Abstract
Background
Potential drug–drug interactions (PDDIs) might expand with new combination antiretroviral therapies (ART) and polypharmacy related to increasing age and comorbidities. We investigated the prevalence of comedications and PDDIs within a large HIV cohort, and their effect on ART efficacy and tolerability.
Methods
All medications were prospectively recorded in 1,497 ART-treated patients and screened for PDDIs using a customized version of the Liverpool drug interactions database.
Results
Overall, 68% (1,013/1,497) of patients had a comedication and 40% (599/1,497) had ≥1 PDDI. Among patients with comedication, 2% (21/1,013) had red-fag interactions (contraindicated) and 59% (597/1,013) had orange-fag interactions (potential dose adjustment and/ or close monitoring required). The latter involved mainly central nervous system drugs (49%), cardiovascular drugs (34%) and methadone (19%). In the multivariate analysis, factors associated with having a comedication were advanced age, female gender, obesity and HCV infection. Independent risk factors for PDDIs were regimens combining protease inhibitors and non-nucleoside reverse transcriptase inhibitors (odds ratio [OR] 3.06, 95% confidence interval [CI] 1.44–6.48), ≥2 comedications (OR 1.89, 95% CI 1.32–2.70), current illicit drug use (OR 2.00, 95% CI 1.29–3.10) and patients with HCV infection (OR 1.74, 95% CI 1.19–2.56). Viral response was similar in patients with and without PDDIs (84.5% versus 86.4%; P=0.386). During follow-up, ART was modified in 134 patients with comedication regardless of the presence of PDDIs (P=0.524).
Conclusions
PDDIs increase with complex ART and comorbidities. No adverse effect was noted on ART efficacy or tolerability; however, most PDDIs affected comedication but were manageable through dose adjustment or monitoring.