On October 6, 2015, the Victorian Law Reform Commission presented a report to parliament outlining law reform options to enable treatment with medicinal cannabis in exceptional circumstances. Cannabis, or marijuana, is derived from the Cannabis sativa plant that produces cannabinoids and phytochemicals. Delta-9 tetrahydrocannabinol (THC) is the strongest psychotropically active component of cannabis; while cannabidiol possesses neuroprotective, antiemetic and anti-inflammatory properties. These effects primarily occur due to the interaction of cannabinoids with the endogenous cannabinoid receptors, CB1 and CB2. The CB1 receptor is predominately found in the central nervous system and is responsible for the psychoactive effects of cannabis; the CB2 receptor is in the periphery and contributes to many of the effects noted. It has been proposed that some of the effects of cannabis may also be attributed to activity at other receptor sites, such as serotonergic receptors and vanilloid receptors. The discovery of endogenous cannabinoids and their complex receptor systems has made it apparent that cannabinoids and their numerous physiological actions may be therapeutically beneficial.

Cannabis was first popularised during the 1960s and has become the most widely used illicit drug in Australia. Laws relating to the production, possession, sale and use of cannabis differ throughout the world. Medicinal use is legal in many countries, including Canada, Czech Republic, Israel and parts of the United States. In recent months, specific laws relating to the medicinal use of cannabis in chronic disabling conditions have been challenged, with many countries tabling the topic for consideration.

Stigma remains over cannabis use due to its status as an illicit drug and propensity for abuse. The Diagnostic and Statistical Manual of Mental Disorders, Fifth Edition (DSM-5) now classifies cannabis abuse and dependence under the single term, ‘cannabis use disorder’. This term includes psychotic symptoms of cannabis that occur due to the interaction of THC with cannabinoid receptors in the brain. Genetic studies have shown that marijuana may only cause psychoactive effects in certain people with a genetic modification of their fatty acid amide hydrolase (FAAH) gene. People who carry this mutated gene are more prone to become dependent on the drug as the effects are more pronounced in their body, thus contributing to cannabis use disorder.

With much of society’s focus directed towards the hazards of recreational cannabis use, the potential benefits of medicinal use have in the past been largely overlooked. With an increasing amount of clinical evidence supporting the medicinal use of cannabis, many people are now calling to shift focus to the clinical efficacy, safety and cost-effectiveness of cannabis in the same way as other medications. For any pharmaceutical product to be approved by the Australian Therapeutic Goods Administration (TGA), its therapeutic efficacy and risk-benefit ratio must be favourable. Clinical trials have shown cannabis to have a satisfactory safety profile when used at therapeutic doses. Known short-term side effects include feelings of well-being, drowsiness, loss of inhibitions and coordination, increased appetite, dryness of eyes, mouth and throat, anxiety, and paranoia. Long term effects may include cognitive impairment, associations with psychiatric conditions, and adverse physical effects on the heart and lungs if administered by smoking. There have been no documented cases of death resulting from an overdose of marijuana alone.

As support for medicinal cannabis increases, scheduling changes have been implemented to allow access to those in need. Nabiximols, a product composed of THC and cannabidiol, was included in Schedule 8 of the Poisons Standard in May 2010. In June 2015, cannabidiol was added to Schedule 4 when found in preparations containing less than 2% of other cannabinoids found in cannabis. This distinction is based on the reduced abuse potential for cannabidiol. Cannabidiol is the major non-psychoactive ingredient found in the cannabis plant. Cannabidiol has multiple pharmacological actions, including anxiolytic, antiemetic and anti-inflammatory properties, however, does not lead to intoxication. Nabiximols is currently the only medicinal cannabis product included on the Australian Register of Therapeutic Goods. It is available as an oral spray for buccal absorption, reducing the issue of respiratory effects that may be encountered with the vaporisation and smoking of cannabis.

Nabiximols is currently only registered for the treatment of spasticity in patients with multiple sclerosis who have not achieved satisfactory improvement with other treatments. With the release of further clinical studies, the number of approved indications may increase to potentially include:

  • Severe pain arising from cancer, HIV or AIDS
  • Severe nausea, vomiting or wasting resulting from cancer, HIV, AIDS, or the treatment thereof
  • Severe seizures resulting from epileptic conditions where other treatment options have not proved effective, or have generated side effects that are intolerable for the patient
  • Severe chronic pain where, in the view of two specialist medical practitioners, medicinal cannabis may in all the circumstances provide superior pain management by contrast with other options.

