[Prevalence of potential drug-drug interactions involving antiretroviral drugs in Buenos Aires, Argentina].

Introduction: Antiretroviral agents (ARVs) have a high potential for drug interactions. However, the prevalence and risk factors for clinically significant drug-drug interactions (CSDDIs) with ARVs from Latin American countries is unknown.

Aim: To evaluate the prevalence and risk factors for CSDDIs in HIV outpatients attending at two centers in Buenos Aires, Argentina.

Methods: Descriptive cross-sectional study (september to november 2012). HIV-1 infected patients under ARV treatment at the time of the study were randomly assessed for concomitant medication. CSDDIs were screened using the University of Liverpool Drug Interactions Program (www.hiv-druginteractions.org).

Results: A total of 217 patients were included. Male sex: 64% (CI 95: 57-70). Median age (IQR): 41 (36-48). Presence of comorbidities: 19%. ARV regimen: NNRTI-based: 48%, PI-based: 50% and NNRTI plus PI: 2%. Median of CD4 T-cell count (IQR): 402 cells/mL (235-588). Viral load < 50 copies/mL: 78%. Overall, 64% (CI 95: 57-70) of patients had > 1 co-medication of whom a 49% had at least one CSDDI. Two patients had a CSDDI between ARVs. The most frequent co-medications observed were antimicrobial (40%), cardiovascular (25%) and gastrointestinal agents (22%). In the multivariate analysis the number of co-medications and use of CNS agents were associated with the presence of CSDDIs.

Conclusions: Co-medications and CSDDIs were common in our setting. In this context, training of HIV physicians in drug interactions is of major importance for adequate management of these patients.