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The Journal of Rheumatology
with Rheumatic Diseases
Position Statement: A Pragmatic Approach for Medical Cannabis and Patients
Canadian Rheumatology Association
Mary-Ann Fitzcharles, Omid Zahedi Niaki, Winfried Hauser, Glen Hazlewood and the
http://www.jrheum.org/content/early/2019/01/11/jrheum.181120
DOI: 10.3899/jrheum.181120
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in rheumatology and related fields.
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1
Fitzcharles, et al: Medicinal cannabis in rheumatic disease
Pers onal non -com merc ial use only. The Journal of Rheumatology Copyright © 2019. All rights reserved.
Position Statement: A Pragmatic Approach for Medical
Cannabis and Patients with Rheumatic Diseases
Mary-Ann Fitzcharles, Omid Zahedi Niaki, Winfried Hauser, and Glen Hazlewood,
and the Canadian Rheumatology Association
ABSTRACT. Objective.Pain is one reason some rheumatology patients may consider use of medical cannabis, a
product increasingly perceived as a safe and neglected natural treatment option for many conditions.
Legalization of recreational cannabis in Canada will promote access to cannabis. Physicians must
therefore provide patients with the best evidence-based information regarding the medicinal effects
and harm of cannabis.
Methods.The Canadian Rheumatology Association (CRA) mandated the development of a position
statement for medical cannabis and the rheumatology patient. The current literature regarding the
effects of medical cannabis for rheumatology patients was assessed, and a pragmatic position
statement to facilitate patient care was developed by the Therapeutics Committee of the CRA and
approved by the CRA board.
Results.There are no clinical trials of medical cannabis in rheumatology patients. Evidence is insuf-
ficient about the benefit of pharmaceutical cannabinoids in fibromyalgia, osteoarthritis, rheumatoid
arthritis, and back pain, but there is evidence of a high risk of harm. Extrapolating from other condi-
tions, medical cannabis may provide some symptom relief for some patients. Short-term risks of
psychomotor effects can be anticipated, but longterm risks have not been determined and are of
concern.
Conclusion.Despite lack of evidence for use of medical cannabis in rheumatology patients, we
acknowledge the need to provide empathetic and pragmatic guidance for patient care. This position
statement aims to facilitate the dialogue between patients and healthcare professionals in a mutually
respectful manner to ensure harm reduction for patients and society. (J Rheumatol First Release
January 15 2019; doi:10.3899/jrheum.181120)
Key Indexing Terms:
RHEUMATIC DISEASE MEDICAL CANNABIS
From the Alan Edwards Pain Management Unit, and the Division of
Rheumatology, McGill University Health Centre, Montreal, Quebec;
Division of Rheumatology, University of Alberta, Calgary, Alberta,
Canada; Department Internal Medicine I, Klinikum Saarbrücken,
Saarbrücken; Department of Psychosomatic Medicine and Psychotherapy,
Technische Universität München, Munich, Germany.
M.A. Fitzcharles, MB ChB, Alan Edwards Pain Management Unit, and
Division of Rheumatology, McGill University Health Centre; O. Zahedi
Niaki, MD, Division of Rheumatology, McGill University Health Centre;
W. Hauser, Dr. med., Department Internal Medicine I, Klinikum
Saarbrücken, and Department of Psychosomatic Medicine and
Psychotherapy, Technische Universität München; G. Hazlewood, MD,
Division of Rheumatology, University of Alberta.
Address correspondence to Dr. M.A. Fitzcharles, Montreal General
Hospital, McGill University Health Centre, 1650 Cedar Ave., Montreal,
Quebec H3G 1A4, Canada. E-mail: mary-ann.fitzcharles@muhc.mcgill.ca
Accepted for publication November 27, 2018.
Persistent pain may cause some rheumatology patients to
explore treatment options outside mainstream medicine.
Cannabinoids may hold promise for attenuation of pain and
inflammation by modulating the endogenous endocan -
nabinoid system1. The popularized purported benefits of
herbal cannabis for many symptoms have catapulted cannabis
into the therapeutic arena. Specifically pertinent to rheumatic
diseases is the preclinical evidence for effect of cannabinoids
on immunological mechanisms with potential to modulate
inflammation and perhaps function as a disease modifier, but
with caution to emphasize that these concepts have not been
observed in patient populations2.
