Opioid Use Disorder: Screening, Diagnosis, and
Privia Randhawa
, Seonaid Nolan
British Columbia Centre on Substance Use, Vancouver, BC, Canada;
Department of Medicine, University of British Columbia, St.
Pauls Hospital, Vancouver, BC, Canada
Author for correspondence: Seonaid Nolan:
13 February 2020; Accepted after revision: 27 April 2020; Published: 21 June 2021
Over the past decade, the opioid crisis in Canada has been worsening. In 2019, over 3,800
across Canada died due to an apparent opioid-related cause, which represents a 26%
increase from just 3 years prior. Given North Americas ongoing opioid crisis, and the
contribution opioid-prescribing practices have had to date, a critical need exists to ensure that
health care providers are not only educated about safe opioid prescribing but also are
knowledgeable about how to effectively screen for, diagnose, and treat an individual with
opioid use disorder.
Au cours des dix dernières années, la crise des opioïdes au Canada na cessé de saggraver. En
2019, plus de 3 800personnes au Canada sont décédées dune cause apparemment liée à la
consommation dopioïdes, ce qui représente une augmentation de 26% par rapport à
trois ans auparavant. Étant donné la crise des opioïdes qui sévit actuellement en
Amérique du Nord et la contribution des pratiques de prescription d’opioïdes qui ont eu cours
jusqu’ici, un
besoin critique est à combler pour veiller à ce que les fournisseurs de soins soient
non seulement
formés sur la prescription sécuritaire des opioïdes, mais aussi bien informés
sur le dépistage, le diagnostic et le traitement efficace d’un trouble lié à la consommation
Canada is in the midst of an opioid crisis that has been progressively
worsening. In 2019, over 3,800 Canadians died of an opioid-
related cause, which represents a 26% increase from just 3
prior in 2016.
Though British Columbia (BC) has been
facing a
disproportionate number of deaths per year, the
opioid crisis is
affecting communities from every province
and territory across
Canada, with similar trends being seen in
the United States.
While reasons for North Americas recent increase in opioid-
related deaths are certainly multifactorial, opioid-prescribing
practices related to the treatment of acute and/or chronic pain
has previously been recognized as a significant contributor.
Though Canadian data is lacking, prescription opioid misuse
was found to be the second most common illicit drug used (after
marijuana) in the previous month by surveyed Americans (aged
12 years or older) in 2018.
Similarly, almost 20% of the 53 million
Americans who reported past-year use of illicit drugs in 2018
reported the misuse of prescription opioids.
While a significant
proportion of individuals who misused prescription opioids
did so to relieve physical pain (64%), the second most common
reason cited was to feel good or get high (11%). Regarding the
source of misused prescription opioids, approximately 51% were
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given by, bought from, or taken from a friend or relative, while
37% obtained opioids directly through a prescription.
Canada is now the second highest global opioid consumer,
after the United States, with rates of pharmaceutical opioid
use having tripled over the past decade alone.
For many
years, prescribers have been faulted for oligoanesthesia—the
undertreatment of acute pain.
To ensure pain was not dismissed
and instead treated sufficiently, there was a push for physicians
to treat pain more aggressively.
In addition, pharmaceutical
companies employed forceful, and sometimes deceiving,
marketing strategies to increase opioid sales.
these influences have contributed to steep increases in opioid
prescriptions over the past decade, in every province across
As recent evidence and guidelines are beginning to
highlight, opioids have limited effectiveness in the treatment
of chronic, noncancer pain.
Moreover, the risks of opioid use
likely outweigh their potential short-term benefits when used
to treat mild to moderate acute pain.
Beyond increased rates of opioid prescribing, there is also
evidence of high-risk prescribing practices. BC data, for example,
demonstrate that among patients being prescribed methadone
maintenance treatment for an opioid use disorder, approximately
35% also received a concurrent prescription for an additional
opioid between 1996 and 2006.
Furthermore, the number of
opioid prescriptions per person per year nearly doubled within
the same timeframe.
