This document has been prepared by the CFPC to provide preliminary, rather than comprehensive, guidance, based on what is currently known about the use of cannabis for certain medical purposes. Dried cannabis is not an approved drug or medicine in Canada, and the provision of this information should not be interpreted as an endorsement of the use of this product, or of cannabis generally, by the CFPC. The content within this document is provided for information and education purposes about a new and largely unstudied area of clinical practice. It is not intended to substitute for the advice of a physician. Patients should always consult their doctors for specific information on personal health matters, or other relevant professionals to ensure that their own circumstances are considered. The CFPC accepts no responsibility or liability arising from any error or omission or from the use of any information contained herein. Reproduction of the CFPC logo or hyperlinking to this document for commercial purposes is strictly prohibited.The College of Family Physicians of Canada welcomes your feedback. We are working to ensure that the recommendations in this guidance document continue to reflect the latest available evidence and to incorporate the practice expertise of CFPC members who use them. If you have suggestions for additions or changes to this document, we would appreciate receiving them. All feedback received will be considered for inclusion in the revised guide, to be released Winter 2015.# Introduction
The Health Canada Marihuana for Medical Purposes Regulations (MMPR), 1 which came into force on April 1, 2014, permit a physician to sign a medical document authorizing a patient's access to, and the dispensing of, a specified quantity of the dried cannabis plant, which patients purchase through a licensed producer. The medical document has a format and function similar to a prescription. However, dried cannabis differs from prescribed products in that Health Canada has not reviewed data on its safety or effectiveness and has not approved it for therapeutic use. This situation puts family physicians in a difficult position: we are asked to authorize our patients' access to a product with little evidence to support its use, and in the absence of regulatory oversight and approval.
To address this predicament, this document offers family physicians preliminary guidance on the authorizing of dried cannabis for chronic pain or anxiety, pending the development of formal guidelines. Although the MMPR speak only of use for medical purposes without specifying any diagnoses, the writing group chose chronic pain and anxiety as the clinical areas to highlight because they may be the most common conditions for which a patient requests authorization for cannabis from a family physician.
Research shows that dried cannabis is a potent, psychoactive substance that can have significant acute and chronic cognitive effects. Its acute effects include perceptual distortions, cognitive impairment, euphoria, and anxiety. 2 Chronic use of dried cannabis may be associated with persistent neuropsychological deficits, even after a period of abstinence. The patient may report initial benefit from smoking cannabis and, as with many mood-altering substances such as alcohol, opioids, benzodiazepines, and cocaine, experience temporary relief from pain or anxiety. However, these products have the potential to cause harm by impairing memory and cognition, worsening performance at work and school, and by interfering with social relationships. Before authorizing cannabis, family physicians need to consider if there is sufficient evidence that the anticipated therapeutic benefits for the patient's particular health condition outweigh the potential harms. Similarly, continuation of the cannabis is warranted only if the authorizing physician is satisfied that there has been improvement in the patient's pain level, function, and/or quality of life, and that there are no signs that the patient is at risk of misuse or harm.
This document was written by members of the Addiction Medicine and Chronic Pain Program Committees of the Section of Family Physicians with Special Interests or Focused Practices (SIFP) of the College of Family Physicians of Canada (CFPC), in collaboration with other individuals and SIFP Program Committees: Child and Adolescent Health, Maternity and Newborn Care, Mental Health, Palliative Care, and Respiratory Medicine. CFPC Program Committees are made up of members with a special interest, and often enhanced expertise, in a specific clinical domain that is relevant to the practice of family medicine.
The writing team based the document on a literature search and review of evidence on specific topics related to cannabis effectiveness, safety, and adverse effects. The team acknowledges the research of Kahan and colleagues, which has been adapted in the preparation of this document. The material appears with the permission of the publisher, Canadian Family Physician.
Members of the participating program committees collaborated to prepare a succession of drafts, which then underwent review by an editorial team. A subgroup of the editorial team wrote the final document on behalf of the participants. The final document was taken to the entire group for its consensus before publication.
Recommendations were graded as Level I (based on well-conducted controlled trials or meta-analyses), Level II (well-conducted observational studies), or Level III (expert opinion; for the purposes of this document, consensus among the committee members drafting this document on behalf of the CFPC).
The context within which the participants worked to produce this document is extraordinary, as we have described above: authorization of a largely unstudied substance, particularly challenging medical practice areas (pain and addiction), intense interest from patients (often accompanied by less interest in evidence), an absence of regulation, and, above all, an urgency to provide basic parameters to guide family physicians in the safe treatment of their patients.
The individuals named in the Acknowledgements agreed to be listed as contributors on the basis that this document:
- Was urgently needed to address a knowledge gap in a controversial practice area without the usual supports and
- Provides preliminary guidance while the CFPC engages in a rigorous process to provide more formal clinical practice guidelines and continuing professional development offerings