Herbal cannabis, the best-known natural source of
cannabinoids, is a genus of flowering plant in the family of
Cannabaceae, with the species Cannabis sativa most
commonly used therapeutically. The leaves and flowers
contain many molecules, of which Δ9-tetrahydrocannabinol
(THC) and cannabidiol (CBD) are the most studied. In
addition to THC and CBD, herbal cannabis contains many
noncannabinoid molecules, with physiologic effects that are
largely unknown. Medical cannabis refers to the whole plant
or extract thereof, used for medical purposes as dried flowers
and leaves or an oil extract, and may be administered by
smoking, inhalation through a vaporizer (heating to lower
temperatures than smoking), ingestion, or topical applica-
tions. Cannabinoids are also available as pharmaceutical-
quality preparations, either as plant extracts with specified
doses of THC and CBD, or synthesized products acting on
cannabinoid receptors.
Medical cannabis has been legally available to Canadians
Journal of Rheumatology The on January 19, 2019 - Published by www.jrheum.orgDownloaded from
since 2001. There are currently about 250,000 users regis-
tered with Health Canada, many of whom have muscu-
loskeletal complaints3. In contrast to this prevalent use,
rheumatologists are insecure about many aspects of this
treatment strategy. In a recent survey, over 80% of Canadian
rheumatologist respondents reported being asked at least
weekly about medical cannabis, but three-fourths reported
limited confidence in their knowledge of cannabinoids, or
their ability to effectively advise patients4. The need for
practical, patient-centered, evidence-based guidance will
increase with the legalization of recreational cannabis. In an
effort to reconcile these diverse and conflicting opinions,
unbiased and empathetic guidance is urgently required.
MATERIALS AND METHODS
This position statement was developed to provide information and practical
guidance for Canadian rheumatologists regarding medical cannabis in
rheumatology practice, and does not cover pharmaceutical cannabinoid
preparations. The target audience is rheumatologists, who will be required
to respond to patient requests for advice regarding medical cannabis and to
care for patients who may be self-medicating, or who may choose to
formally prescribe medical cannabis.
This document was developed by the Therapeutics Committee and the
Canadian Rheumatology Association (CRA). According to CRA policies,
position statements are designed as an immediate response to an emerging
or controversial topic, adhering to the standards of evidence-based literature
to support statements5.
The relevant literature was reviewed with special attention to the position
paper by the European Pain Federation, as well as a recent clinical practice
guideline published for Canadian family physicians6,7. This latter guideline
assessed use of all cannabinoids for various complaints and appended
summaries of provincial regulatory requirements. Using the GRADE
(Grading of Recommendations Assessment, Development, and Evaluation)
methodology, the results of 4 systematic reviews were used to support state-
ments8. This guideline was rated as high quality according to the Appraisal
of Guidelines Research and Evaluation (AGREE)-II instrument by 2
independent reviewers (GH, MAF). Relevant statements and supporting
evidence pertinent to rheumatic diseases from all publications were
reviewed, and a draft document was developed by the present authors; this
document was circulated to members of the Therapeutics Committee of the
CRA as well as an external expert, and was revised in an iterative fashion
based on feedback. The final document was reviewed and approved by the
CRA board, in accordance with CRA policy.
RESULTS
The recent Canadian guideline for prescribing medical
cannabinoids in primary care addressed the use of cannabi-
noids for pain associated with rheumatologic conditions6.
There were no randomized trials of medical cannabis in
rheumatic diseases6,9. Additionally, there was insufficient
evidence for the benefit of pharmaceutical preparations for
fibromyalgia, osteoarthritis, rheumatoid arthritis, and back
pain, but there was evidence of a high risk of harm10,11. In
evaluating the harm of medical cannabis reported for pain in
conditions other than rheumatic complaints, there was a high
rate of short-term harm, and the amount of longterm harm
was unknown. On the basis of the lack of evidence for
benefit, and the increased harm, the guideline group made a
strong recommendation against cannabinoids in general
(including pharmaceutical preparations) for rheumatic pain.
Further, in patients in whom cannabinoids were being
considered, there was a strong recommendation against
medical cannabis (particularly smoked) over pharmaceutical
cannabinoids. There is a high risk of bias in studies of smoked
cannabis, with unknown longterm consequences.
