By Dr Sanjay Nijhawan
As the ACT has recently made steps to legalise medicinal cannabis for personal use, there are once again media stirrings surrounding smoking cannabis and the associated harmful effects of ingesting it this way. Considering the long history of cannabis flowers being smoked in recreational settings, it is important to differentiate this from its medical and clinical applications.
Many international trials regarding medical cannabis have involved smoking or vaporising cannabis. This largely has to do with its history of inhalation as a means of ingestion and due to the fact that inhaling cannabinoids is known to be an effective route of administration, with fast-acting relief. Yet, smoking cannabis has well-known harms, reflective of those associated with smoking tobacco. Combustion of any kind presents damaging substances such as carbon monoxide and burnt particles that can be deleterious to health.
Vaporising cannabis is a slightly safer alternative method that utilises the benefits of ingesting cannabis via the lungs. However comprehensive research of the safety of vaporising in the long term has yet to be elucidated.
It is well-known that inhaling cannabis is the most common method of delivery for recreational users, so does that mean medicinal cannabis in Australia is being prescribed to smoke? By and large, the answer is no.
At Cannabis Access Clinics, the instances where raw flower is prescribed for the purpose of inhalation are rare, except in cases where the patient requires rapid onset. When you consider that only approximately 5% of patients receive treatment through flower form, the uproar regarding smoked cannabis in Australia at the moment is largely unfounded in regards to legal medical applications.
Media storms surrounding the harms of smoking also continue to feed into long-held stigmatisation of cannabis, impeding cultural change and scientific research. However, now that cannabis research is setting roots globally, evolving regulations around the world are allowing for easier conduction of research into a wide range of novel and innovative delivery methods.
Alternative ways cannabis is being prescribed include:
As detailed by FreshLeaf Analytics’ Q3 Patient, Product and Pricing Analysis, oil still dominates the market as the primary delivery mechanism, comprising around two thirds of all product types in the Australian market. As of Q3, there are also now 76 legal products available for doctor prescription here – a jump of more than 40% from 54 confirmed by FreshLeaf in Q1 2019.
Each of these methods above has benefits and drawbacks which can be dependent on the condition treated. In clinical practice, it is important to utilise delivery methods appropriate for the indication. Just as no two cannabis strains are the same, it is important to avoid a “one-size-fits-all” approach to the prescription of cannabis medicines.
Some indications may require multiple methods of ingestion. For example, in regards to arthritic pain, oil dispensed under the tongue and topical applications can be used in combination for greater efficacy.
When ingesting medical cannabis orally, most treatment protocols involve holding the oil or tincture under the tongue for a period of time. This allows for higher bioavailability when cannabinoids are absorbed via the oral mucosa. Although ingesting medicinal cannabis via the digestive system is suitable for a number of conditions, specifically in Crohns, IBS and for children or the elderly, a large amount of the active constituents are degraded in the acidic environment of the stomach or through liver processes. This is called ‘first pass metabolism’, in that edible or capsuled cannabinoids can have less bioavailability and therefore decreased medicinal action in the body.
To avoid ‘first pass metabolism’ other methods can be used to increase efficacy and suit specific conditions. The use of suppositories can be particularly relevant for cancers, elderly patients and in cases of Crohn’s disease that affects the large bowel. In this form, cannabinoids are absorbed more fully, over a longer period of time. For patients who have dysphagia, sublingual wafers, sprays or transdermal patches can be indicated, once again avoiding “first pass metabolism” and directing medications into the bloodstream.
For the future, as research expands, expect to see more novel delivery methods including nanotechnology and cutting-edge extraction techniques that offer a broader range of suitable treatment deliveries for varied demographics and ailments.