Prescribers’ views and experiences of assessing the appropriateness of prescribed medications in a specialist addiction service
Prescribers' views and experiences of assessing the appropriateness of prescribed medications in a specialist addiction service
Adejoke Obirenjeyi Oluyase 0 1 2 3
Duncan Raistrick 0 1 3
Elizabeth Hughes 0 1 3
Charlie Lloyd 0 1 2 3
0 Leeds and York Partnership NHS Foundation Trust
1 School of Health and Human Sciences, University of Huddersfield , Harold Wilson Building, Queensgate, Huddersfield HD1 3DH , UK
2 9 Springfield Mount , Leeds LS2 9NG , UK
3 Department of Health Sciences, University of York , Room 208b, Area 4 ARRC Building, Heslington, York YO10 5DD , UK
4 Adejoke Obirenjeyi Oluyase
Background Mental and physical health problems are common in people with substance misuse problems and medications are often required in their management. Given the extent of prescribing for service users who attend specialist addiction services, it is important to consider how prescribers in this setting assess the appropriateness of service users' prescribed medications. Objective To explore prescribers' views and experiences of assessing the appropriateness of medications prescribed for service users coming in for treatment as well as the differences between prescribers. Setting A specialist addiction service in the North of England. Method A phenomenological approach was adopted. Semi-structured interviews were conducted with four nurse prescribers and eight doctors. Data were analysed using thematic framework analysis. Main outcome measure Prescribers' views and experiences of assessing the appropriateness of prescribed medications. Results Assessment of the appropriateness of prescribed medications involved reviewing medications, assessing risk, history-taking, involvement of service users, and comparing guideline adherence and 'successful' prescribing. Doctors and nurse prescribers assessed the appropriateness of medications they considered to be within their competency. Doctors provided support to nurse prescribers and general practitioners (GPs) when dealing with issues around prescribing. Conclusion Assessment of the appropriateness of prescribed medications is complex. The recent reduction in medical expertise in specialist addiction services may negatively impact on the clinical management of service users. It appears that there is a need for further training of nurse prescribers and GPs so they can provide optimal care to service users.
Appropriateness; Medications; Medical prescribers; Nurse prescribers; Specialist addiction service; United Kingdom
• Nurse prescribers and doctors in a specialist addiction
service differ in the types of medications they review but
appear to be working within their competency.
• Decreasing medical expertise in addictions may pose a
threat to quality decision-making by nurse prescribers.
• The decreasing availability of medical expertise in
addiction services presents a challenge to the management of
complex service users by GPs.
• There is a need to provide training and support to nurse
prescribers and GPs on prescribing for people with
substance misuse problems, so that they can provide optimal
care to specialist addiction service users.
People with substance misuse problems often have
co-existing physical and/or mental health conditions [
], and are
prescribed a large number of medications which may
sometimes not be justified . Service users who seek treatment
in specialist addiction clinics are more likely to have higher
levels of dependence and complex needs that include social
problems, functional impairment, comorbidities and use of
multiple medications when compared with those who do not
seek help [
]. These complex needs may influence
prescribing decisions made for this population . For instance,
prescribing may be targeted at maintaining equilibrium in
the lives of service users, which may lead to prescribing
outside of guideline recommendations. Furthermore,
service users may want certain medications such as opioids and
benzodiazepines prescribed for non-medical reasons [
Opioids used in pain treatment and benzodiazepines for
mental health problems have been implicated in the
occurrence of adverse events in people with substance misuse
problems. Benzodiazepines, antidepressants, antipsychotics
and substances such as alcohol have often been found to be
used in combination with opioids such as dihydrocodeine
and oxycodone in opioid-related overdose and fatalities
]. Antidepressant prescriptions, especially tricyclic
antidepressants (hereafter TCAs), have also been linked to
heroin overdose [
The large number of people entering specialist addiction
services with complex needs and multiple prescriptions
provides an important opportunity for exploring addiction
service prescribers’ views and experiences of assessing the
appropriateness of medications prescribed for service users
coming in for treatment as well as the differences between
the various types of prescribers. Prescribers included in
this study were medical and non-medical. The non-medical
prescribers (NMPs) were independent nurse prescribers
who could assess and also devise a treatment plan that may
include prescribing for service users [
]. NMPs prescribe
within their areas of competence [
]. For instance, nurse
prescribers working in addiction medicine are able to
prescribe substitute opioids, relapse prevention medications,
medications for detoxification and vitamin supplements.