Looking at the source of concurrent
opioid prescriptions, the vast majority (74%) were prescribed to
a patient by a physician that was not their methadone provider.
Such a practice proves problematic as the co-prescription of
opioids and methadone have important safety considerations
as evidenced by the risk of fatal and nonfatal overdoses related
to concurrent opioid use.
While opioid-prescribing practices have undoubtedly contributed
to North Americas opioid crisis, the presence of fentanyl (and its
potent analogues) in the illicit drug supply cannot be ignored.
In 2019, 77% of accidental, apparent opioid-related deaths in
Canada involved fentanyl or one of its analogues compared to
only 54% of apparent opioid-related deaths in 2016.
The use
of nonmedical prescription opioids, however, has previously
been identified to be a risk factor for subsequent illicit opioid
use (with some studies citing up to a 40-fold increased risk for
the development of a heroin use disorder among those with
a nonmedical prescription opioid use disorder compared to
those without).
More specifically, a 2013 national US study
demonstrated that among individuals with both nonmedical
prescription opioid use and heroin use in the preceding year,
77% reported their heroin use was concerned with nonmedical
prescription opioids.
Accordingly, given North Americas
ongoing opioid crisis and the contribution opioid-prescribing
practices have had to date, a critical need exists to ensure health
care providers are not only educated about safe opioid prescribing
but also are knowledgeable about how to effectively screen for,
diagnose, and treat an individual with opioid use disorder.
Opioid Use Disorder: Screening and Diagnosis
Historically, there has been a lack of focus on pain management
or addiction medicine training in medical education (both in
Canada and the United States). Accordingly, screening patients for
either substance misuse or addiction is not routinely integrated
into many clinicians existing workflows. Though Canadian data
are lacking, one national survey of primary care physicians in
the United States demonstrated 94% of respondents (n = 648)
reported being unable to identify a substance use disorder among
their adult patients.
Accordingly, being able to accurately screen
for and diagnose opioid use disorder is of critical importance.
The Rapid Opioid Dependence Screen (RODS) is an eight-
item survey that can provide targeted screening for opioid
dependence (as defined by the Diagnostic and Statistical Manual
of Mental Disorders [DSM], Fourth Edition) in either a clinical
or research setting.
The instrument, on average, takes less than
2 minutes to administer and can be done individually or as
of a more thorough assessment. The RODS has
demonstrated good-to-strong sensitivity (97%) and specificity
(76%), among newly incarcerated HIV-infected individuals.
An individual
screens “positiveif they respond “yes” to at least
three questions.
A “positivescreen should then be followed
up with a formal
diagnosis of opioid use disorder using the
11-item criteria from
the DSM-Fifth Edition. The severity of
opioid use disorder can
further be classified as mild (score:
2–3), moderate (score: 4–5), or
severe (score≥ 6). Additional
screening tools have been validated
in various populations,
for example, the Mini International
Interview (MINI) and the National Institute
on Drug Abuse
Modified Alcohol, Smoking, and Substance
Screening Test (NMASSIST).
As each screening/
tool has specific benefits and drawbacks in relation to
reliability, validity, and time of administration, it is important
carefully consider the most appropriate choice dependent on
population at hand. Most importantly, any individual
with an opioid use disorder should be offered and
on evidence-based treatment in a timely fashion by
either the
patients primary care provider or referral to a
practitioner with
expertise in addiction medicine.
Opioid Use Disorder: Management
In the spring of 2018, a national Canadian guideline for the
treatment of opioid use disorder was published.
The guideline
describes the need for the treatment of opioid use disorder to
occur along a continuum, with treatment intensity matched
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to disease severity. Furthermore, a need exists for ongoing
reassessment to ensure a patients treatment needs (which may
evolve over time) are consistently being met. Harm reduction
strategies (e.g., take-home naloxone kits, safe injection, or overdose
prevention education) and/or psychosocial interventions (e.g.,
counselling, group therapy, residential treatment) should span
the entire treatment continuum and be offered to all patients
as standard practice.
