Background and importance Integrase inhibitors (raltegravir, dolutegravir, elvitegravir, bictegravir and cabotegravir) should be administered 2 hours before or 6 hours after taking medications containing polyvalent cations, such as antacids or multivitamins. Simultaneous coadministration of integrase inhibitors and polyvalent cations contained in antacids or vitamin supplements results in their reduced absorption due to a chelation process.

Aim and objectives To analyse the effectiveness of a pharmaceutical intervention to prevent the potential interaction between integrase inhibitors and vitamin supplements or antacids.

Material and methods Retrospective study conducted between May and September 2021. Patients were included if they were on treatment with ART containing an integrase inhibitor, both naive and continuation, and if they attended the pharmacy outpatient service during the study period.

Demographic (sex and age) and pharmacological variables were collected. It was also documented whether patients were taking their treatment adequately and, if not, whether they were committed to modifying their medication management.

Results One hundred and thirty-five patients treated with antiretroviral therapy (ART) containing raltegravir, dolutegravir, elvitegravir, bictegravir or cabotegravir were interviewed. Mean age was 47 years and 72% were men.

33% of the patients confirmed that they took a multivitamin and mineral complex daily and 21% took antacids occasionally.

Pharmaceutical advice was given to these patients using infographics to help them understand how to take their treatments properly (taking ART 2 hours before or 6 hours after multivitamins or antacids). 80% of these patients were not taking their therapy properly due to lack of information and 100% of them committed to following the pharmaceutical advice in order to improve the effectiveness of their treatment.

Two months later, the counselled patients were contacted by telephone and 92% confirmed that they were following the pharmacist’s recommended guidelines. The remaining 8% could not be contacted.

Conclusion and relevance This study shows a large population that takes non-prescription drugs and is uninformed. Patients should be adequately interviewed during dispensing of treatment to find out what other non-prescription medicines they are taking in order to effectively prevent drug-drug interactions and to optimise ART.

Conflict of interest No conflict of interest