Medical cannabis Q&A

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  • “1. What is medical cannabis?

The term “medical cannabis” is used to describe products derived from the whole cannabis plant or its extracts containing a variety of active cannabinoids and terpenes, which patients take for medical reasons, after interacting with and obtaining authorization from their health care practitioner.

  • 2. What are the main active ingredients?

The chemical ingredients of cannabis are called cannabinoids. The 2 main therapeutic ones are:

  •  A Tetrahydrocannabinol (THC) is a partial agonist of CB1 and CB2 receptors. It is psychoactive and produces the euphoric effect.
  •  B Cannabidiol (CBD) has a weak affinity for CB1 and CB2 receptors and appears to exert its activity by enhancing the positive effects of the body’s endogenous cannabinoids
 3. Why do patients take it?

Medical cannabis may be used to alleviate symptoms for a variety of conditions. It has most commonly been used in neuropathic pain and other chronic pain conditions. There is limited, but developing, clinical evidence surrounding its safety and efficacy, and it does not currently have an approved Health Canada indication.

  • 4. How do patients take it?

Cannabis can be smoked, vaporized, taken orally, sublingually, topically or rectally. Different routes of administration will result in different pharmacokinetic and pharmacodynamic properties of the drug.

  • 5. Is it possible to develop dependence on medical cannabis?

Yes, abrupt discontinuation after long-term use may result in withdrawal symptoms. Additionally, chronic use may result in psychological dependence.

  • 6. What is the difference between medical and recreational cannabis?

Patients taking cannabis for medical reasons generally use cannabinoids to alleviate symptoms while minimizing intoxication, whereas recreational users may be taking cannabis for euphoric effects. Medical cannabis is authorized by a prescriber who provides a medical document allowing individuals to obtain cannabis from a licensed producer or apply to Health Canada to grow their own, whereas recreational cannabis is currently obtained through illicit means.

  • 7. How can patients access cannabis for medical purposes?
  • 8. Does medical cannabis have a DIN?

Pharmacological cannabinoids such as Sativex (delta-9-tetrahydrocannabinol-cannabidiol) and Cesamet (nabilone) have been approved for specific indications by Health Canada, however, herbal medical cannabis has not gone through Health Canada’s drug review and approval process, nor does it have a Drug Identification Number (DIN) or Natural Product Number (NPN).

  • 9. Is medical cannabis covered through insurance?

Some insurance plans may cover medical cannabis. Check each patient’s individual plan for more details.

  • 10. What role can pharmacists play in medical cannabis?

Even though pharmacists are not dispensing medical cannabis at this time, it is important for them to understand how their patients may use and access medical cannabis in order to provide effective medication management. Pharmacists may provide counselling on areas such as contraindications, drug interactions, management of side effects, alternative therapies, potential addictive behaviour and appropriate use.

  • 11. Where can I find more information about medical cannabis?

You can find more information on Health Canada’s website:” https://www.canada.ca/en/health-canada/services/drugs-health-products/medical-use-marijuana/medical-use-marijuana.html

https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5661684/

Availability and approval of cannabis-based medicines for chronic pain management and palliative/supportive care in Europe: A survey of the status in the chapters of the European Pain Federation.

European Journal of Pain

“There is considerable public and political interest in the use of cannabis products for medical purposes.

METHODS:

The task force of the European Pain Federation (EFIC) conducted a survey with its national chapters representatives on the status of approval of all types of cannabis-based medicines, the covering of costs and the availability of a position paper of a national medical association on the use of medical cannabis for chronic pain and for symptom control in palliative/supportive care.

RESULTS:

Thirty-one out of 37 contacted councillors responded. Plant-derived tetrahydrocannabinol/cannabidiol (THC/CBD) oromucosal spray is approved for spasticity in multiple sclerosis refractory to conventional treatment in 21 EFIC chapters. Plant-derived THC (dronabinol) is approved for some palliative care conditions in four EFIC chapters. Synthetic THC analogue (nabilone) is approved for chemotherapy-associated nausea and vomiting refractory to conventional treatment in four EFIC chapters’. Eight EFIC chapters’ countries have an exceptional and six chapters an expanded access programme for medical cannabis. German and Israeli pain societies recommend the use of cannabis-based medicines as third-line drug therapies for chronic pain within a multicomponent approach. Conversely, the German medical association and a team of finish experts and officials do not recommend the prescription of medical cannabis due to the lack of high-quality evidence of efficacy and the potential harms.

CONCLUSIONS:

There are marked differences between the countries represented in EFIC in the approval and availability of cannabis-based products for medical use. EFIC countries are encouraged to collaborate with the European Medicines Agency to publish a common document on cannabis-based medicines.

