Guía internacional para una dosificación más segura de la clozapina en adultos mediante el uso de 6 titulaciones personalizadas de dosis basados en la etnicidad, la proteína C reactiva y los niveles de clozapina

Abstract

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.