# How to navigate this document
This document is organized into two parts. The first, "A. Summary of Recommendations," outlines the recommendations in brief, sketching in point form the new and still developing landscape within which family physicians find themselves regarding "medical marijuana":
- The federal regulations that give the physician the responsibility for granting access to this unregulated substance - The as-yet limited evidence regarding cannabis's effects and efficacy in clinical use - The degree to which evidence derived from studies of pharmaceutical cannabinoids can be applied to dried cannabis, and vice versa - The provincial medical regulatory authorities' requirements of physicians regarding signing medical documents for cannabis - The issues and questions that arise in the sometimes challenging conversations between physicians and patients surrounding cannabis
The second part, "B. Discussion and Supporting Evidence," provides a fuller discussion of these topics. It describes:
- What we know to date about the potential harms and benefits of cannabis use in various populations and for treating different conditions, with a focus on pain and anxiety - Regulations and suggested best practices to follow before authorizing and continuing a patient's access to cannabis
It also provides practical resources to use in clinical practice, including:
- Messages for patients - Tools to use when screening patients for misuse or addiction risk - A sample treatment agreement - Information about the strains available from licensed producers - Calculations for dosing
In sections A and B, the recommendations are grouped under the headings:
- General principles (recommendations 1-6)
- Misuse prevention and intervention (recommendation 7)
- Assessment, monitoring, and discontinuation (recommendations 8 and 9)
- Strategies to prevent harm (recommendations 10 and 11)
- Communication with patients and consultants (recommendations 12 and 13)
- Dosing (recommendations 14 and 15)

# A. Summary of Recommendations
To navigate to the discussion and evidence for an individual recommendation, click on the hyperlinked heading.

# General principles Recommendation 1
There is no research evidence to support the authorization of dried cannabis as a treatment for pain conditions commonly seen in primary care, such as fibromyalgia or low back pain (Level III). Authorizations for dried cannabis should only be considered for patients with neuropathic pain that has failed to respond to standard treatments (Level I).

# Recommendation 2
If considering authorizing dried cannabis for treatment of neuropathic pain, the physician should first consider a) adequate trials of other pharmacologic and nonpharmacologic therapies and b) an adequate trial of pharmaceutical cannabinoids (Level I).

# Recommendation 3
Dried cannabis is not an appropriate therapy for anxiety or insomnia (Level II).

# Recommendation 6
Physicians should follow the regulations of their provincial medical regulators when authorizing dried cannabis (Level III).

# Misuse prevention and intervention Recommendation 7
Physicians should assess and monitor all patients on cannabis therapy for potential misuse or abuse (Level III).

# Assessment, monitoring, and discontinuation Recommendation 8
Before signing a medical document authorizing dried cannabis for pain, the physician should do all of the following:

# Recommendation 9
The physician should regularly monitor the patient's response to treatment with dried cannabis, considering the patient's function and quality of life in addition to pain relief (Level III). The physician should discontinue authorization if the therapy is not clearly effective or is causing the patient harm (Level III).

# Strategies to prevent harm Recommendation 10
Patients taking dried cannabis should be advised not to drive for at least:

# Recommendation 11
When authorizing dried cannabis therapy for a patient, the physician should advise the patient of harm reduction strategies (Level III).

# Communication with patients and consultants Recommendation 12
The physician should manage disagreements with patients about decisions around authorization, dosing, or other issues with unambiguous, evidence-based statements (Level III).