Assessment of the clinical appropriateness of
non-medical prescribing, including nurse prescribing, have concluded
that NMPs generally make clinically appropriate prescribing
]. However, history taking, assessment and
diagnosis skills have been highlighted as areas for further
Service users visiting the service could self-refer or be
referred from a range of sources such as general
practitioners, psychiatrists, hospital, social services, drug services
and the criminal justice system. Consequently, this study
explored specialist addiction service prescribers’ views and
experiences of assessing the appropriateness of medications
prescribed by others.
This study explored specialist addiction service prescribers’
views and experiences of assessing the appropriateness of
medications prescribed for service users coming in for
treatment as well as the differences between prescribers.
Appropriateness was considered to involve maximising
effectiveness, minimising risks and costs, and respecting the patient’s
The study was approved by the University of York’s
Research Governance Committee and the National Research
Ethics Service (NRES) Committee Yorkshire & The
Humber. Reference 12/YH/0325.
Study design and setting
A phenomenological approach was taken to explore
individual views and experiences of assessing the appropriateness
of medications prescribed for service users. Semi-structured
qualitative interviews were carried out with prescribers
comprising nurse prescribers and medical doctors working at the
specialist addiction service. This service is located in a city
in the North of England and is a statutory NHS specialist
service that provides tier 3 level interventions to adults who
misuse alcohol and/or drugs. Tier 3 interventions generally
involve the provision of care-planned interventions
following a comprehensive community-based assessment [
One-on-one interviews were used because it would be very
difficult to get time-pressed clinicians together for a focus
group discussion. In addition, group interviews may be
prohibitive for some prescribers.
Twelve prescribers took part in this study, comprising four
nurse prescribers and eight medical doctors. In line with
qualitative research inquiry, the aim of the sampling
strategy adopted was to recruit respondents who could provide
valuable insight into the topic and also to provide a broad
overview of the perspectives of different prescribers.
Consequently, all the fourteen prescribers working at the specialist
addiction service during the period of this study were
provided with the study details by the chief investigator (A. O).
This was followed by a meeting with each prescriber to
discuss the study in detail after which written informed
consent was sought. Twelve of the fourteen eligible prescribers
were interviewed. Participants included five females, three
of whom were nurse prescribers and two medical doctors
and seven males, of whom one was a nurse prescriber and
six medical doctors. The medical doctors had different levels
of seniority and included one senior house officer (hereafter
SHO), one locum doctor, three specialist registrars (hereafter
SpR) and three consultant addiction psychiatrists. Generally,
the prescribers represented a broad range of qualifications
and experience in the addiction field.1 Nurse prescribers’
ages ranged from 34 to 55 years while doctors were between
31 and 65 years.
Data were collected by the first author, A. O. All the
interviews were conducted at a time convenient for participants
at the specialist addiction service and lasted on average
48 min (range 36–74 min). The topic guide was informed
by knowledge of the literature on prescribing and advice
from the project advisory group (which included one
consultant addiction psychiatrist). The topic guide was piloted
with a consultant addiction psychiatrist and covered the
following areas: definition of inappropriate prescribing, classes
of medications assessed and how assessment is carried out.
