Concomitant use of gastric acid-reducing agents is frequent among HIV-1-infected patients receiving protease inhibitor-based highly active antiretroviral therapy.

Objective The aim of the study was to assess the frequency of the concurrent use of gastric acid-reducing agents among HIV-1-infected patients treated with highly active antiretroviral therapy (HAART) combinations. Methods An anonymous, semistructured, self-administered questionnaire was consecutively distributed among HIV-1-infected patients at routine visits to specialized HIV clinics. The questionnaire contained 17 items asking specifically for information on current antiretroviral treatments and the use of gastric acid-reducing agents as well as demographic data. Results A total of 424 patients in 12 centres participated in the study: 85% were male, 88% were of German nationality, 82% were > 35 years of age and 201 (47.4%) were receiving a protease inhibitor (PI)-containing HAART regimen. Of these, 74 (37%) had received an acid-reducing drug within the previous 6 months and 43 (58%) were currently still on it. Two-thirds of patients (64.9%) were treated with proton-pump inhibitors (pantoprazole, omeprazole or esomeprazole) and 56% of patients on PI-containing regimens had been taking these drugs for longer than 2 months and up to a maximum of 3 years. The majority of patients (77%) had received the prescription for the acid-reducing drugs from their HIV specialist and the remaining patients had received over the counter (OTC) medication or prescriptions from other medical personnel. Conclusions A substantial subset of patients treated with HAART combinations, including those on PI-containing regimens, were using concomitant acid-reducing drugs, most often proton-pump inhibitors. As negative drug-drug interactions between some of the (boosted) PIs and gastric acid-reducing agents have recently been reported, HIV physicians should take this into account when prescribing PI-containing HAART combinations in order to avoid an additional risk of treatment failure.