# Recommendation 13
The physician who is authorizing cannabis for a particular clinical indication must be primarily responsible for managing the care for that condition and following up with the patient regularly (Level III). Physicians seeking a second opinion on the potential clinical use of cannabis for their patient should only refer to facilities that meet standards for quality of care typically applied to specialized pain clinics (Level III). In both instances, it is essential that the authorizing physician, if not the patient's most responsible health care provider, communicate regularly with the family physician providing ongoing comprehensive care for the patient (Level III).

# Dosing Recommendation 14
Given the weak evidence for benefit and the known risks of using cannabis, the only sensible advice for physicians involved with authorizing dried cannabis is the maxim "Start low, and go slow" (Level III).

# Recommendation 15
Although it is not required by the MMPR, physicians should specify the percentage of THC on the medical document for all authorizations for dried cannabis, just as they would specify dosing when prescribing any other analgesic (Level III).

# B. Discussion and Supporting Evidence

# RECOMMENDATION 1
There is no research evidence to support the authorization of dried cannabis as a treatment for pain conditions commonly seen in primary care, such as fibromyalgia or low back pain (Level III). Authorizations for dried cannabis should only be considered for patients with neuropathic pain that has failed to respond to standard treatments (Level I).
To date, five controlled trials have examined dried cannabis in the treatment of chronic neuropathic pain.  The trials were small, included patients who had previously smoked cannabis, and lasted from 1 to 15 days. Functional status, quality of life, and other important outcomes were not measured. No head-to-head comparisons of therapeutic benefits or adverse effects were made with other standard treatments for these conditions, or with pharmaceutical cannabinoid preparations.
The safety and effectiveness of dried cannabis has not been studied for pain conditions such as fibromyalgia and low back pain. No controlled studies have been conducted on dried cannabis for osteoarthritis, and the Canadian Rheumatology Association does not endorse the use of dried cannabis for either fibromyalgia or osteoarthritis. 12 The oral pharmaceutical cannabinoid nabilone has some evidence of benefit for these conditions, although the evidence is weaker than for first-line treatments. 13,14 Family physicians are advised to recommend other treatments with more evidence of safety and efficacy for these conditions.

# RECOMMENDATION 2

# If considering authorizing dried cannabis for treatment of neuropathic pain, the physician should first consider a) adequate trials of other pharmacologic and nonpharmacologic therapies and b) an adequate trial of pharmaceutical cannabinoids (Level I).
There are many pharmacologic and nonpharmacologic treatments documented as effective in the treatment of neuropathic pain, and these established therapies should be tried before moving on to trials of cannabinoids. Oral and buccal pharmaceutical cannabinoids have a larger body of evidence of efficacy than has dried cannabis in the treatment of neuropathic pain,  although, apart from Sativex (indicated for neuropathic pain associated with multiple sclerosis or cancer), these drugs' use for this treatment is off label. Evidence suggests that oral cannabinoids are also safer, with a lower risk of addiction and with milder cognitive effects. 19, However, until further research is conducted, the same contraindications and precautions that apply to dried cannabis apply to pharmaceutical cannabinoids. Patients who request cannabis but refuse a trial of pharmaceutical cannabinoids may be using cannabis for euphoria rather than analgesia.

# RECOMMENDATION 3

# Dried cannabis is not an appropriate therapy for anxiety or insomnia (Level II).
To our knowledge, there have been no controlled studies to date on the use of dried cannabis in the treatment of anxiety disorders. There is, however, a strong and consistent association between cannabis use and anxiety and mood disorders, although causality has not been established.  Acute cannabis use can trigger anxiety and panic attacks, 39 and studies on animals and human volunteers suggest that high doses of cannabis actually worsen anxiety. 40 Cannabis use may worsen psychiatric impairment in patients with anxiety disorders. 36,41,42 The tetrahydrocannabinol (THC) content of cannabis is associated with anxiety, 41 though this relationship appears to be bidirectional. 43,44 Physicians should consider the THC content of available cannabis and consider authorizing, if at all, only lower-strength strains for patients with anxiety. 45 Regular users of cannabis might experience early symptoms of cannabis withdrawal, including an exacerbation of anxiety, when they abstain; withdrawal symptoms can ultimately be resolved through cannabis cessation. 46 The evidence for using pharmaceutical cannabinoids in the treatment of anxiety and insomnia is stronger than the evidence for using dried cannabis. Small trials have demonstrated that oral nabilone improves sleep in patients with fibromyalgia or post-traumatic stress disorder. 13,47 An oral extract of pure cannabidiol has been shown to relieve symptoms of social anxiety. 48

# RECOMMENDATION 4
Dried cannabis is not appropriate for patients who: Youth who smoke cannabis are at greater risk than older adults for cannabis-related psychosocial harms, including suicidal ideation, illicit drug use, cannabis use disorder, and long-term cognitive impairment. 4,33,

# Patients with current, past, or strong family history of psychosis (Level II)
Observational studies have demonstrated a consistent association between cannabis use in adolescence and persistent psychosis.