DISCUSSION
The reality of medical cannabis use in Canada. In accordance
with the lack of evidence for the effect of medical cannabis
in rheumatic diseases, the simplistic response, as endorsed
by others, is to recommend against use pending more
evidence6. The reality is that patients are requesting infor-
mation, may be considering use, or may be currently
self-medicating. Physicians may also have personal biases
regarding medical cannabis, either positive or negative.
Further, the Canadian legalization of recreational cannabis
allows freer access to cannabis by patients. Rheumatologists
therefore have an obligation to provide competent advice.
Physicians should understand the reason for consideration
of medical cannabis: relief of pain, sleep difficulties, or mood
disorders; poor effect of current treatments; perception of a
natural treatment; and encouragement by friends or family
members to use. Another prevailing argument is that medical
cannabis is safer than traditional analgesic drugs (i.e.,
opioids)12. Almost one-fifth of rheumatology patients are
currently using opioids, although not guideline-recommended
for rheumatic pain13,14. Considering fatalities associated with
opioids and absence of respiratory suppression by cannabi-
noids, medical cannabis may be a safer choice. Inserted into
this context must be the extensive media coverage of medical
cannabis, almost always favorable, and the constantly
associated anecdotes of outstanding effect. Subtle marketing
strategies buoyed by financial interests cannot be sufficiently
emphasized. In this highly charged climate, rheumatologists
must maintain an empathetic therapeutic relationship with
their patients, avoid personal biases, and ensure harm
reduction for both patients and society.
Position statement from the CRA for medical cannabis in
rheumatology patients. Given the lack of evidence for
medical cannabis for rheumatic complaints, but faced with
escalating access among patients, the CRA suggests the
following overarching principles (Table 1). Patients should be
informed that medical cannabis is not an alternative to
standard care for any rheumatic disease and that evidence for
the effect in rheumatic diseases is lacking. Short-term adverse
events including immediate psychomotor effects, dizziness,
appetite changes, effect on mood, and the rare serious side
effects of disorientation and psychosis are high, and longterm
risks are not yet known. Rheumatologists should adhere to
current treatment standards and guidelines for rheumatic
disease management and should maintain an empathetic thera-
peutic relationship with their patients, avoid personal biases,
and ensure harm reduction for both patients and society.
2The Journal of Rheumatology 2019; 46:doi:10.3899/jrheum.181120
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Putting principles into practice. Treatment principles to
reduce harm are outlined in Table 2. In line with good
medical practice, physicians must adhere to standard of care
when prescribing medical cannabis15. Beginning with a clear
understanding of the symptoms requiring treatment, attention
should be given to previous treatment trials, including
nonpharmacologic measures. Standard therapeutic options
should be accessed prior to consideration of medical
cannabis.
A prescription should only be provided by a physician
who is fully knowledgeable of the patient and is responsible
for patient care. Cannabis should not be prescribed following
online consultation or by those who project themselves as
“cannabis experts” focusing only on prescription of cannabis
without attention to global patient care. A formal distance
consultation requested by, and in collaboration with, the
treating physician may be considered for patients in distant
locations. The medical encounter must include documen-
tation of the medical condition, reason for medical cannabis
consideration, associated comorbidities, current medications,
and previous treatment trials. A psychosocial history must
include an assessment of mental health status, including past
or present psychosis or substance use disorder. A treatment
trial with a pharmaceutical product before consideration of
medical cannabis, although recommended, is often not a
practical consideration owing to difficulties with access and
cost.
Following consideration of potential benefits versus harm,
and when a decision is made to initiate a treatment trial, the
prescribing physician must assume responsibility for
followup. The goals of treatment should be clearly specified
and be realistic [e.g., a 30% symptom relief (pain, sleep, and
mood problems) and/or individually defined relevant
improvement of daily functioning]. Some physicians may
choose to complete a written treatment contract. Followup
should be within 4–8 weeks to evaluate efficacy and side
effects. Treatment should be initiated slowly, beginning with
a nighttime dose, and not exceeding 3 g/day, the maximum
average dose reported by medical cannabis users16. Cannabis
should be obtained legally from a registered grower
following submission of a prescription with known molecular
content of THC and CBD, and patients and physicians must
adhere to the legal requirements in their geographic region.
Some authors have suggested a maximum of 9% THC
concentration17. The treatment trial for a period of about 4–12
weeks may result in discontinuation of the product if
ineffective or if there are unwanted side effects.
