Background The effectiveness of antiretroviral treatment depends on several factors. Incorrect adherence is the main cause of treatment failure and it has been related to an increase in mortality.

Purpose To assess the compatibility of the recommendations for antiretroviral treatment administration with the recommendations in the product information. To discover the patients' adherence to the treatment.

Materials and methods Prospective observational study, conducted over two weeks, in an outpatient pharmacy department of a community hospital that serves a total of 415 HIV patients. All the HIV patients that came to collect their treatment in the pharmacy department and agreed to collaborate in the study were included. The exclusion criteria were: patients who started or changed their treatment, if it was a relative who collected the treatment or because of a language barrier. A data collection sheet was designed, which included demographic information (gender, age), data related to antiretroviral therapy (which drugs, how and when they were taken) and the SMAQ (Simplified Medication Adherence Questionnaire) adherence test.

Results 112 patients were interviewed. 76 of them were included in the study (78.95% (60) men, mean age 48). 40.80% (31) of patients did not follow the product information recommendations. The drugs with which more discrepancies were found were ritonavir (14.47%; 11) and efavirenz (17.11%; 13). Ritonavir was mainly taken on an empty stomach instead of being taken with meals. Efavirenz was taken with meals instead of being taken on an empty stomach as recommended in the product information. 39.47% (30) of patients were considered non-adherent according to the SMAQ adherence test.

Conclusions These results confirm the need to include a pharmaceutical care programs for HIV patients. It would be advisable to inform them about their treatment prior to them starting it to achieve the maximum benefit and to improve the adherence to the treatment. Future studies with other adherence tests would be interesting in order to compare the results.