Withdrawal management
Withdrawal management (e.g., detox) is considered merely
symptom management in the realm of treatment modalities
for opioid use disorder and, therefore, should not be used as
a treatment option without additional support. Methadone
and buprenorphine/naloxone can be used as a taper to reduce
symptoms of opioid withdrawal, albeit with certain risks.
example, many patients did not complete treatment and there
were high rates of relapse during and after tapers, which results
in the potential of overdoses and deaths.
In addition, although alpha
-adrenergic agonists (e.g.,
clonidine) tend to relieve opioid withdrawal symptoms faster
than a methadone taper and usually require a shorter length of
treatment, they may also be associated with certain side effects
including sedation, dry mouth, and/or hypotension.
buprenorphine/naloxone provides more rapid symptom relief
for opioid withdrawal and its use is associated with higher rates
of withdrawal management completion when compared to a
methadone taper.
Furthermore, compared to alpha
agonists, buprenorphine/naloxone is more effective at relieving
opioid withdrawal symtpoms.
Regardless of which medication
is used, it is important to note that withdrawal management
should never be offered in isolation (e.g., without transition to
ongoing maintenance therapy) as such an approach is associated
with higher rates of relapse,
HIV infection and transmission,
and increased morbidity and mortality.
In addition, pairing
psychosocial interventions with medical management appears
to be a helpful adjunct in the context of opioid withdrawal
Opioid agonist therapy
First-line treatment for opioid use disorder is opioid agonist
therapy. Given its improved safety profile (and decreased risk for
diversion), buprenorphine/naloxone is currently recommended
as first-line therapy for opioid use disorder treatment.
Buprenorphine is a partial opioid agonist, and confers a lower
risk for sedation and respiratory depression, as well as a sixfold
decreased risk for overdose when compared to methadone.
Furthermore, the medication has few drug-drug interactions and
is not associated with prolongation of the cardiac QT interval.
Compared to placebo, buprenorphine/naloxone is associated
with increased rates of treatment retention (buprenorphine
daily dose >2 milligrams [mg]) and suppression in illicit opioid
use (buprenorphine daily dose ≥16 mg).
Therapeutic dosing
of buprenorphine/naloxone can be achieved within 24–72 h,
and given its safety profile, the medication can be prescribed
for take-home dosing earlier than methadone. Moderate to
severe withdrawal from full opioid agonists (either prescribed or
illicit) must be achieved for a period of time prior to induction
to prevent the occurrence of precipitated withdrawal. While
more novel induction techniques (e.g., the Bernese method of
buprenorphine/naloxone microdosing) can be successful without
the need for the patient to experience opioid withdrawal, such an
approach is currently off-label.
Specific details regarding how
to prescribe buprenorphine/naloxone for opioid use disorder
treatment can be found in province-specific guidelines.
Methadone, a full opioid agonist, has been available as a
treatment option for opioid use disorder since 1965. Accordingly,
its efficacy is supported by a large body of literature, spanning
various countries, jurisdictions, and socioeconomic settings.
Compared to placebo, methadone maintenance therapy has been
shown to be significantly more effective in addiction treatment
retention, suppression of illicit opioid use,
reduction in mortality
(2.6 versus 12.7 per 1000 person years),
and reduction in HIV
When buprenorphine/naloxone and methadone
are compared, both medications (when prescribed at medium
or high doses [≥ 7mg daily buprenorphine/naloxone, 40mg
daily methadone]) have proven equally efficacious for retention
in addiction treatment and reduction in illicit opioid use.
Given the prolonged half-life of methadone, dose adjustments
are currently recommended every 3 to 7 days (depending on
specific provincial guidelines and risk of patient methadone
Accordingly, it can take weeks or even months
to achieve a therapeutic dose. During this period, it is not
uncommon for patients to discontinue treatment, experience
adverse events, or overdose.
