["To describe variations in nurses' perceptions of using a computerised decision support system (CDSS) in drug monitoring.", "There is an increasing focus on incorporating informatics into registered nurses' (RNs) clinical practice. Insight into RNs' perceptions of using a CDSS in drug monitoring can provide a basis for further development of safer practices in drug management.", 'A qualitative interview study of 16 RNs. Data were analysed using a phenomenographic approach.', "The RNs perceived a variety of aspects of using a CDSS in drug monitoring. Aspects of 'time' were evident, as was giving a 'standardisation' to the clinical work. There were perceptions of effects of obtained knowledge and 'evidence' and the division of 'responsibilities' between RNs and physicians of using the CDSS."] Does nurses ' use of computerised decision support systems affect drug monitoring in nursing homes?