The marketing authorisation for similar indications has already been granted in countries including the United Kingdom, Spain, Canada, New Zealand, Germany, Denmark, Sweden, and Norway. To date, the results have shown promise about improvements in quality of life and reduction of side effects in comparison to other therapies.

Legalising medicinal cannabis introduces the possibility of increased use within the community as a result of greater access. A recent American study showed an increase in the number of cannabis users in states that have legalised medicinal cannabis. The findings were thought to be associated with chronic users able to admit to using cannabis rather than increased availability. Further studies are currently being conducted to determine whether legalisation of medicinal cannabis leads to an increased number of recreational users.

The Victorian Law Reform Commission’s medicinal cannabis report recommends using a similar model to opioid replacement therapy for the dispensing of medicinal cannabis products. Under this proposal, medicinal cannabis would only be dispensed through pharmacies and pharmacy departments electing to participate in the scheme, with patients and carers only able to access cannabis through a pharmacy that has been specifically assigned to them. Furthermore, pharmacists would be required to notify the Secretary of the Department of Health and Human Services regarding the amount and type of products dispensed to individual patients.

With these proposed legislative changes, it is important to understand the position of the general population and the pharmaceutical industry, as well as the future responsibility of pharmacists in the dispensing of medicinal cannabis. With this in mind, the Pharmaceutical Society of Australia (PSA) released a statement in April 2015 regarding medicinal cannabis. The following is an excerpt from this statement:

 

    “PSA notes reports that, in some medical conditions, cannabis has provided positive outcomes to individuals who may not have experienced comparable therapeutic benefits from other clinically proven medicines or treatment protocols… However, PSA does not condone illegal use of cannabis… Further, PSA supports the outcomes of research into the therapeutic use of cannabis to be made widely available so that the evidence base in Australia can be established and enhanced. Where under the treatment of a medical practitioner it is established that the potential therapeutic benefits outweigh the risks, PSA supports the use of medicinal cannabis with appropriate medical oversight and ongoing monitoring of outcomes. PSA does not support the use of cannabis for recreational purposes given the known short- and long-term adverse physiological and psychotropic effects.”

 

Furthermore, the medicinal use of cannabis is supported by 91% of the Australian population.

Last year (2015) has proven to be an important step forward for the many patients who may benefit from the legal use of medicinal cannabis to alleviate some of the physiological symptoms of their chronic condition. The question remains if there will be an increase in the number of conditions added to the ‘exceptional circumstances’ criteria for use, or if these patients will be able to use medicinal cannabis legally for an extended period in the future. For now, these important discussions are transpiring, and for those currently suffering, the results may lead to an improved quality of life.

References:

  1. Baugess JS, DeBolt AA (editors). Encyclopedia of the sixties: a decade of culture and counterculture. Santa Barbara: Greenwood; 2012.
  2. Cerdá M, Wall M, Keyes KM, Galea S, Hasin DS. Adolescent marijuana use from 2002 to 2008: higher in states with medical marijuana laws, cause still unclear. Ann Epidemiol. 2011; 21(9): 714-6.
  3. Cerdá M, Wall M, Keyes KM, Galea S, Hasin D. Medical marijuana laws in 50 states: investigating the relationship between state legalization of medical marijuana and marijuana use, abuse and dependence. Drug Alcohol Depend. 2012; 120(1-3): 22-7.
  4. Freckelton I, Buchanan L, Fatouros H, Gardner B, Hardingham I, Jones D, et al. Medicinal cannabis: report August 2015. Melbourne: Victorian Law Reform Commission; 2015.
  5. Grotenhermen F, Müller-Vahl K. The therapeutic potential of cannabis and cannabinoids. Dtsch Arztebl Int. 2012: 109(29-30):495-501.
  6. Neurobiology of marijuana: cannabis use disorder. In: Galanter M, Kleber HD, Brady KT (editors). The American psychiatric publishing textbook of substance abuse treatment. 5th ed. New York: American Psychiatric Publishing; 2014.
  7. Pharmaceutical Society of Australia. Therapeutic use of cannabis: position statement. April 2015.

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