Referenced in: none

Automatically associated channels: Kv11.1

Title: KCNH2 polymorphism and methadone dosage interact to enhance QT duration.

Authors: Aline Hajj, Kamilia Ksouda, Katell Peoc'h, Emmanuel Curis, Anne Messali, Laurence Labat Deveaux, Vanessa Bloch, Nathalie Prince, Stéphane Mouly, Jean-Michel Scherrmann, Jean-Pierre Lépine, Jean-Louis Laplanche, Milou-Daniel Drici, Florence Vorspan

Journal, date & volume: Drug Alcohol Depend, 2014 Aug 1 , 141, 34-8

PubMed link: http://www.ncbi.nlm.nih.gov/pubmed/24875677

Abstract
Many drugs increase the duration of the QT interval of patients, potentially leading to harmful effects such as polymorphic ventricular arrhythmias. Most of these drugs do so by inhibiting the rapid component IKr of the delayed rectifier potassium current IK. Methadone is the most prescribed heroin maintenance treatment and is known to inhibit the cardiac potassium channel hERG, which recapitulates IKr. In order to evaluate if any polymorphism of potassium channels' genes could explain some of the "idiosyncratic" QT prolongations observed in patients treated with methadone, we tested the association between KCNE1, KCNE2, and KCNH2 polymorphism and the QT interval prolongation in those patients, controlling for other variables associated with a decrease of the repolarizing reserve.A cohort of 82 patients treated with stable dosage of methadone (mean dosage 65 mg/d) for at least three months was genotyped for five polymorphisms in KCNE1, KCNE2 and KCNH2 genes and had their corrected QT (QTc) assessed.The mean QTc interval was 415±34ms. In a linear regression model, longer QTc interval was associated with methadone dosage and with one genetic factor. Each copy of a Lys allele at codon 897 of KCNH2, the gene that encodes the cardiac potassium voltage-gated channel hERG, was associated with a 15.4ms longer QTc (95% CI [4.6-26.2]; p=0.001).KCNH2 genotyping may be relevant in the analysis of cumulative risk factors for QT prolongation in patients on methadone maintenance treatment.