Long QT and torsade de pointes in a patient with acquired human immunodeficiency virus infection in multitherapy with drugs affecting cytochrome P450

In acquired human immunodeficiency virus (HIV) infection, a long depolarization period at ECG may be the consequence of cardiac complications due to viral myocarditis or cardiomyopathy or indirectly due to autonomic neuropathy, or sometimes resulting from pharmacological treatments. Several drugs administered for direct treatment of HIV disease or its complications, such as antiretrovirus, fluconazole, and antibiotics, may induce ventricular arrhythmias due to long QT prolonged depolarization period. Also methadone, frequently associated with HIV therapy to treat patients with opiate addiction, is described in the literature to have cardiac inotropic effects. It has also the potential to increase the QT period and to develop ventricular torsade de pointes, primarily through interference with the rapid component of the delayed rectifier potassium ion current. Moreover, the use of methadone associated with other inhibitors of cytochrome P450 might increase plasma concentrations and contribute to methadone cardiac toxicity. We report the case of an HIV patient receiving antiretroviral treatment, fluconazole and high-dose methadone, who suddenly complained of vertigo, dizziness, pre-syncope and syncope due to severe ventricular arrhythmias that disappeared after discontinuation of all treatments.