# Patients with current or past cannabis use disorder (Level III)
Pain patients with cannabis use disorder should be counseled to discontinue cannabis and be referred for addiction treatment.

# Patients with an active substance use disorder (Level III)
Dried cannabis should not be authorized for any patient with a current problematic use of alcohol, opioids, or other drugs.

# Patients with cardiovascular disease (Level III)
Cannabis use causes acute physiological effects such as hypertension, tachycardia, catecholamine release, and vascular constriction.  There have been reports of young people suffering cardiovascular events shortly after smoking cannabis.

# Patients with respiratory disease (Level III)
Heavy cannabis smoking may be an independent risk factor for impaired respiratory function and chronic obstructive pulmonary disease. 68,69 Use of smoked cannabinoids has been found to increase the risk of airflow obstruction and hyperinflation but has been less associated with macroscopic emphysema. 70 The cannabis use was associated with increased risk of lung cancer 71 The respiratory symptoms associated with dried cannabis use include wheezing apart from colds, exercise-induced shortness of breath, nocturnal wakening with chest tightness, and early morning sputum and head and neck cancer. 72 production. 73 The depth of inhalation and the length of time the breath is held are usually greater when smoking marijuana than when smoking cigarettes. This means exposure to the chemicals in the smoke is greater for cannabis than for tobacco cigarettes, even though the frequency of smoking may be less. Cannabis smokers, for example, end up with five times more carbon monoxide in their bloodstream than do tobacco smokers. 71

# Patients who are pregnant, planning to become pregnant, or breastfeeding (Level II)
Preliminary evidence links cannabis use during pregnancy to neurodevelopmental abnormalities in infants. 74 Cannabis enters the breast milk and is contraindicated in women who are breastfeeding.

# Patients with current mood and anxiety disorders (Level II)
Caution should be used when authorizing cannabis for patients with current mood or anxiety disorders, for the reasons outlined in If patients with co-existing anxiety and neuropathic pain are authorized for cannabis treatment, i) the dose should be kept low to avoid triggering anxiety, ii) the provider should consider indicating low THC-content or cannabidiol-only (CBD-only) strains on the medical document, and iii) cannabis should be discontinued if the patient's anxiety or mood worsens.

# Recommendation 3.

# Tobacco smokers (Level II)
Even after controlling for tobacco smoking, cannabis smoking has been associated with lung cancer 75 and chronic bronchitis. Patients who smoke tobacco should be strongly advised to use cannabis via vaporization rather than by smoking it.

# Patients with risk factors for cardiovascular disease (Level II)
Physicians are advised to use considerable caution when authorizing dried cannabis for use by patients with risk factors for cardiovascular disease (see. The dose should be kept low, and the patient should be encouraged to take it through vaporization or the oral route rather than by smoking it.

# Recommendation 4e

# Patients who are heavy users of alcohol, or taking high doses of opioids or benzodiazepines (Level III)
Cannabis use can worsen the cognitive impairment caused by opioids, benzodiazepines, other sedatives, and Patients taking dried cannabis should be advised to use alcohol in moderation, and physicians should consider tapering patients on high doses of opioids or benzodiazepines. alcohol. 76

# RECOMMENDATION 6
Physicians should follow the regulations of their provincial medical regulators when authorizing dried cannabis (Level III).
Many of the provincial/territorial regulatory bodies have released policies on the authorization of cannabis. 79 These regulators advise physicians to conduct a thorough assessment and to try conventional alternatives before providing a medical document for cannabis. Additional requirements, which vary considerably from province to province, are summarized below and in Table 1. Physicians should review the complete policy of their provincial regulator before signing a medical document for cannabis.