BACKGROUND: Adherence to pharmacotherapy is crucial to prevent symptom deterioration in chronic diseases. However, non-adherence to chronic treatments is prevalent, especially in polypharmacy. Practical tools to assess adherence to polypharmacy in primary care are missing. AIMS: We aimed to develop an Adherence Monitoring Package (AMoPac) for general practitioners (GPs) to identify patient non-adherence. We tested the feasibility and acceptance of AMoPac in the primary healthcare setting. METHODS: AMoPac was developed based on peer-reviewed literature. It consists in (1) electronic monitoring of patients' medication intakes for 4 weeks, (2) receiving feedback on intake behaviour by the pharmacist and (3) generating an adherence report to communicate to the GPs. A feasibility study was conducted with heart failure patients. GPs' acceptance of AMoPac was explored with semistructured interviews. Electronic transmission of the reports into the GP's electronic health record along with laboratory reports stating N-terminal pro-B-type natriuretic peptide (NT-proBNP) levels was analysed. RESULTS: We developed AMoPac and tested its feasibility with six GPs and seven heart failure patients. GPs were satisfied with the adherence report including the pharmaceutical-clinical recommendations. Integrated transmission of adherence reports to GPs was not feasible due to technical incompatibilities. Mean taking adherence was 86.4%±12.8% and three patients had low correct dosing-days (69%, 38% and 36%, respectively). NT-proBNP ranged from 102 to 8561 pg/mL and four patients had elevated values (>1000 pg/mL). CONCLUSION: AMoPac is feasible in the primary healthcare setting, excluding the integrated transmission of adherence reports to GPs. The procedure was highly accepted by GPs and patients. AMoPac fills a gap by combining clinical values with adherence data, and therefore, delivers a multifaceted picture of the patient's behaviour. In case of unmet adherence, our tool might facilitate the selection of patient-centred approaches to optimise pharmacological therapies in chronic heart failure patients. TRIAL REGISTRATION NUMBER: NCT04326101.