The interviews were audio recorded (with permission) and
Data were analysed using thematic framework analysis [
Familiarisation involved repeated reading of transcripts
alongside listening to the audio-recordings and was followed
by a period of descriptive and interpretive coding facilitated
by Atlas ti (v 6.0). This inductive approach enabled a deeper
understanding of the data [
]. As new themes emerged,
they were added to the coding framework. Broader themes
were subsequently generated and frequently reviewed
while comparing data from participants that supported the
themes and also looking for explanations of any differences
of viewpoints within the data. Numbers rather than names
were allocated to participants in order to ensure anonymity
and confidentiality. Trustworthiness of the data was ensured
through an audit trail kept by A.O which detailed how data
1 Nurse prescribers had practiced in addiction specialty for between
1 and 5 years and as nurses for between 5 and 22 years. Two doctors
had no prior experience in addiction specialty while the remaining
had between 6 months and 35 years of experience. Consultant
psychiatrists in particular, had between 3 and 35 years of experience in
addiction specialty. Doctors had between 6 and 41 years of clinical
were collected, how themes were formed and how decisions
were made during the research process. Furthermore, the
interpretation of the data was discussed in-depth with two
of the authors (C.L and E.H), who reflected on the
plausibility of the themes and the depth of the analysis. A. O has a
pharmacy background while C. L and E.H have criminology
and nursing backgrounds respectively. D.R is a consultant
The following themes emerged in response to how
prescribers assessed the appropriateness of prescribed medications:
review of medications, assessing risk, guideline adherence
versus successful prescribing, history-taking and
involvement of service users. There were some areas of differences
in nurse prescribers and medical doctors’ approaches and
also among the different types of medical doctors. These
differences are highlighted in the text.
Review of medications
The classes of medications reviewed varied among
prescribers with three of them (all doctors) with the longest years
of prescribing experience stating that they reviewed all of
service users’ medications for their appropriateness. One of
these three prescribers had 41 years of experience in
prescribing and made the following statement:
So I’d look at the list of drugs prescribed and see how
they matched up to what I thought the person was
showing in terms of addiction illness, physical illness
and mental illness [P3, consultant].
The remaining prescribers consisting of other doctors and
nurse prescribers described a more limited remit. These
doctors considered their scope of practice to encompass
medications for mental health illnesses, addictions and sometimes
opioids for pain relief while nurse prescribers described a
focus on medications used for treating addiction problems.
This quote captures a nurse prescriber’s view:
So I don’t really see, with psychiatric medication, that
that would be within my remit really. If somebody
came and they were prescribed 100 mgs of
methadone and they couldn’t even open their eyes then, I
would be assessing the appropriateness of the dosage
and making necessary adjustments to things like that
Nurse prescribers further described involving doctors at
the specialist addiction service or service users’ general
practitioners (hereafter GPs) if they had particular
concerns about medications. There was an underlying feeling
of cautiousness characterised by their perceptions of their
competency. This was captured by the quote below:
As I say, if I was particularly concerned about
someone’s mood or I have particular concerns about the
medication I would defer to a medic. You know, it’s
not an area I feel strongly confident on [P6, NP].
Doctors at the specialist addiction service were a
valuable source of support to nurse prescribers in
prescribingrelated issues. There was also particular reliance on the
expertise of consultant addiction psychiatrists by both
nurse prescribers and doctors who were not consultants.
A doctor described contacting a GP concerning an
inappropriate medication and the support of her consultant in
providing expert advice when needed:
For the example I started with [patient with
schizophrenia on supra-BNF dose of olanzapine], I wrote
to the GP saying, you know, Mr So-and-So is stable
and is relatively symptom free on this but I’m
worried about this monitoring [olanzapine monitoring]
but generally if I think something’s really
inappropriate and I’m in a position to contact the original
prescriber I’ll try to do that, but I’d always discuss a
case with my consultant and make a decision about
whether or not I need to do something imminently
It appears that prescribers at this specialist addiction
service provided a ‘safety net’ function to other prescribers
such as GPs:
If I find something that’s maybe been overlooked
or prescribed wrongly, then I will let the GP know
about it [P5, Locum].
I’d probably look at it [medication appropriateness]
at the initial assessment and if there’s anything that
comes up or that was sort of glaringly obvious I’d
refer to the GP and ask the GP to review, if they’re
prescribing [P11, NP].
Specialist addiction service prescribers further described
GPs’ varying responses to the need for review of service
Yeah. that has happened on a couple of times where
I’ve written to the GP to ask them to review… there
have been a couple of scenarios where I’ve written
and the GP hasn’t responded or the GP has written
back saying, I don’t feel I’m the best person to do
this, would you refer to a specialist service or would
you basically will you deal with it [P12, SHO].
