Objectives People living with HIV (PLWH) are common users of complementary and alternative medicine (CAM). The main objective of this study was to study the frequency and patterns of CAM natural products use in a large cohort of PLWH and to identify potential drug–drug interactions (DDIs) and the impact on their antiretroviral treatment (ART) adherence and efficacy.

Methods This was a cross-sectional multicenter survey including 420 PLWH from different Spanish hospitals. Participants completed a face-to-face questionnaire on CAM consumption and different sociodemographic and clinical data were collected. DDIs between CAM and ART were identified and classified according to the Liverpool University Database and patient factors related to CAM consumption were assessed.

Results 420 participants were included (82.6% male, mean age 47 years); 209 patients (49.8%) were taking at least one CAM. The most consumed CAM were green, black and red tea (n=146, 25.4%), ginger (n=26, 4.5%), fish oil (n=25, 4.4%) and cannabis (n=24, 4.2%). An ART based on integrase inhibitors was the only factor independently associated with CAM consumption (OR 1.54, 95% CI 1.04 to 2.26). 50 potential CAM–ART interactions in 43 (20.6%) patients taking CAM were identified, being clinically significant in 80% of the cases. CAM products most frequently involved with a potential significant DDI were supplements containing divalent cations (n=11) and garlic (n=7). No differences in ART efficacy and adherence were observed between patients with and without CAM consumption.

Conclusions Almost 50% of patients were taking at least one CAM product and its use was associated with an integrase inhibitor based ART. One out of every six patients was at risk of presenting with an interaction between a CAM and their ART, confirming the need to review continuously the use of CAM as part of the medication review process.