The finding of a high prevalence of QTc prolongation in injection drug users receiving methadone reported by Ehret et al1 poses an important issue in the management of these patients because they found that this serious cardiac manifestation was independently associated with methadone use, the presence of cytochrome P-450 3A4 inhibitors, potassium level, and liver dysfunction. Many of these conditions are present in a large proportion of human immunodeficiency virus (HIV)-infected individuals, that is, injection drug users, virus-hepatitis–coinfected patients, people with alcohol abuse, and individuals receiving treatment with drugs that inhibit cytochrome P-450 3A4.
Petrosillo N, Lisena FP, Chinello P. QTc Prolongation in Human Immunodeficiency Virus–Infected Persons. Arch Intern Med. 2006;166(20):2288-2289. doi:10.1001/archinte.166.20.2288-c