They also described sometimes taking over prescribing of
psychiatric medications from GPs:
But in general I’d like to take over all of the
psychoactive drugs that somebody gets, at least until the point
that we’re sure that the drugs are appropriate and we’ve
got some sort of stable situation [P3, Consultant].
The evaluation of risk is a theme that was highlighted by
all prescribers as a means through which they assess the
appropriateness of service users’ medications. All the twelve
prescribers said they considered the risk posed by a
medication. Some of the quotations captured this:
Well if it’s going to do, first of all, less harm than the
actual substance, not more harm, so the actual
prescription can be worse than doing nothing [P5, locum
One prescriber described a service user who she felt had an
inappropriate and high risk prescription of olanzapine (an
antipsychotic). The service user was an elderly man who was
being prescribed olanzapine (25 mg) at a dose higher than
that stated in the British National Formulary (BNF) without
monitoring by a psychiatrist:
I have a patient who has a very old diagnosis of
paranoid schizophrenia dating from his late teens, and for
this he’s prescribed a very high dose of medication
called olanzapine and he’s prescribed over the limit
in the BNF and he’s not under the supervision of a
specialist. So I would label that as an inappropriate
prescription because (a) he’s elderly, which means that
he’s more prone to cardiac disease, and the drug can
cause diabetes which can lead to heart disease. It can
cause arrhythmias, he’s not being monitored regularly
with regards to that, and he’s not being monitored with
regards to his clinical symptoms, which, are actually,
from a psychosis point of view, negligible [P12, SHO].
The SHO described contacting the service user’s GP
concerning the antipsychotic medication. His GP refused to
alter it due to the service user’s stability on the dose for a
prolonged period. The GP and SHO differed in their views
concerning the antipsychotic. There was no change made to
Guideline adherence versus successful prescription
The need to assess if prescribing is in line with guidelines
was highlighted. Some prescribers further acknowledged
that the need to individualise prescribing and ensure
optimal functioning may lead to prescribing outside guideline
recommendations. The need to consider the context of
prescribing was emphasised by a nurse prescriber:
And I think any comment about any prescribing should
only be made when you know about the circumstances
in which the decision was made. For example, we
prescribe very high doses of some drugs, now some
people say that you shouldn’t prescribe at those levels, but
they are appropriate if you know about the
circumstances [P1, NP].
A consultant addiction psychiatrist also expressed similar
views and contrasted guideline adherence with successful
Prescribing is something of an art as well as a science,
so prescribers will sometimes prescribe things that
they know are not really indicated but with the aim of
achieving a particular goal [P3, Consultant].
All prescribers identified history-taking as a part of their
assessment of the appropriateness of service users’
medications. The prescribers described enquiring about service
users’ medical and medication history:
Looking at the history of their substance use, history
of any physical health problems, mental health history,
and current mental state as well so I’d get the full
history and I think then you can kind of gauge whether
something might be inappropriately prescribed [P11,
Despite prescribers routinely obtaining a
medical/medication history from service users, most reiterated that it was
not within their remit to explore the appropriateness of all
…I would, in as much as part of the assessment, I
would ask the service user …are they on any
medications. If they are, what it is, what dose, what’s it
prescribed for and are they taking it. That would be
the total sum of my assessment. I wouldn’t move to
beyond exploring that condition or whether that was
appropriate, I don’t think that’s my place [P6, NP].
All prescribers further described some challenges with
selfreport when obtaining service users’ histories. These include
problems with the reliability of information provided by
service users as some of them may withhold information.
This may lead to prescribing of unnecessary medications.
Prescribers also described service users who do not know
details of their medications such as the name and reason
for medication use. Some may be cognitively impaired by
substances and therefore unable to provide necessary
information. Prescribers may have to contact GPs concerning
needed information. There was however an
acknowledgment that contacting GPs for information was not always
routine practice as prescribers tended to rely on information
obtained from service users.
