[Pharmacogenetic study of the response to flecainide and propafenone in patients with atrial fibrillation]. / Estudio farmacogenético de la respuesta a flecainida y propafenona en pacientes con fibrilación auricular.

We analyzed cytochrome P450 2D6 polymorphism by determining phenotype as the metabolic ratio between dextromethorphan and its main metabolite, dextrorphan. We studied 18 men and 22 women in whom mean age was 54.6+/-11.9 years. In 9 patients metabolic ratio was determined before antiarrhythmic treatment and again during treatment, with a mean increase of 0.13+/-0.15 (P=.03). We found 19 poor metabolizers and 21 extensive metabolizers. Adverse effects were more frequent in poor metabolizers (21.1%) than in extensive metabolizers (4.8%; P=.12). Antiarrhythmic treatment was effective in 27 patients (67.5%), with no difference between poor and extensive metabolizers.

Estudio farmacogenético de la respuesta a flecainida y propafenona en pacientes con fibrilación auricular / Pharmacogenetic study of the response to flecainide and propafenone in patients with atrial fibrillation

Se analizó el polimorfismo del citocromo P450-2D6 mediante la determinación del fenotipo, utilizando la ratio entre dextrometorfano y su metabolito dextrorfano. Estudiamos a 18 varones y 22 mujeres, con una edad media de 54,6 ± 11,9 años. En 9 pacientes se realizó una determinación de la ratio metabólica antes de iniciar el tratamiento antiarrítmico y una segunda determinación bajo tratamiento, con un incremento promedio de 0,13 ± 0,15 (p = 0,03). De los 40 pacientes, 19 eran metabolizadores lentos y 21 metabolizadores rápidos. Los efectos secundarios fueron más frecuentes en los metabolizadores lentos (21,1%) que en los metabolizadores rápidos (4,8%) (p = 0,12). El tratamiento antiarrítmico fue eficaz en 27 pacientes (67,5%), con un porcentaje similar en metabolizadores lentos y rápidos

We analyzed cytochrome P450 2D6 polymorphism by determining phenotype as the metabolic ratio between dextromethorphan and its main metabolite, dextrorphan. We studied 18 men and 22 women in whom mean age was 54.6±11.9 years. In 9 patients metabolic ratio was determined before antiarrhythmic treatment and again during treatment, with a mean increase of 0.13±0.15 (P=.03). We found 19 poor metabolizers and 21 extensive metabolizers. Adverse effects were more frequent in poor metabolizers (21.1%) than in extensive metabolizers (4.8%; P=.12). Antiarrhythmic treatment was effective in 27 patients (67.5%), with no difference between poor and extensive metabolizers