Drug treatment in elderly patients is a challenge for healthcare systems. This challenge is exacerbated by age-related changes in pharmacokinetics and pharmacodynamics, multimorbidity, frailty and cognitive impairment. Moreover, old patients are commonly exposed to polypharmacy, leading to increased risk of drug interactions, adverse drug reactions, and higher costs for the healthcare systems. Thus, the complex task of prescribing medications to older polymedicated patients encourages the use of Clinical Decision Support Systems (CDSS). This paper evaluates the CDSS miniQ for identifying potentially inappropriate prescribing in older adults with polypharmacy and to assesses the usability and acceptability of miniQ in health care professionals, patients, and caregivers. It describes how useful is CDSS miniQ system for Primary Care physicians, as well as for patients and their caregivers to know their medications. The discussion emphasizes how this system is useful to improve the prescribing process and reduce errors.