Cannabis should not be smoked because of the toxic
products of combustion. Inhalation through a vaporizer is
preferred because less intensive heating reduces release of
toxic combustion products. Inhaled cannabis, through a
vaporizer, will give effects within a few minutes, with effects
3
Fitzcharles, et al: Medicinal cannabis in rheumatic disease
Pers onal non -com merc ial use only. The Journal of Rheumatology Copyright © 2019. All rights reserved.
Table 1. Overarching principles for medical cannabis in rheumatology patients.
1. Medical cannabis is not an alternative to standard care for any rheumatic disease, and rheumatologists should adhere to current treatment standards and
guidelines for rheumatic disease management.
2. There are no published studies of the effects of medical cannabis in patients with rheumatic diseases, and the few studies examining cannabinoid pharma-
ceutical products report limited benefits and high risk of adverse events.
3. Medical cannabis should not be used in rheumatology patients under the age of 25 years.
4. It is acknowledged that rheumatic disease patients may seek advice regarding use of medical cannabis, may currently be self-medicating with medical
cannabis, or may request a prescription for medical cannabis.
5. Common reasons that patients may consider use of medical cannabis are for pain relief and/or sleep promotion.
6. Current treatment strategies for pain relief and sleep promotion including non-pharmacologic treatments must be tried before consideration of use of
medical cannabis.
7. Medical cannabis may provide symptom relief for some patients with rheumatic diseases.
8. Short-term adverse events (including immediate psychomotor effects, dizziness, appetite changes, and effect on mood, and the rare serious side effects
of disorientation and psychosis) are frequent with the use of medical cannabis and are likely to be similar to those reported for other disease populations.
9. The longterm risks associated with medical cannabis use in patients with rheumatic diseases are unknown.
10. Despite a patient’s understanding of the lack of any scientific evidence to support a benefit, and the increased risk of harm, some patients may prefer a
trial of medical cannabis over other options, including opioids.
11. Rheumatologists must endeavor to maintain an empathetic therapeutic relationship with their patients, avoid personal biases, and ensure harm reduction
for both patients and society.
12. There is an urgent need for further research regarding the effects of medical cannabis in rheumatic diseases.
Table 2. Treatment principles to reduce harm.
Prior to starting medical herbal cannabis
Treatment goals and objectives should be realistic and clearly specified.
An assessment for substance use disorder must be documented.
Patients should be well informed about the adverse effects associated
with cannabis use.
Drug preparations, route of administration, and dosing
Inhalation through a vaporizer has a rapid therapeutic effect, whereas
oral ingestion has a slower but more sustained effect. Both routes of
administration are preferred over smoked cannabis.
Cannabis with a low THC content (maximum 9%) and higher CBD
content is preferable.
Total daily dose should not exceed 3 g.
The drug can be used regularly or on demand.
Assessment of side effects and efficacy
Followup 4–8 weeks after initiating the drug
Followup every 3 months thereafter
THC: Δ9-tetrahydrocannabinol; CBD: cannabidiol.
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lasting up to a few hours, although the psychoactive and
motor effects may last for over 24 h16. The effects of ingested
cannabis will occur more slowly and be more prolonged, and
may be the preferred method of administration for a treatment
regimen. Although there is no evidence to support the thera-
peutic effect of various concentrations of THC and CBD in
the herbal product, cannabis with a low THC content and
higher CBD content is preferable because there will be fewer
and less severe THC-induced psychoactive effects. Studies
to date have reported on THC content up to 12.5%, but with
a high rate of adverse events at this concentration18.
The ideal dosing schedule for medical cannabis is
unknown, with no dose-finding studies to examine optimal
daily amount or specific molecular concentrations of THC
and CBD6. Some patients may choose “on-demand” use
rather than regular use, but there is no evidence to support
this method. It is conceivable that ingested cannabis could
provide a more sustained effect, and that on-demand
inhalation could be used as a breakthrough measure.
However, on-demand use could lead to progressive increased
use and misuse.
Patients reporting benefit should be followed at least every
3 months, with assessment of efficacy as well as need for
continued treatment. Medical cannabis is ideally not a
lifetime treatment, and at each visit justification for continued
treatment must be documented. Physicians may choose to
request a urine drug screen for patients taking continuous
cannabis treatment as a caution to ensure that cannabis is not
being used as a concomitant recreational product, or that the
prescribed cannabis is not being diverted if there is
reimbursement for the medical product.
