Rational prescribing in geriatrics represents an important ethical as well as socio-economic issue. The aim of this project was to analyze the drug-related problems (DRPs) among the Czech nursing home residents and increase public awareness of further possible employment of clinical pharmacists in social care. The project was designed as a multicenter observational study. A total of 16 nursing homes and 800 participants with an average age of 84.6 ± 7.3 years were included in the study. Of them, a DRP was noted in 93.3% of people. The total amount of DRPs identified was 2215, which means an average of 2.8 ± 1.6 DRPs per patient. The most common DRPs identified were 'overtreatment' (19.5%), 'undertreatment' (12.8%), inappropriate dose (10.6%), recommendations for laboratory monitoring (10.4%) and adverse effects (10.3%). Of different drug classes, BZDs (OR 16.6, 95% CI 1.0-270.2), PPIs (OR 2.5, 95% CI 1.1-5.6) and NSAIDs (OR 4.4, 95% CI 1.1-18.3) were identified to be most commonly associated with DRPs. The risk of DRP identification clearly increased with the number of drugs used, with seven drugs demonstrated as the best cut-off for predicting DRP identification (AUC 0.842, sensitivity 0.602
specificity 0.796). 'SENIOR' project has confirmed a high rate of excessive polypharmacy among nursing home residents in the Czech republic resulting in high risk of potential and manifested DRPs. The project emphasized the role of clinical pharmacists in optimizing safety and effectiveness of treatment among older nursing home residents.