Prevalence of drug-drug interactions in the era of HIV integrase inhibitors: a retrospective clinical study.

BACKGROUND Antiretroviral agents pose a high risk for drug-drug interactions (DDIs), mainly but not limited to being a substrate, inducer or inhibitor of P450 cytochrome enzymes. In part metabolised by other pathways, integrase inhibitors might show a more favourable profile. The aim of this study was to investigate the prevalence of DDIs in daily clinical practice for patients starting different antiretroviral treatment (ART) regimens. METHODS All patients starting ART in our centre from January 2009 to April 2016 were included. All prescribed co-medications since the start of ART were recorded retrospectively from the medical files and screened for DDIs using the Liverpool HIV drug interaction database. Only DDIs between antiretroviral and non-antiretroviral drugs were considered. RESULTS We included 145 patients, of which 42% were on an integrase inhibitor-based regimen, mainly dolutegravir and elvitegravir. Of the patients, 78% (n = 113) took co-medication. Potential DDIs were seen in 63% of the patients with co-medication; contraindicated prescriptions were detected in 1%. Protease inhibitor-based ART was a risk factor for DDI (odds ratio (OR) 2.57; 95% confidence interval (CI) 1.06-6.19), in contrast to non-nucleoside reverse transcriptase inhibitor-based ART (OR 0.77; 95% CI 0.32-1.84). Concerning integrase inhibitors, a significantly lower risk was seen with dolutegravir-based treatment (OR 0.35; 95% CI 0.15-0.82), though not for elvitegravir-based ART (OR 2.51; 95% CI 0.66-9.58). CONCLUSIONS ART regimens pose a dissimilar risk for drug-drug interactions in clinical practice. Regarding the use of integrase inhibitors, a significantly lower risk was seen with dolutegravir-based treatment.