Background and Importance Polymedication has potential health risks for patients such as interactions and increased risk of adverse effects that can be fatal.

Aim and Objectives The aim of this study was to analyse a pharmaceutical intervention carried out by a group of pharmacists in patients taking 15 or more drugs concomitantly to improve the safety and adequacy of their prescriptions.

Material and Methods Pre-post study that included patients of any age, with 15 or more drug prescriptions, prescribed by a general practitoners (GPs) in the electronic prescription system, from January to December 2021. The intervention was performed by 9 pharmacists in 35 primary health-care centres (PHCC) and 673 GPs. They provide health care to 677,782 inhabitants. First, a general session was held in each PHCC, presenting the objectives and informative material. Subsequently, individual meetings were scheduled with each physician, in which the pharmacists provided the prescribers with lists of polymedicated patients (PP) and various local documents, STOPP/START, Beers criteria and clinical practice guidelines to help review treatments. Each prescribed drug was evaluated based on its necessity, effectiveness, appropriateness and safety. In addition, the pharmacists also issued review reports on patients with particularly complex pathologies. The reviews performed were recorded by the GPs in the digital health record. These records and lists of PP were extracted thanks to a local software application and analysed in Excel.

Results Pharmacists provided 39 group training sessions and 387 individual meetings to the Gps. A total of 1468 patients met the criteria for PP. Mean age 73.58 years+-11.14(58%women). Prescriptions of 91.7%of PP were reviewed at least once in 2021. A total of 4,848 reviews were performed.

In 14.41%of the cases, a new treatment was started. In 14.73%of the revisions, it was necessary to change the dosage or the prescribed treatment regimen. In 27.81%of the cases, the GPs cancelled a drug from the patient´s prescriptions. In 54.68%of the reviews, no change in treatment was made

Conclusion and Relevance The intervention had a high level of acceptance.

Despite the high percentage of patients reviewed, it is striking the high number of patients in whom, no change in their treatment was made, which raises the question of whether the reviews were correct.

Conflict of Interest No conflict of interest