Risks applicable to all rheumatic disease patients using
medical cannabis. The risks associated with medical cannabis
have not been specifically examined in patients with
rheumatic diseases. Extrapolation from risks reported for
other medical conditions as well as from recreational users
is currently the only reasonable means to help inform clinical
care.
1. Smoking of herbal cannabis
Cannabis should not be smoked. Inhalation of combustible
products carries a risk of bronchial irritation19. Attenuation
of the protective respiratory tract mucosa will promote entry
of foreign antigens that have immunological effects that
influence the expression of inflammatory arthritis20. Similar
to the smoking of cigarettes, smoked cannabis may adversely
affect rheumatic diseases, but remains to be examined. The
risk for lung cancer and smoked cannabis remains unclear21.
2. Psychomotor effects
Psychomotor function is affected by cannabis in young recre-
ational users for up to 5 h after use22. This effect may be
prolonged for as long as 24 h when cannabis is ingested.
Driving after cannabis use is a risk for a collision, with risk
increased with dose of cannabis and further increased when
combined with alcohol23. In a metaanalysis of 9 studies
(49,411 subjects), Asbridge and colleagues reported a pooled
motor vehicle collision risk of 1.92 (95% CI 1.35–2.73,
p = 0.0003)24. Therefore, in line with recommendations of
Health Canada, patients using medical cannabis should be
warned not to drive or operate machinery for at least 24 h
after consumption, with possible effects prolonged in the
presence of other agents affecting psychomotor function such
as tranquilizers, antidepressants, anti-epileptic drugs, and
opioids16. Self-report that a patient experiences no
psychomotor effects is not sufficient reason to ignore this risk
and requires formal evaluation (e.g., a formal test of driving
ability).
3. Risks of addiction
Cannabis is an addictive substance25. Regular recreational
cannabis use is associated with a risk of addiction estimated
to be about 9% for all users, but with increased rates for
younger age of onset of use, regular daily use, and likely
increased concentration of THC. Addiction risk is not known
for medical cannabis use but is unlikely to be different from
that observed for recreational users. It is prudent to reflect on
the evolution of the 1980s concept that opioid treatment for
chronic pain would not be associated with addiction; that
concept is now completely overturned26.
4. Interactions of cannabinoids with other medications
Information regarding interactions of herbal cannabis and
other drugs is limited. It can be anticipated that the
psychomotor effects of drugs, such as tranquilizers, anti -
depressants, anticonvulsants, and also alcohol, will be
augmented with cannabis and should be avoided or used with
caution. In a study of smoked cannabis in patients with
chronic pain, with almost two-thirds of the subjects treated
concomitantly with opioids, the rate of serious adverse events
was over 20 per 100 patient-years, an alarmingly high rate
that is greater than many rheumatology drug treatments18.
Contraindications and cautions for medical cannabis use.
Attention should be given to the use of medical cannabis for
certain patient populations (Table 3).
4The Journal of Rheumatology 2019; 46:doi:10.3899/jrheum.181120
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Table 3. Contraindications and cautions for medical cannabis.
Populations in which medical cannabis should not be used
Rheumatology patients under the age of 25 years
Patients with allergic reactions to cannabinoid products
Women who are pregnant or breastfeeding
Patients with a history of a psychotic illness, substance abuse disorder,
previous suicide attempts, or suicidal ideation
Populations in which medical cannabis should be used with caution
Elderly patients
Patients with unstable mental health disease
Patients with a history of current moderate or severe cardiovascular or
pulmonary disease
Patients working in settings requiring high levels of concentration,
optimal executive functioning, and alertness
Patients receiving concomitant therapy with sedative-hypnotics or other
psychoactive drugs
Journal of Rheumatology The on January 19, 2019 - Published by www.jrheum.orgDownloaded from
1. Young persons
Herbal cannabis should not be used by patients under the age
of 25 years, in line with the Canadian Paediatric
Association17,27. Brain development continues until the early
20s, with the cannabinoid system playing a critical role28.
Cannabis use at a young age adversely affects psychosocial
development, academic and social attainment, and is a risk
for mental health disease29,30. There are no studies examining
the above effects related to various concentrations of THC
and CBD in the herbal product, although concentration of
THC in street cannabis has increased exponentially in the last
2 decades, from 3% to a current 25–30%31,32. Young patients
self-medicating with a recreationally acquired product should
be cautioned about this increased concentration of THC and
the associated increased risk of cognitive and psychoactive
effects. Microbial contamination of the street product is also
a risk for patients who may be immunocompromised.
