Management of polypharmacy and potential drug-drug interactions in people with HIV and cancer: insights from a 4-year multidisciplinary clinic experience

Background: People with HIV and cancer (PWHC) are often treated with different combinations of antiretroviral and oncology drugs, frequently associated with other co-medications; this significantly increases the risk of potential drug-drug interactions (DDIs). Research design and methods: A prospective observational study has been carried out from May 2020 to May 2024 to describe the management of therapies in PWHC in an outpatient clinic. Results: 140 PWHC treated with 42 different antiretroviral and 59 oncology regimens were enrolled, resulting in the identification of 410 DDIs. Of these, 8% were scored as red-flag DDIs). Among antiretroviral medications, 77% of red-flag DDIs involved ritonavir or cobicistat. Paclitaxel was the oncology drug most frequently associated with red-flag-DDIs (77%). Proton pump inhibitors (PPIs) were involved in 19% of red-flag and 32 of orange-flag DDIs. The most frequent recommendations included performing an electrocardiogram (38%), conducting therapeutic drug monitoring (31%), discontinuing PPIs (29%) and/or adjusting the timing of drug intake (28%). Conclusions: A high prevalence of polypharmacy and clinically relevant DDIs was observed in our cohort of PWHC. A multidisciplinary team could play a pivotal role in optimizing pharmacological therapies in this clinical setting, for example, by reducing the use of PPIs and booster-based antiretroviral regimens.