Involvement of service users
This theme was described by all prescribers. It involved
discussing with service users in order to understand their
views concerning the appropriateness of their prescribed
Well, firstly I discuss with the patient to see what the
patient’s view is, and explain what I think, which are
the reasons for this inappropriateness [P13, SpR].
Prescribers also highlighted the fact that lack of
engagement by service users may affect prescribing decisions. For
instance, service users’ medications may need to be stopped
due to repeated non-attendance of clinic appointments.
The evidence from this study shows that the assessment of
the appropriateness of prescribed medications is a complex
judgment. Besides a few more experienced doctors, all other
prescribers (doctors and nurse prescribers) tended to review
only the subset of medications which they saw as within
their competency. It has been recommended that doctors
and nurse prescribers adhere to their areas of competency
for safe practice [
]. Nurse prescribers and doctors
appeared to be working within their competency.
Published evidence suggests non-medical prescribers
generally make clinically appropriate prescribing decisions
with the need for further improvement in assessment,
diagnosis and history-taking skills [
]. Nurse prescribers
described referring service users who they had concerns
about their medications to doctors at the specialist addiction
service or service users’ GPs. Specialist addiction service
doctors particularly represented a valuable source of
support to nurse prescribers when dealing with issues around
prescribing. The more junior doctors (non-consultants) also
relied on their senior colleagues, especially consultant
addiction psychiatrists, for expert advice on medications. There
was further evidence that prescribers were a sort of ‘safety
net’ against medication-related risks as they intervened and
contacted GPs if they found serious problems with service
Service users pose particular challenges in terms of
complexity and risk issues. They often have complex needs
including severe comorbid mental and physical health
]. In order to meet these needs, Public Health
England  has recommended that addiction specialist
doctors such as consultant psychiatrists work alongside
nonmedical prescribers and other doctors in a multidisciplinary
team. The drug and alcohol treatment system has however
undergone some changes in commissioning in recent years.
This has involved a move from mainly NHS service
provision to a more mixed economy of service providers [
These changes have led to a decrease in the number of
doctors including consultant addiction psychiatrists in treatment
], with nurses taking on more prescribing roles.
Consequently, there is a reduction in the capacity of these
new treatment systems for specialist expertise and complex
It appears that there is a possibility of reduction in the
quality of prescribing and decision-making as a result of
these changes as nurse prescribers and GPs may not have
ready access to support and specialist knowledge when
required. The potential for specialists to provide clinical
supervision that will support nurse prescribers in making
clinically appropriate decisions when needed is also
hampered. It appears future prescribing practice in alcohol and
drug treatment systems will mostly involve nurse
prescribers. This raises concerns about the future review practices
of psychiatric medications in addiction services if nurse
prescribers are not further strengthened to work with
service users, including complex clients. In addiction service
users, psychiatric comorbidity is highly prevalent [
and medications used in their management have often been
implicated in overdose and fatalities [
support could be enlisted to guide prescribing decisions for
service users with complex comorbidity. This approach may
assist in improving medicines management among service
There is the need to equip nurse prescribers to work with
service users, especially complex cases. Given that
assessment, diagnosis and history-taking skills are pre-requisites
for undertaking the nurse prescribing qualification, these
skills may well be further developed through training to
enable nurse prescribers manage complex service users,
especially those with comorbid mental disorders. Practice
should include regular supervision of nurse prescribers by
an experienced doctor or nurse prescriber to ensure that they
are making optimal clinical decisions.
