Table 3 Reported barriers to acceptance of the pilot Therapeutic Drug Monitoring Advisory Service (the Service) aligned with the domains of the Theoretical Domains Framework (TDF)

‘Knowledge’

Lack of procedural knowledge

“… so I might know that actually it [trough concentration] was a peak, or actually it was taken before the wrong dose or I might just know that from being on the ward and realise that there was a mistake there, so if I’m given advice based on that mistake then I wouldn’t” (P03, JMO)^a

“There are times when the blood is not actually taken at an appropriate time … that’s the only time I can think of, when I know there’s a problem with the test … so when there’s something I’m aware of, that the person who’s just looking at numbers on the computer is not aware of” (P13, Registrar)^a

Lack of knowledge of the existence of the Service

“I guess [a] major limitation would be people not knowing about it” (P06, Pharmacist)

“… if people are moving around from different hospitals and don’t train early on knowing that this is available...” (P09, Registrar)

Lack of scientific knowledge

NR

“I guess the lack of evidence, again, coming back to the same point, and perhaps even clinical guidelines … some people may prefer to refer to the guidelines because a lot of work has gone into it; a lot of evidence from other sources” (P17, Pharmacist)^a

‘Environmental Context and Resources’

Limited accessibility of dose advice

“The turnaround time of these reports might be a limitation … are they available when we need them?” (P21, Pharmacist)

“… the hours in which it runs … but it probably won’t be running on the weekend, so as long as there’s another something in place” (P04, JMO)

Communication issues

NR

“… the only way of potentially complicating it I think is communication issues” (P09, Registrar)

Resources, person x environment

NR

“… it depends how busy the person is, I mean if they’re on the team that has a lot of patients then electronically, they may or may not forget” (P14, JMO)

‘Social Influences’

The prescribing hierarchy

“… sometimes I’ve been asked to not chart the medication that is being prescribed, and that’s come from either ID or from one of our senior registrars and I think it’s because of the clinical picture of the patient that they’ve decided to go with the current dose” (P08, JMO)

“If it was a complex patient, we’d probably get an infectious diseases consult and then they could give advice as to what to do with that recommendation” (P10, JMO ^a

‘Beliefs about Consequences’

Belief that dose advice is incorrect

“… perhaps if the recommended dose was very much different to what they thought it would be and what consultants might want as well, that would be a large barrier in terms of accepting and adopting that change” (P11, Pharmacist)^a

“… if it was abnormally high or there was something that didn’t make sense. If I had seen they were previously quite stable and then it suddenly said, ‘Triple the dose’, then that would be a bit odd and you’d probably want to question.” (P20, Registrar)^a

Increased workload

NR

“… the only time I guess it could be hard to accept it is if, for example, in oncology and haematology patients when they lose weight really quickly over a week or two and that might not be updated on the [hospital electronic medication management system], so it might not represent the true weight and then you’d have to sort of manually check it to make sure that it’s all fine” (P12, JMO)^a

Belief that dose advice will not be accessed

“… there’s no guarantee that anyone will look at this So I suppose it’s on assumption that, you know, this information is available and prescribers and healthcare workers will look into it, or make use of it” (P19 Registrar)

NR

Concerns that dose advice is not appropriate

NR

“Broadly speaking, where I would you know have concerns it’s too high or low, their renal function’s gone off since the dose recommendation had been made but I doubt there’d be too much in it” (P23, Staff Specialist)

‘Social/Professional Role and Identity’

Role of senior clinicians in prescribing decision-making

NR

“I could imagine sometimes, you know, the consultants in a certain setting might disagree with it” (P23, Staff Specialist)

‘Skills’

Deskilling of healthcare professionals

“I think it does take away your own learning process … I used to know by heart what the values were that I should be aiming for. Whereas now I feel like I’m becoming a bit more dependent on the system telling me what to do” (P08, JMO)

“I think the one [limitation] I foresee is that it will lead to a degree of deskilling, which is a problem you get with any process you introduce.” (P13, Registrar)

‘Memory, Attention and Decision Processes’

Forgetting to check dose advice

NR

“… you have to remember to actually look up the result online” (P12, JMO)