SIGNIFICANCE:

There are striking differences between European countries in the availability of plant-derived and synthetic cannabinoids and of medical cannabis for pain management and for symptom control in palliative care and in the covering of costs by health insurance companies or state social security systems.”

https://www.ncbi.nlm.nih.gov/pubmed/29134767

http://onlinelibrary.wiley.com/doi/10.1002/ejp.1147/abstract

Pharmacokinetic and behavioural profile of THC, CBD, and THC+CBD combination after pulmonary, oral, and subcutaneous administration in rats and confirmation of conversion in vivo of CBD to THC.

European Neuropsychopharmacology Home

“Of central importance was the novel finding that THC can be detected in serum and brain after administration of CBD alone which, if confirmed in humans and given the increasing medical use of CBD-only products, might have important legal and forensic ramifications.” https://www.ncbi.nlm.nih.gov/pubmed/29129557  http://www.europeanneuropsychopharmacology.com/article/S0924-977X(17)30983-5/fulltext

Cannabidiol as a treatment for epilepsy

Journal of Neurology

“Despite an increasing number of anti-epileptic drugs (AEDs), the proportion of drug-resistant cases of epilepsy has remained fairly static at around 30% and the search for new and improved AEDs continues.

Cannabis has been used as a medical treatment for epilepsy for thousands of years; it contains many active compounds, the most important being tetrahydrocannabinol, which has psychoactive properties, and cannabidiol, which does not.

Animal models and clinical data to date have suggested that cannabidiol is more useful in treating epilepsy; there is limited evidence that tetrahydrocannabinol has some pro-convulsant effects in animal models. The mechanism by which cannabidiol exerts its anti-convulsant properties is currently unclear.

Conclusion. The evidence is increasing that cannabidiol is an effective treatment option for childhood onset severe treatment-resistant epilepsies with a tolerable side effect and safety profile. Further evidence is needed before cannabidiol can be considered in more common or adult onset epilepsies. Longer-term safety data for cannabidiol, particularly considering its effects on the developing brain, are also required.”

https://link.springer.com/article/10.1007%2Fs00415-017-8663-0

Single-Dose Pharmacokinetics of Oral Cannabidiol Following Administration of PTL101: A New Formulation Based on Gelatin Matrix Pellets Technology.

Clinical Pharmacology in Drug Development

“Cannabidiol (CBD) is the main nonpsychoactive component of the cannabis plant. It has been associated with antiseizure, antioxidant, neuroprotective, anxiolytic, anti-inflammatory, antidepressant, and antipsychotic effects.

PTL101 is an oral gelatin matrix pellets technology-based formulation containing highly purified CBD embedded in seamless gelatin matrix beadlets. Study objectives were to evaluate the safety and tolerability of PTL101 containing 10 and 100 mg CBD, following single administrations to healthy volunteers and to compare the pharmacokinetic profiles and relative bioavailability of CBD with Sativex oromucosal spray (the reference product) in a randomized, crossover study design.

Administration of PTL101 containing 10 CBD, led to a 1.7-fold higher Cmax and 1.3-fold higher AUC compared with the oromucosal spray. Tmax following both modes of delivery was 3-3.5 hours postdosing. CBD exhibited about a 1-hour lag in absorption when delivered via PTL101. A 10-fold increase in the dose resulted in an ∼15-fold increase in Cmax and AUC. Bioavailability of CBD in the 10-mg PTL101 dose was 134% relative to the reference spray.

PTL101 is a pharmaceutical-grade, user-friendly oral formulation that demonstrated safe and efficient delivery of CBD and therefore could be an attractive candidate for therapeutic indications.”

https://www.ncbi.nlm.nih.gov/pubmed/29125702

http://onlinelibrary.wiley.com/doi/10.1002/cpdd.408/abstract

Efficacy and safety of cannabis for treating children with refractory epilepsy.

Nursing Children and Young People

“The aim of this literature review was to examine the evidence base for the safety and efficacy of cannabis in treating children with refractory epilepsy. Clinical and medical databases were searched and four articles were included in the final analysis, which included retrospective reviews and open-label trials with a total sample size of 424. One clinical trial included administration of cannabidiol, the non-psychoactive compound of cannabis, while the other three articles stated that the compound administered to participants contained tetrahydrocannabidiol, the psychoactive constituent of cannabis.

Cannabis may reduce seizures in some children and young people with refractory epilepsy, however, its success may be affected by aetiology of the epilepsy or concomitant anti-epileptic drug use, and a therapeutic dose has not been found. Positive side effects were also found including improved sleep, alertness and mood. More research is needed on this subject, including randomised controlled trials. Nurses who are aware of patients and families wishing to trial cannabis for refractory epilepsy should have full and frank discussions.”

https://www.ncbi.nlm.nih.gov/pubmed/29115760

https://journals.rcni.com/nursing-children-and-young-people/efficacy-and-safety-of-cannabis-for-treating-children-with-refractory-epilepsy-ncyp.2017.e907

Binding and Signaling Studies Disclose a Potential Allosteric Site for Cannabidiol in Cannabinoid CB2 Receptors.

