Map of use of parenteral analgesic admixtures in Spain. MEDPAIN project. / Mapa de utilización de mezclas analgésicas por vía parenteral en España. Proyecto MEDPAIN.

OBJETIVE: This study is the first part of the MEDPAIN project "Update of analgesic parenteral admixtures: studies of use, compatibility and stability", and its goal is to develop a national map about the use of analgesic parenteral admixtures in healthcare settings. METHODS: Observational study, based on a survey aimed at Spanish hospital pharmacists, during the period December 2020-April 2021. The questionnaire was designed in the RedCap® platform and disseminated through the Spanish Society of Hospital Pharmacy distribution list. An analgesic parenteral admixture (AM) was defined as the combination of two or more drugs, with at least one of them being an analgesic. The same combination of active ingredients, at different concentration and/or administered by different routes, was considered as a unique AM in this study. Some registered endpoints were related to the characteristics of the healthcare settings participating in the study, and others were related to the AM, such as drugs, doses and concentration range, route of administration, frequency of use, indication and type of patient (adult/pediatric) and where they are prepared. RESULTS: A total of 67 valid surveys from healthcare settings of 13 Spanish Autonomous Communities were received. They reported 462 AM. Every healthcare center informed an average of 6 AM (ICR p25-p75 =4.0-9.0). Most of the reported mixtures were used in adults (93.9%) at hospital settings (91.8%), and they were mostly protocolized and frequently used. The 21.4% of them were compounded at the Pharmacy service. The AM included 26 different drugs, with opioid analgesics being present at the 87.4% of them. Midazolam was the most usual adjuvant drug. According to the definition of AM in this study, there were finally 137 different combinations mainly with two drugs (40.6%), but also with three (37.7%), four (15.2%) and five ingredients (6.5%). CONCLUSION: This study reveals the wide variability in current clinical practice and shows which are the most used analgesic parenteral admixtures in our country.