The relationship between healthcare professionals and
service users have changed over the years from a
predominantly paternalistic model to one in which service users have
increasingly become active partners whose views are
]. Involving service users assists the prescriber in
eliciting their views and is useful in decision-making
concerning treatment . There is evidence that building a
positive relationship can lead to positive client and treatment
]. Despite these potential benefits, prescribers
identified problems that may occur when trying to involve
service users in decision-making. The quality of
information provided by service users may be poor as a result of
cognitive impairment or even deliberate withholding of
information. When service users are actively misusing
substances, prescribers lose access to the most fundamental tool
in medicine, the patient’s self-report [
]. While some
prescribers described contacting service users’ GPs for further
information concerning medications, this was not done by
Depending on information obtained from only service
users in assessing appropriateness implies that medications
which are potentially inappropriate may not be identified
if service users fail to mention them. There is the
possibility that different prescribers may go ahead to prescribe
undisclosed medications such as multiple central nervous
system depressants. In addiction medicine, there should be
careful consideration of self-report and collateral
information should be sought where possible [
]. Shared medical
] and good communication among different
service providers are essential in obtaining accurate medical/
medication histories and reducing the potential for multiple
prescribing, drug interactions, overdose incidents and
conflicting treatment plans [
The limited applicability of guidelines to service users
was also recognised by prescribers. Guidelines often have a
disease-specific focus and limited applicability to the
varying needs of individual patients [
]. Although prescribing
outside guideline recommendations carries its own risks
including the potential for greater severity of unwanted
side effects [
], there needs to be a weighing of such risks
against more pragmatic outcomes that may be of great
importance to service users.
Strengths and limitations
To the knowledge of the authors, this is the first study to
explore the views and experiences of specialist addiction
service prescribers when assessing the appropriateness of
prescribed medications among service users coming to this
setting. Owing to the fact that the interviews were conducted
with prescribers after they had taken part in an earlier study
in which the appropriateness of opioids and psychiatric
medications were assessed using a modified form of the
Medication Appropriateness Index [
], it is possible that
participation in this initial study may have influenced some of their
responses to the different areas explored in the interviews.
Consequently, prescribers’ responses might be different if
they were interviewed before taking part in this initial study.
The findings may lack generalisability to prescribers in
other addiction services, especially given the changes that
have occurred in drug and alcohol treatment services in the
UK. There has been an increase in the number of third sector
organisations (non-statutory service providers and the
private sector) providing drug and alcohol services. Availability
of medical expertise has also diminished in these services.
Further research should involve multiple sites (including
services run by the NHS and third sector organisations), to
establish if the findings of this study are applicable. Given
the reducing levels of medical expertise among staff in
specialist addiction services, an important area to explore will
be the role and scope of nurse prescribers: including their
views on the changing drug treatment landscape,
management of service users (especially those with complex needs),
the support available to nurse prescribers and their training
needs. Similarly, there may well be need to interview GPs
on these areas since it was evident that specialist addiction
service prescribers provided some level of support to them.
Furthermore, data collection was by a single researcher.
There is the possibility that the researcher’s own
perspectives may have affected interpretations that were made.
However, the conduct, analysis and interpretation of data were
overseen by two of the authors in addition to A.O.
Assessment of the appropriateness of prescribed
medications appeared to be a complex judgment. Optimal
assessment of prescribing appropriateness should involve a balance
between guideline recommendations, risks and benefits of
prescribing, and the context. Nurse prescribers and medical
doctors differed in their approach to reviewing medications
but appeared to be working within their competency, with
doctors providing support to nurse prescribers when needed.
Prescribers were a sort of ‘safety net’ against
medicationrelated risks to GPs. Recent changes in the UK drug and
alcohol field have led to diminishing availability of medical
expertise and an increasing reliance on non-medical
prescribing. These changes have the potential to affect the
quality of decision-making around medications. It appears there
is a need to further empower non-medical prescribers and
GPs to effectively manage service users with comorbidity.
Acknowledgements The authors are grateful to all those that
participated in this study, and also for the helpful comments on an earlier
draft of this paper by two reviewers.
Funding This study is part of independent research funded by the
National Institute of Health Research (NIHR) through the NIHR
Collaboration for Leadership in Applied Health Research and Care for
Leeds, York and Bradford.
Conflicts of interest The authors declare that there are no conflicts
Open Access This article is distributed under the terms of the
Creative Commons Attribution 4.0 International License
(http://creativecommons.org/licenses/by/4.0/), which permits unrestricted use,
distribution, and reproduction in any medium, provided you give
appropriate credit to the original author(s) and the source, provide a link to
the Creative Commons license, and indicate if changes were made.
1. McLellan T. Revisiting the past for a look toward future research: a final editorial . J Subst Abuse Treat . 2009 ; 36 ( 4 ): 352 - 4 .
