identify any inflammation, including inflammation secondary to clozapine rapid titration.

Original languageEnglish
Pages (from-to)73-86
Number of pages14
Issue number2
StatePublished - Mar 1 2022

Bibliographical note

Funding Information:
reports consultation fees from Roche, Sunovion, Merck, Boehringer Ingelheim and Otsuka. He reports research support from Boehringer-Ingelheim, and GW Pharma. Dr. Citrome has engaged in collaborative research with, or received consulting or speaking fees, from: AbbVie, Acadia, Alexza, Alkermes, Allergan, Angelini, Astellas, AstraZeneca, Avanir, Axsome, BioXcel, Boehringer Ingel-heim, Bristol-Myers Squibb, Cadent Therapeutics, Eisai, Eli Lilly, Forum, Genentech, Impel, Indivior, Intra-Cellular Therapies, Jans-sen, Jazz, Karuna, Lundbeck, Luye, Lyndra, Medavante-Prophase, Meiji, Merck, Medivation, Mylan, Neurocrine, NeuroRx, Novartis, Noven, Osmotica, Otsuka, Pfizer, Reckitt ?enckiser, Relmada, Re-viva, Sage, Shire, Sunovion, Takeda, Teva, University of Arizona, Valeant, Vanda, and one-o ? ad hoc consulting for individuals/entities conducting marketing, commercial, or scientific scoping research. Dr. Freudenreich has the following financial relationship with a commercial interest to disclose (recipient SELF; content area SCHIZOPHRENIA): Alkermes – Research grant (to institution), consultant honoraria (Advisory Board); Avanir – Research grant (to institution); Janssen – Research grant (to institution), consultant honoraria (Advisory Board); Integral - Consultant honoraria; Neurocrine – Consultant honoraria (Advisory Board); Novartis – Consultant honoraria; Otsuka – Research grant (to institution); Roche – Consultant honoraria; Springer Verlag – Royalties (medical writer); Elsevier – Honoraria (medical editing); Global Medical Education – Honoraria (CME speaker and content developer); Medscape – Honoraria (CME speaker); American Psychiatric Association – Consultant honoraria (SMI Adviser); Wolters-Kluwer – Royalties (content developer); UpToDate – Royalties, honoraria (content developer and editor, including for a chapter on clozapine). Dr. Correll has been a consultant and/or advisor to or has received honoraria from: AbbVie, Acadia, Alkermes, Allergan, Angelini, Aristo, Axsome, Damitsa, Gedeon Richter, Hikma, IntraCellular Therapies, Janssen/ J&J, Karuna, LB Pharma, Lundbeck, MedAvante-ProPhase, MedIn-Cell, Medscape, Merck, Mitsubishi Tanabe Pharma, Mylan, Neurocrine, Noven, Otsuka, Pfizer, Recordati, Rovi, Servier, Sumitomo Dainippon, Sunovion, Supernus, Takeda, Teva, and Viatris. He provided expert testimony for Janssen and Otsuka. He served on a Data Safety Monitoring Board for Lundbeck, Rovi, Supernus, and Teva. He has received grant support from Janssen and Takeda. He received royalties from UpToDate and is also a stock option holder of LB Pharma. Dr. Müller reports he has been a co-investigator for two pharmacogenetic studies where genetic test kits were provided as an in-kind contribution by Myriad Neuroscience. He did not receive any payments or any equity, stocks, or options from any pharmacogenetic companies. He is also a co-inventor of two patents assessing risk for antipsychotic-induced weight gain (pending).