2. Pregnant and lactating women
Cannabis should be avoided in women during pregnancy and
lactation. The endocannabinoid system is critical in normal
brain development, although effect on the human fetus is
unclear. THC crosses the placenta in rat studies, with appre-
ciable levels measured in the pups, and associated transient
and permanent behavioral effects33. There is transfer of
cannabinoids into breast milk, with cannabinoid metabolites
excreted by both animal and human offspring34.
3. Those hypersensitive to cannabis
Allergic sensitization with the development of specific
immunoglobulin E can occur through inhalation, oral
ingestion, or cutaneous contact with cannabis. Depending on
the route of exposure, hypersensitivity reactions can vary
widely and range from mild cutaneous or respiratory
symptoms to angioedema and anaphylaxis35. Because of the
potential for life-threatening reactions, strict avoidance
measures should be enforced for patients with suspected or
confirmed cannabis allergy36.
4. Older persons
Medical cannabis has had limited study in the elderly. In an
Israeli study of patients over 65 years, with one-third of the
original 2736 persons followed for 6 months, there was
reduction of pain and discontinuation or reduction of opioid
doses in 18%37. The potential risks associated with medical
cannabis in the elderly include effects on cognitive function
and motor coordination, risk of confusion, and falls and
injury. Psychomotor impairment is well described in young
recreational users, but although not evaluated in the elderly,
is likely to be at least similar but probably more
pronounced22. Impairments in reaction time, selective
attention, short-term memory, and motor control will criti-
cally affect the well-being of older persons. Additional
potential risks not yet examined are the effects of drug inter-
actions and comorbid illnesses, especially cardiac and
pulmonary diseases. Drug interactions can reasonably be
expected to be compounded by cannabis, especially those
affecting cognition, motor control, or mood. Therefore,
extreme caution should be exercised when an elderly patient
anticipates use of medical cannabis.
5. The working patient
Cannabis has psychoactive properties and affects motor
function; therefore, competence in the work environment is
critical. Higher concentrations of THC are associated with
greater effect on cognition and psychomotor activity,
although even a low concentration may have appreciable
effects for some22. Patient self-report of competence is
unreliable. In the absence of any formal standard of testing,
patients should be informed that cognitive function will likely
be impaired, although perhaps not perceptibly, and that any
use of cannabinoids should be avoided in settings requiring
concentration, optimal executive functioning, and alertness.
This is particularly true for settings where impairment of
cognition may pose a threat to others.
6. Those with comorbid illness
a. Mental health disease
Cannabis should generally be avoided in persons with a
history of mental health disease, with an absolute contraindi-
cation for persons with a personal or family history of a
psychotic illness, a history of substance abuse disorder,
previous suicide attempts, or suicidal ideation38. According
to the comprehensive publication on the health effects of
cannabis and cannabinoids by The National Academies of
Sciences, Engineering, and Medicine, there is an absence of
evidence to support or refute cannabis-induced changes in
the course of depressive disorders, but moderate evidence for
increased suicidal ideation, suicide attempts, and suicide
completion38. For anxiety, there is limited evidence of an
association of daily cannabis use and development of any
type of anxiety disorder, except social anxiety, and limited
evidence for increased symptoms of anxiety in those with a
previous anxiety state38. Therefore in this context of uncer-
tainty, it is prudent to be cautious when counseling patients
with mental health disorders on the use of cannabis, and in a
case of uncertainty, referral for psychiatric evaluation should
be considered. Therefore, the CRA suggests a relative
contraindication in persons with mental health disorders
including anxiety and depression, with a warning that mood
disorders may be aggravated by cannabis. Although cannabis
is mostly anxiolytic, paradoxically anxiety may be increased
and depressive symptoms aggravated. Although cannabis is
widely advocated for effect on posttraumatic stress disorder,
the current evidence is limited to anecdotes, case reports, and
observational studies39. Clinical judgment should be used to
assess the risk of medical cannabis in current recreational
users. There should be an assessment of addiction risk and
severity of symptoms requiring treatment, and as much as
possible, distinction made between recreational and
medicinal use. If medical cannabis is used, treatment should
ideally be in collaboration with a psychiatrist.
b. Cardiovascular disease and pulmonary disease
5
Fitzcharles, et al: Medicinal cannabis in rheumatic disease
Pers onal non -com merc ial use only. The Journal of Rheumatology Copyright © 2019. All rights reserved.