2. Mortlock KS , Deane FP , Crowe TP . Screening for mental disorder comorbidity in Australian alcohol and other drug residential treatment settings . J Subst Abuse Treat . 2011 ; 40 ( 4 ): 397 - 404 .
3. Oluyase AO , Raistrick D , Abbasi Y , Dale V , Lloyd C. A study of the psychotropic prescriptions of people attending an addiction service in England . Adv Dual Diagn . 2013 ; 6 ( 2 ): 54 - 65 .
4. Cunningham JA , Breslin FC . Only one in three people with alcohol abuse or dependence ever seek treatment . Addict Behav . 2004 ; 29 ( 1 ): 221 - 3 .
5. Tucker JA , Simpson CA . The recovery spectrum: from self-change to seeking treatment . Alcohol Res Health . 2011 ; 33 ( 4 ): 371 - 9 .
6. Hughes E. Guidelines for working with mental health-substance use . In: Cooper DB, editor. Developing services in mental healthsubstance use . London: Radcliffe Publishing Ltd; 2011 .
7. Inciardi JA , Surratt HL , Kurtz SP , Cicero TJ . Mechanisms of prescription drug diversion among drug-involved club- and streetbased populations . Pain Med . 2007 ; 8 ( 2 ): 171 - 83 .
8. Savage SR , Kirsh KL , Passik SD . Challenges in using opioids to treat pain in persons with substance use disorders . Addict Sci Clin Pract . 2008 ; 4 ( 2 ): 4 - 25 .
9. Boscarino JA , Kirchner HL , Pitcavage JM , Nadipelli VR , Ronquest NA , Fitzpatrick MH , et al. Factors associated with opioid overdose: a 10-year retrospective study of patients in a large integrated health care system . Subst Abuse Rehabil . 2016 ; 77 : 131 - 41 .
10. Darke S , Duflou J , Torok M. Toxicology and characteristics of fatal oxycodone toxicity cases in New South Wales , Australia 1999 -2008. J Forensic Sci. 2011 ; 56 ( 3 ): 690 - 3 .
11. Zamparutti G , Schifano F , Corkery JM , Oyefeso A , Ghodse AH . Deaths of opiate/opioid misusers involving dihydrocodeine , UK, 1997 - 2007 . Br J Clin Pharmacol . 2011 ; 72 ( 2 ): 330 - 7 .
12. Darke S , Hall W. Heroin overdose: research and evidence-based intervention . J Urban Health . 2003 ; 80 ( 2 ): 189 - 200 .
13. Darke S , Ross J. The use of antidepressants among injecting drug users in Sydney, Australia . Addiction. 2000 ; 95 ( 3 ): 407 - 17 .
14. Department of Health. Review of prescribing, supply and administration of medicines: final report (Crown II) . London: Department of Health; 1999 .
15. Cope LC , Abuzour AS , Tully MP . Non-medical prescribing: where are we now? Ther Adv Drug Saf . 2016 ; 7 ( 4 ): 165 - 72 .
16. Latter S , Smith A , Blenkinsopp A , Nicholls P , Little P , Chapman S. Are nurse and pharmacist independent prescribers making clinically appropriate prescribing decisions? An analysis of consultations . J Health Serv Res Policy . 2012 ; 17 ( 3 ): 149 - 56 .
17. Naughton C , Drennan J , Hyde A , Allen D , O'Boyle K , Felle P , et al. An evaluation of the appropriateness and safety of nurse and midwife prescribing in Ireland . J Adv Nurs . 2013 ; 69 ( 7 ): 1478 - 88 .
18. Lexchin J. Improving the appropriateness of physician prescribing . Int J Health Serv . 1998 ; 28 ( 2 ): 253 - 67 .
19. National Treatment Agency for Substance Misuse . Models of care for alcohol misusers (MoCAM) . London: National Treatment Agency for Substance Misuse ; 2006 .
20. Miles MB , Huberman AM . Qualitative data analysis: a sourcebook of new methods . Beverly Hills: Sage Publications; 1994 .