Specific details regarding how to
prescribe methadone for opioid use disorder treatment can be
found in province-specific guidelines.
Novel and emerging treatments
Slow-release oral morphine (SROM) is a 24-h, extended release
formulation of morphine that can be prescribed as an alternative
treatment option to either methadone and/or buprenorphine/
naloxone for opioid use disorder. Although a 2013 Cochrane
review did not show conclusive results in treatment retention
or effectiveness of SROM, it is important to note that only
three studies were available at the time and thus included in the
Since then, data have emerged demonstrating the
efficacy of SROM (when compared to methadone) with regard
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to similar rates of addiction treatment retention,
a reduction in
illicit opioid use and cravings,
as well as no interaction with the
cardiac QTc interval.
If buprenorphine/naloxone or methadone
is unsuccessful or contraindicated for the treatment of opioid
use disorder, SROM should be considered. Of note, a portion
of the studies investigating SROM have been uncontrolled,
pointing to a need for more robust trials. Therefore, SROM is
not recommended as a first-line treatment option for opioid use
disorder. Health care providers should seek expert consultation
from an addiction medicine specialist prior to prescribing.
Injectable opioid agonist therapy (iOAT), such as
diacetylmorphine (DAM), the active ingredient in heroin, has
been offered as a treatment for severe opioid use disorder in
several European settings for decades.
Individuals who have
experienced treatment failure with oral opioid agonist therapy
(e.g., buprenorphine/naloxone, methadone, SROM) may be
considered for treatment with iOAT, which has demonstrated
efficacy in improving addiction treatment retention, reducing
illicit opioid and stimulant use, ensuring decreased criminal
activity, and improving social functioning.
In Canada, injectable
DAM is currently only available through the federal Special
Access Program, which greatly limits its availability as a treatment
In 2015, injectable hydromorphone was found to be
noninferior to injectable DAM in a Vancouver-based randomized
controlled trial.
Subsequent to this, injectable hydromorphone
was approved as a treatment option for severe opioid use disorder
among Canadian adults in the spring of 2019. A few months
later, Canada adopted national iOAT guidelines for the treatment
of opioid use disorder.
Of note, however, prescribing of iOAT
for the treatment of opioid use disorder is limited to health care
providers with appropriate training and expertise.
Antagonist therapies
Naltrexone is an opioid antagonist that binds to opioid
receptors and blocks the effects of other opioid agonists. Oral
naltrexone has been evaluated as a treatment option for opioid
use disorder, but compared to placebo or no treatment, the
medication demonstrated no significant difference in treatment
retention or abstinence rates in a 2011 meta-analysis.
to its oral counterpart, extended-release naltrexone has been
shown to increase adherence to therapy, partially attributed to its
intramuscular route of administration.
In addition to decreased
opioid cravings when compared to methadone, patients who use
extended-release naltrexone for OUD have improved treatment
retention and reduced illicit opioid use overall, when compared
to placebo.
In contrast to the United States, extended-release
naltrexone is not available to Canadians unless it is approved
through Health Canada on a case-by-case basis. In addition to
the hurdle of availability, patients are required to pay for it, as
it does not fall under provincial medical coverage.
Over the past decade, the opioid-related death toll has
continued to increase, prompting a public health emergency
in both Canada and the United States. Though reasons for the
current opioid crisis are multifactorial, health care providers
opioid-prescribing practices and the prevalence of fentanyl
and other potent analogues in the illicit drug supply have been
highlighted as significant contributors. Moving forward, if we
are ever to turn the tide on the opioid epidemic a critical need
exists to ensure health care providers are not only educated
about safe opioid prescribing but also are knowledgeable about
how to effectively screen for, diagnose, and treat an individual
with opioid use disorder. Furthermore, opioid agonist treatment
(e.g., buprenorphine/naloxone, methadone) should be routinely
offered to any patient identified to have an opioid use disorder to
prevent the negative consequences associated with ongoing use.
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