Antiretroviral drug interactions decline, but clinical screening for drug interactions remains important

posted on July 27, 2022

Pharmacovigilance Initiative Principal Investigator Dr. Rolando Barrios and Research Coordinator Ms. Kathy Lepik

New BC-CfE research, published in the recent issue of AIDS, characterizes trends in the annual prevalence of drug interactions between antiretroviral therapy (ART) and other non-antiretroviral medications in relation to ART prescribing patterns. The study also describes drug interaction-related ART changes.

Titled, “Evolving patterns of antiretroviral drug interactions in people with HIV in British Columbia, Canada,” this cohort study included persons living with HIV (PLWH) who received ART through the BC-CfE Drug Treatment Program (DTP) between 2010 and 2016. The research analyzed medication dispensing records from the BC-CfE’s Seek And Treat For Optimal Prevention Of HIV/AIDS (STOP HIV/AIDS) population-based, linked administrative-health dataset, designed to support BC’s Treatment as Prevention activities. Clinician-reported drug interaction-related ART changes were also summarized using records from the BC-CfE Pharmacovigilance Initiative, which monitors ART safety in DTP participants.

The study included 8,571 PLWH who received both ART and non-antiretroviral medications. Researchers found that the proportion of ART-treated PLWH having at least one drug interaction significantly declined from 85% in 2010 to 71% in 2016. The proportion with a non-recommended (“avoid”) drug combination also fell from 5.6% to 3.2% during this time period.

The authors observed that the downward trend in drug interaction prevalence paralleled the declining use of ART regimens with higher drug interaction potential (e.g. ritonavir or cobicistat-boosted protease inhibitors, and hepatic enzyme inducers such as efavirenz or nevirapine) and increasing use of ART with lower drug interaction potential (e.g. unboosted integrase inhibitors such as dolutegravir). The researchers found the overall adjusted risk of receiving a non-recommended combination of ART and non-antiretroviral drugs was three times higher for persons taking antiretrovirals with higher drug interaction potential versus those receiving lower drug interaction-risk ART.

Reports of drug interaction-related ART changes received by the Pharmacovigilance Initiative also mainly involved interactions with ritonavir or cobicistat-boosted protease inhibitors. In particular, drug interactions between the “boosted” ART and inhaled corticosteroids such as fluticasone (used to treat asthma and allergies) were observed throughout the study period and were associated with adverse events including adrenal suppression.

The authors concluded that although the occurrence of ART-related drug interactions is declining as ART prescribing shifts towards antiretrovirals with lower drug interaction potential, potentially harmful, non-recommended drug combinations remain a concern. They caution healthcare providers to screen for drug interactions each time new ART or non-antiretroviral medications are prescribed or dispensed.

Newer antiretrovirals have relatively lower risk for drug interactions compared to older HIV medications, but remember: Always check for possible antiretroviral drug interactions before taking any medicine or supplement.
- Pharmacist Kathy Lepik, Research Coordinator of the BC-CfE Pharmacovigilance Initiative, and project lead for this study

BC Centre for Excellence in HIV/AIDS

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Antiretroviral drug interactions decline, but clinical screening for drug interactions remains important

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