Funding Information:
Olmos, Ricciardi, Iglesias-Garcia, Iglesias-Alonso, Spina, Ruan, Chuan-Yue Wang, Gang Wang, Tang, Lin, Lane, Rajkumar, González-Esquivel, Jung-Cook, Baptista, Rohde, Nielsen, Verdoux, Quiles, Sanz, De las Cuevas, Cohen, Schulte, Chopra, McCollum, Shelton, Kaithi, Farooq, McGrane, Lana, Arrojo-Romero, Rădulescu, Every-Palmer, Bebawi, Bhattacharya, Otsuka, Lazary, Torres, Yecora, Motuca, Chan, Zolezzi, Ouanes, De Berardis, Grover, Kirilochev, Soloviev, Ayub, Silva, Bonelli, Temmingh, Decloedt, Pedro, Pacheco Palha, LLerena, Fernandez-Egea, Siskind, Masmoudi, Mohd Sa Can, Leung and ?uckley. In the last 3 years several authors report conflicts of interests. Dr. Seppälä is permanent medical advisor, received lecture fees and is an advisory board member from Viatris that markets clozapine in Finland and other European countries. Dr. Kopeček participated in speakers/advisory boards and lectured with the support of Angelini, Janssen Pharmaceuticals, Lundbeck and Richter Gedeon. Dr. Yong Sik Kim received grants, research support and honoraria from Janssen, Otsuka, Whan in Pharm and Bukwang Pharm (Sumitomo Dannipon Pharma). Dr. Se Hyun Kim received research grants from and/or served as a lecturer for Janssen, Eli Lilly, and Dongwha. Dr. Ertuğrul has received speaker’s honoraria from Abdi İbrahim Otsuka. Dr. Anıl Yağcıoğlu has received speaker’s honoraria and consulting fees from Janssen and Abdi İbrahim Otsuka. Dr. Cotes has received research funding from Otsuka, Lundbeck, Roche, Alkermes, and is a consultant for Saladax Biomedical. Dr. Kane reports personal fees from Alkermes, personal fees from Allergan, personal fees from Bristol-Myers Squibb, personal fees from IntraCellular Therapies, Janssen, Lundbeck, Minerva, Neurocrine, Otsuka, Pierre Fabre, Reviva, Sunovion, Takeda, Teva, outside-the-submitted work from LB Pharma, MedAvante and The Vanguard Research Group. Dr. Ng had served as consultant for Grunbiotics, Lundbeck, Servier, and Janssen-Cilag, and received research speaker honoraria from Servier, Janssen-Cilag and Pfizer.IMcG received royalties from Hogrefe Publishing Corp. T.L. Dr. Bilbily is supported by the National Institute on Drug Abuse training grant 5T32DA007261-30 (MPI). Dr. Hiemke received speaker’s honoraria from Otsuka. Dr. López-Jaramillo reports financial support for research from Financial support from the National Institute of Mental Health, USA, MinCiencias, Colombia and the Universidad de An-tioquia, Colombia. Dr. Eap received honoraria for conferences or teaching CME courses from Janssen-Cilag, Lundbeck, Otsuka, Sandoz, Servier, Sunovion, Vifor-Pharma, and Zeller. Dr. Seifritz has received honoraria from Schwabe GmbH for educational lectures. He has further received educational grants and consulting fees from Janssen Cilag, Lundbeck, Angelini, Otsuka, Servier, Recordati, Vifor, Sunovion, and Mepha. Dr. Bousman is a member of the Clinical Pharmacogenetics Implementation Consortium (CPIC) and Phar-macogene Variation Consortium (PharmVar). Dr. Kelly has served as a consultant for Alkermes, Lyndra and Sunovion. Dr. Procyshyn has been on the speaker's bureau and attended advisory board meetings for Janssen, Lundbeck, and Otsuka. Dr. Adebayo was on the advisory board of Janssen for a Long Acting Injectable Paliperidone palmitate in Nigeria. Janssen is not involved in Clozapine in Nigeria. Dr. Fountoulakis has received grants in the past, served as

Publisher Copyright:
© 2022 Georg Thieme Verlag. All rights reserved.


  • American continental ancestry group
  • Asian continental ancestry group
  • CYP1A2
  • European continental ancestry group
  • Native
  • clozapine/adverse effects
  • clozapine/blood
  • clozapine/metabolism
  • clozapine/therapeutic use
  • clozapine/toxicity
  • drug labeling
  • infection
  • inflammation
  • mortality/drug effects
  • sex
  • smoking.

ASJC Scopus subject areas

  • Psychiatry and Mental health
  • Pharmacology (medical)


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