Atazanavir-Associated QT Interval Prolongation and Torsades de Points in a Patient With Liver Cirrhosis: A Rare But Serious Complication

Monomorphic ventricular tachycardia due to protease inhibitor intoxication by atazanavir

Atazanavir is a protease inhibitor approved for use in combination with other antiretroviral drugs for the treatment of human immunodeficiency virus infection. Atazanavir and other protease inhibitors can sometimes induce corrected QT prolongation and ventricular arrhythmia. A 40-year-old man with no comorbidities, except human immunodeficiency virus 1 infection, presented with palpitations 3 days after an overdose of 150 caps of atazanavir, with suicidal intent. His initial electrocardiogram showed monomorphic ventricular tachycardia, and hyperbilirubinemia was observed in his initial blood test. Immediately after magnesium sulfate infusion, his ventricular tachycardia was converted into junctional bradycardia with prolonged corrected QT. After 3 days of close observation in the intensive care unit, the corrected QT prolongation and hyperbilirubinemia were normalized.

Associated factors of drug-drug interactions of highly active antiretroviral therapy: report from a referral center

OBJECTIVE

To assess different aspects of potential drug-drug interactions (DDIs) including incidence, severity, level of evidence and probable associated factors in Iranian HIV-infected individuals receiving antiretroviral therapy.

METHODS

All adult HIV-infected patients under highly active antiretroviral therapy regimen attending a referral HIV clinic during 1 year were screened retrospectively for potential moderate or severe DDIs by the Lexi-Interact On-Desktop software.

RESULTS

Near seventy percent (69.89%) of detected DDIs in our population were major. The three most common detected potential DDIs were efavirenz + methadone (11 cases), lopinavir-ritonavir + sulfamethoxazole-trimethoprim, (10 cases) and lamivudine + ribavirin (7 cases). Lopinavir-ritonavir (27.96%) and citalopram (23.66%) were the most common offending antiretroviral and non-antiretroviral agents, respectively.

CONCLUSION

Performing multicenter and prospective studies is warranted to assess the real clinical as well as economic impacts of DDIs on HIV-infected patients receiving antiretroviral agents in our population and also to develop efficient preventive strategies.

Protease inhibitor-associated QT interval prolongation

OBJECTIVE

To evaluate the literature on protease inhibitor (PI)-associated QT interval prolongation and risk for torsade de pointes in patients infected by HIV.

DATA SOURCES

Primary literature was identified through MEDLINE (1950-August 2011) and EMBASE (1980-August 2011), using the following search terms: antiretroviral agents, HIV, protease inhibitors, QTc, QT prolongation, and torsade de pointes.

STUDY SELECTION AND DATA EXTRACTION

English-language case reports of antiretroviral therapy-associated QT interval prolongation, studies of healthy volunteers, or studies that evaluated the impact of PIs on QT interval in patients infected with HIV were reviewed and selected. Article bibliographies and conference abstracts were also reviewed.

DATA SYNTHESIS

Several case reports, as well as in vitro data, have implicated PIs as a potential cause of QT interval prolongation and/or torsade de pointes. Saquinavir, therapeutically boosted with the potent CYP3A4 inhibitor ritonavir, was the only PI shown to be associated with significant QT interval prolongation in studies with healthy volunteers. While 1 case control study in HIV-infected patients found that nelfinavir or efavirenz, a nonnucleoside reverse transcriptase inhibitor, increased the risk of QT interval prolongation, larger prospective studies have not demonstrated any significant increase in QT interval following exposure to PIs. Similar risk factors for QT interval prolongation seen in non-HIV-infected patients, such as older age, female sex, ethnicity, cardiac conditions, diabetes mellitus, and concomitant use of other QT interval-prolonging medications, especially methadone, were risk factors identified in studies of HIV-infected patients.

CONCLUSIONS

PIs do not appear to independently predispose patients to QT interval prolongation. However, other risk factors (both HIV-related and non-HIV-related) may increase the risk of QT interval prolongation. Available data suggest that baseline and follow-up electrocardiogram monitoring are unnecessary precautions, but may be considered in patients who are initiating PI therapy and are on multiple medications with proarrhythmic potential and/or have multiple comorbidities, increasing the risk.