Objectives Avoiding harm when patients interact with healthcare services is a global issue. Guidelines are often produced to improve the prescribing and monitoring of medication with a narrow therapeutic index. Adherence to guidelines may not occur in clinical practice. This paper aims to explore the barriers faced by clinical pharmacists and junior doctors when using complex guidelines to support the prescribing and therapeutic drug monitoring of gentamicin and vancomycin.

Methods Twenty-three junior doctors and 27 clinical pharmacists took part in focus groups at four hospital sites in four Scottish health boards between March and July 2011. Focus groups were run separately at each hospital site for the two clinical groups. The data were organised using the framework approach, validated, and a thematic analysis was conducted.

Results Five themes emerged to explain barriers to effective initial prescribing and therapeutic drug monitoring, which were divided into two types. Barriers could be a direct result of the content of the guidelines—specifically that clinicians required experience to use the guidelines effectively. Barriers also resulted from a failure in the context in which the guidelines function which was related to insufficient dissemination, communication issues within the hospital site, unmet educational needs and staffing issues.

Conclusions Improved patient safety cannot be assumed due to the existence of gentamicin and vancomycin guidelines. The findings of this study highlight the complexities associated with their appropriate use. Future quality improvement strategies must consider where the guidelines will be implemented, and the context in which they will function.