Methadone dose , presence of cytochrome P-450 3A4 inhibitors , potassium level , and liver function contribute to QT prolongation .
B-ChemicalEntity O O O O B-ChemicalEntity I-ChemicalEntity I-ChemicalEntity I-ChemicalEntity O B-ChemicalEntity O O O O O O O B-DiseaseOrPhenotypicFeature I-DiseaseOrPhenotypicFeature O