 Image result for frontiers in pharmacology

“The mechanism of action of cannabidiol (CBD), the main non-psychotropic component of Cannabis sativa L., is not completely understood. First assumed that the compound was acting via cannabinoid CB2 receptors (CB2Rs) it is now suggested that it interacts with non-cannabinoid G-protein-coupled receptors (GPCRs); however, CBD does not bind with high affinity to the orthosteric site of any GPCR.

To search for alternative explanations, we tested CBD as a potential allosteric ligand of CB2R. Radioligand and non-radioactive homogeneous binding, intracellular cAMP determination and ERK1/2 phosphorylation assays were undertaken in heterologous systems expressing the human version of CB2R.

These results may help to understand CBD mode of action and may serve to revisit its therapeutic possibilities.”

https://www.ncbi.nlm.nih.gov/pubmed/29109685

https://www.frontiersin.org/articles/10.3389/fphar.2017.00744/full

Oral administration of cannabis with lipids leads to high levels of cannabinoids in the intestinal lymphatic system and prominent immunomodulation.

 

 

“Cannabidiol (CBD) and ∆9-tetrahydrocannabinol (THC) have well documented immunomodulatory effects in vitro, but not following oral administration in humans. Here we show that oral co-administration of cannabinoids with lipids can substantially increase their intestinal lymphatic transport in rats. Moreover, immune cells from MS patients were more susceptible to the immunosuppressive effects of cannabinoids than those from healthy volunteers or cancer patients. Therefore, administering cannabinoids with a high-fat meal or in lipid-based formulations has the potential to be a therapeutic approach to improve the treatment of MS, or indeed other autoimmune disorders.”  https://www.ncbi.nlm.nih.gov/pubmed/29109461

“Cannabis sativa has a very long history of medical use. In summary, it has been demonstrated in this work that oral co-administration of cannabis or cannabis-based medicines with lipids results in extremely high levels of lipophilic cannabinoids in the intestinal lymphatic system and prominent immunomodulatory effects. Therefore, administering cannabinoids with a high-fat meal, as cannabis-containing food, or in lipid-based formulations has the potential to be a therapeutic approach to improve the treatment of MS, or indeed other autoimmune disorders.”  https://www.nature.com/articles/s41598-017-15026-z

Translating Endocannabinoid Biology into Clinical Practice: Cannabidiol for Stroke Prevention.

Mary Ann Liebert, Inc. publishers

“Introduction: The endocannabinoid system (ECS) regulates functions throughout human physiology, including neuropsychiatric, cardiovascular, autonomic, metabolic, and inflammatory states. The complex cellular interactions regulated by the ECS suggest a potential for vascular disease and stroke prevention by augmenting central nervous and immune cell endocannabinoid signaling.

Discussion: The endocannabinoid N-arachidonoylethanolamine (anandamide) plays a central role in augmenting these processes in cerebrovascular and neurometabolic disease. Furthermore, cannabidiol (CBD), a nonpsychoactive constituent of Cannabis, is an immediate therapeutic candidate both for potentiating endocannabinoid signaling and for acting at multiple pharmacological targets.

Conclusion: This speculative synthesis explores the current state of knowledge of the ECS and suggests CBD as a therapeutic candidate for stroke prevention by exerting favorable augmentation of the homeostatic effects of the ECS and, in turn, improving the metabolic syndrome, while simultaneously stalling the development of atherosclerosis.”

Chronic Adolescent Δ9-Tetrahydrocannabinol Treatment of Male Mice Leads to Long-Term Cognitive and Behavioral Dysfunction, Which Are Prevented by Concurrent Cannabidiol Treatment.

Mary Ann Liebert, Inc. publishers

“The current study examined the immediate and long-term behavioral consequences of THC, CBD, and their combination in a mouse model of adolescent cannabis use.

All THC-induced behavioral abnormalities were prevented by the coadministration of CBD+THC,

These data suggest that chronic exposure to THC during adolescence leads to some of the behavioral abnormalities common in schizophrenia. Interestingly, CBD appeared to antagonize all THC-induced behavioral abnormalities.

These findings support the hypothesis that adolescent THC use can impart long-term behavioral deficits; however, cotreatment with CBD prevents these deficits.”

https://www.ncbi.nlm.nih.gov/pubmed/29098186

http://online.liebertpub.com/doi/10.1089/can.2017.0034