21. Silverman D. Doing qualitative research: a practical handbook . London: Sage Publications; 2013 .
22. Public Health England. Non-medical prescribing in the management of substance misuse . London: Public Health England; 2014 . http://www.nta.nhs.uk/uploads/nmp -in-the-management-of-substance-misuse . pdf. Accessed 23 Jul 2015 .
23. Public Health England. The role of addiction specialist doctors in recovery orientated treatment systems. A resource for commissioners, providers and clinicians . London: Public Health England; 2014 . http://www.nta.nhs.uk/uploads/the -role-of-addiction-specialist-doctors . pdf. Accessed 23 Jul 2015 .
24. Virgo N , Bennett G , Higgins D , Bennett I , Thomas P. The prevalence and characteristics of co-occurring serious mental illness (SMI) and substance abuse or dependence in the patients of adult mental health and addictions services in eastern Dorset . J Ment Health . 2001 ; 10 ( 2 ): 175 - 88 .
25. Strathdee G , Manning V , Best D , Keaney F , Bhui K , Witton J , et al. Dual diagnosis in a primary care group (PCG), (100,000) population locality: a step-by-step epidemiological needs assessment and design of a training and service response model . Drugs Educ Prev Policy . 2005 ; 12 ( 1 ): 119 - 23 .
26. Weaver T , Madden P , Charles V , Stimson G , Renton A , Tyrer P , et al. Comorbidity of substance misuse and mental illness in community mental health and substance misuse services . Br J Psychiatry . 2003 ; 183 ( 4 ): 304 - 13 .
27. Delgadillo J , Godfrey C , Gilbody S , Scott P. Depression, anxiety and comorbid substance use: association patterns in outpatient addictions treatment . Ment Health Subst Use . 2013 ; 6 ( 1 ): 59 - 75 .
28. Walsh K , Copello A . Severe and enduring mental health problems within an established substance misuse treatment partnership . Psychiatr Bull . 2014 ; 38 ( 5 ): 216 - 9 .
29. Dickey B , Normand SL , Weiss RD , Drake RE , Azeni H . Medical morbidity, mental illness, and substance use disorders . Psychiatr Serv . 2002 ; 53 ( 7 ): 861 - 7 .
30. Elwyn G , Edwards A , Kinnersley P . Shared decision-making in primary care: the neglected second half of the consultation . Br J Gen Pract . 1999 ; 49 ( 443 ): 477 - 82 .
31. Bezreh T , Laws MB , Taubin T , Rifkin DE , Wilson IB. Challenges to physician-patient communication about medication use: a window into the skeptical patient's world . Patient Prefer Adherence . 2012 ; 6 : 11 - 8 .
32. Barnett PB . Rapport and the hospitalist . Am J Med . 2001 ; 111 ( 9B ): 31S - 5S .
33. Leach MJ . Rapport: a key to treatment success . Complement Ther Clin Pract . 2005 ; 11 ( 4 ): 262 - 5 .
34. Action on Addiction. The management of pain in people with a past or current history of addiction . London: Action on Addiction; 2013 . http://www.actiononaddiction.org.uk/Documents/ TheManagement-of-Pain-in-People-with-a-Past-or-Cu.aspx . Accessed 23 Jul 2015 .
35. Ghitza UE , Sparenborg S , Tai B . Improving drug abuse treatment delivery through adoption of harmonised electronic health record systems . Subst Abuse Rehabil . 2011 ; 2 : 125 - 31 .
36. Farquhar CM , Kofa EW , Slutsky JR . Clinicians' attitudes to clinical practice guidelines: a systematic review . Med J Aust. 2002 ; 177 ( 9 ): 502 - 6 .
37. Ali SI , Ajmal SR . When is off-label prescribing appropriate? Curr Psychiatr . 2012 ; 11 ( 7 ): 23 - 7 .
38. Hanlon JT , Schmader KE , Samsa GP , Weinberger M , Uttech KM , Lewis IK , et al. A method for assessing drug therapy appropriateness . J Clin Epidemiol . 1992 ; 45 ( 10 ): 1045 - 51 .