Journal of Rheumatology The on January 19, 2019 - Published by www.jrheum.orgDownloaded from
Cannabis should not be used in patients with moderate or
severe cardiovascular or pulmonary disease40,41. Because
cannabis increases heart rate, blood pressure, and myocardial
oxygen demand, use may aggravate stable angina or trigger
myocardial infarction. Daily cannabis use increases the
annual risk of myocardial infarction from 1.5% to 3% per
year. Cardiovascular events, including sudden cardiac death,
vascular events (coronary, cerebral, and peripheral), and
arrhythmias are increasingly reported in young recreational
users without other risk factors, suggesting that older persons
with preexisting disease are at even greater risk42. Smoked
cannabis is associated with chronic bronchitis symptoms, but
case-controlled studies have not identified an association with
lung cancer40.
Much remains unknown regarding medical cannabis use
in rheumatic diseases, including true efficacy as well as risks
(Table 4). Rheumatologists can play an important role in (1)
ensuring patients are educated regarding what is currently
known concerning potential risks versus benefits of medical
cannabis, and (2) providing patient-centered counseling for
those who are taking or planning to take cannabis, with a goal
toward harm reduction. Whether medical cannabis will
finally emerge as a standard treatment option for our patients
remains to be seen.
ACKNOWLEDGMENT
The authors thank the Canadian Rheumatology Association Therapeutics
Committee members: Kenneth Blocka, Claire Bombardier, Sasha Bernatsky,
Jeff Gong, Adam Huber, Michelle Jung, Janet Pope, Rosie Scuccimarri,
J. Carter Thorne, Peter Tugwell, and Michael Wodkowski.
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Pers onal non -com merc ial use only. The Journal of Rheumatology Copyright © 2019. All rights reserved.
Table 4. Key points associated with use of medical cannabis.
Medical cannabis is defined as the leaves and flowers of the plant family
Cannabaceae.
Cannabis comprises many molecules, of which Δ9-tetrahydrocannabinol
(THC) and cannabidiol (CBD) are the most studied for therapeutic effect.
THC is associated with psychoactive effects whereas CBD is likely to have
pain- and inflammatory-modulating effects.
Herbal cannabis has THC content varying from < 1% to 24% and CBD
content from < 1% to 13%.
There are no studies examining the efficacy of whole plant herbal cannabis
(i.e., medical cannabis) in patients with rheumatic disease.
Studies examining cannabinoid pharmaceutical products reveal limited
benefits and high risk of adverse events.
Patients considering use of medical cannabis should be warned not to drive
or operate machinery for at least 24 h after consumption.
Patients should be warned that their function may be compromised when
working in settings requiring high levels of concentration, optimal executive
functioning, and alertness.
Regular recreational cannabis use is associated with a risk of addiction, but
this risk has not been assessed in medical cannabis users.
Concomitant use of medical cannabis and tranquilizers, antidepressants,
anticonvulsants, or alcohol should be avoided.
Journal of Rheumatology The on January 19, 2019 - Published by www.jrheum.orgDownloaded from
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28. Harkany T, Keimpema E, Barabas K, Mulder J. Endocannabinoid
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development. Mol Cell Endocrinol 2008;1-2 Suppl 1:S84-90.
29. Meier MH, Caspi A, Ambler A, Harrington H, Houts R, Keefe RS,
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35. Decuyper I, Ryckebosch H, Van Gasse AL, Sabato V, Faber M,
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36. Decuyper I, Van Gasse AL, Cop N, Sabato V, Faber MA, Mertens C,
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2017;72:201-6.
37. Abuhasira R, Schleider LB, Mechoulam R, Novack V.
Epidemiological characteristics, safety and efficacy of medical
cannabis in the elderly. Eur J Intern Med 2018;49:44-50.
38. National Academies of Sciences, Engineering, and Medicine. The
health effects of cannabis and cannabinoids: The current state of
evidence and recommendations for research. Washington, DC: The
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40. Tashkin DP. Marijuana and lung disease. Chest 2018;154:653-63.
41. Franz CA, Frishman WH. Marijuana use and cardiovascular disease.
Cardiol Rev 2016;24:158-62.
42. Singh A, Saluja S, Kumar A, Agrawal S, Thind M, Nanda S, et al.
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7
Fitzcharles, et al: Medicinal cannabis in rheumatic disease
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