Prevalence of potential drug-drug interactions (PDDIs) between antiretroviral drugs (ARVs) and comedications was high in 2008 in a Swiss HIV Cohort Study (SHCS) survey. We reassessed the prevalence of PDDIs in the era of HIV integrase inhibitors (INIs), characterized by more favorable interaction profiles.
The prevalence of PDDIs in treated HIV positive individuals was assessed for the period: 01-12/2018 by linkage of the Liverpool HIV drug interactions and SHCS databases. PDDIs were categorized as harmful (red flagged), of potential clinical relevance (amber flagged) or of weak clinical significance (yellow flagged).
In 9’298 included individuals, median age was 51 years (IQR 43; 58), and 72% were males. Individuals received unboosted INIs (40%), boosted ARVs (30%), and non-nucleoside reverse transcriptase inhibitors (NNRTIs) (32%) based regimens. In the entire cohort, 68% received > 1 comedication, 14% had polypharmacy (> 5 comedications) and 29% had > 1 PDDI. Among individuals with comedication, the prevalence of combined amber and yellow PDDIs was 43% (33% amber – mostly with cardiovascular drugs – and 20% yellow flagged PDDIs) compared to 59% in 2008. Two percent had red flagged PDDIs (mostly with corticosteroids), the same as in the 2008 survey. Compared to 2008, fewer individuals received boosted ARVs (-24%) and NNRTIs (-13%) but the use of comedications was higher.
Prevalence of PDDIs was lower with more widespread use of INIs in 2018 than in 2008. Continued use of boosted regimens and increasing needs for comedications in this aging population impeded lower rates of PDDIs.

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