RESUMEN
BACKGROUND: Despite the evidence of benefits, clinical pharmacy services (CPS) are not uniformly implemented across healthcare institutions. Understanding the influencing factors and identifying the domains in which they act is the first step to a successful implementation. OBJECTIVE: To identify the factors that affect the implementation of CPS for inpatients and to categorize them. METHODS: Cochrane Library, Embase, CINAHL, IPA, Medline/PubMed, and Lilacs databases were researched up until January 2018. The search strategy was developed using text words or MESH terms related to the following four domains: "clinical pharmacy," "influencing factors," "implementation," and "hospital." Two reviewers selected original research articles that reported the factors influencing the implementation of CPS in hospitals, extracted data, and assessed the quality of the studies. After framework synthesis and categorization of the factors, a diagrammatic approach was used to present the results. RESULTS: Fifty-three factors were identified in the 21 studies that were included in this review. The most cited influencing factors were uniformly distributed across the following four domains: Attitudinal, POlitical, TEChnical and Administrative (APOTECA domains). However, in terms of level (pharmacist, healthcare team, patient, institution, and national organization), the "pharmacist" group had the highest concentration of factors. "Clinical skills and knowledge" was the most frequently cited implementation factor, followed by "time to implement CPS." CONCLUSION: Our findings showed the multifactorial nature of CPS implementation process. We suggest that factors from all four APOTECA domains need to be fully considered and strategies need to be addressed for all five groups of interest to successfully implement CPS in hospitals. Future studies on the influence of implementation stages, interrelationships of implementing factors, and strategies to overcome barriers could accelerate the successful adoption of these services. REGISTRATION: PROSPERO register CRD42016050140.