Broadly speaking, medicinal cannabis is cannabis prescribed to relieve the symptoms of a medical condition, such as epilepsy. It is important to make the distinction between medicinal cannabis and recreational cannabis. Recreational cannabis is the form of cannabis that people use to get ‘high’.1
For some people suffering from chronic or terminal illnesses, conventional medicines do not work, or do not work as effectively as medicinal cannabis. Also, for some patients, conventional medicines may work but cause debilitating side effects that cannabis can help to relieve.2
What are cannabinoids?
The main psychoactive ingredient of cannabis is tetrahydrocannabinol (THC), which acts on specific receptors in the brain known as cannabinoid or CB1 receptors.3
Research has found that the cannabis plant produces between 80 and 100 cannabinoids and about 300 non-cannabinoid chemicals. The two main cannabinoids that have been found to have therapeutic benefits are delta-9-tetrahydrocannabinol (THC) and cannabidiol (CBD). There have been claims that a number of other cannabinoids have therapeutic properties, but these have not yet been proven.1
The main difference between the two cannabinoids is that THC has strong psychoactive effects, meaning it makes a person ‘high’, whereas CBD is thought to have an anti-psychoactive effect that controls or moderates the ‘high’ caused by the THC. CBD is also thought to reduce some of the other negative effects that people can experience from THC, such as anxiety.4
The psychoactive effects of THC, such as euphoria and feeling relaxed or sleepy, are well known, but THC has also been found to have analgesic, anti-inflammatory and antioxidant properties, as well as being able to prevent and reduce vomiting.1
Research is being conducted into CBD for its potential to treat epilepsy, schizophrenia and other psychotic disorders, type 2 diabetes, inflammatory bowel disease, some tumours, and drug dependency.1
The endocannabinoid system
The endocannabinoid system is a unique communications system found in the brain and body that affects many important functions.5 It is made up of natural molecules known as cannabinoids, and the pathways they interact with. Together, these parts work to regulate a number of activities, including mood, memory, sleep and appetite. It is thought that medicinal cannabis can treat various illness by acting on the endocannabinoid system.6
Types and forms of medicinal cannabis
There are three main forms of cannabis that can be used medicinally:
- Pharmaceutical cannabis products that are approved by an organisation such as the Therapeutic Goods Administration (TGA), including nabiximols (Sativex®) and synthetic cannabinoids such as Dronabinol®. Sativex, which comes as a nasal or oral spray, has been approved in over 24 countries for treating spasticity due to multiple sclerosis.
- Controlled and standardised herbal cannabis (plant products), such as the products produced in the Netherlands.
- Unregulated and illegal herbal cannabis (plant products), which contains unknown concentrations of cannabinoids and potentially harmful impurities such as bacteria and mould (USA only).7
Why smoking cannabis for medical purposes is not recommended
A number of people make the claim that smoked cannabis should be considered as a treatment for various medical conditions or even as a cure for cancer. However, there are two major concerns regarding this type of cannabis and this method of administration. Firstly, smoking is a particularly harmful way of taking cannabis, mainly because carcinogenic substances are inhaled directly into the lungs. Smoking cannabis is not recommended by health authorities, as the smoked form contains at least 50 of the same carcinogens as tobacco.8
Secondly, the majority of medicines used in Australia are produced under strict conditions: that way, doctors who are prescribing them (as well as people who are using them) know exactly what is in them. It is important that doctors know that medicines have been tested and that each dose is the same. This means doctors can monitor the effects of the drug and doses can be adjusted according to a patient’s needs. When recreational cannabis is used as medicine, doctors and patients can’t be sure of these things – they don’t know how strong it is or what mix of chemicals is in it, and as a consequence, one dose will never be the same as another.8
There is a considerable need for medicines and therapies that can help and alleviate the painful symptoms of a number of illnesses and diseases. An increasing number of studies suggest that medicinal cannabis in the form of oral extracts, sprays or pills can reduce these symptoms and aid in the treatment of some illnesses. However, as with many other drugs, medicinal cannabis can also cause unwanted side effects, such as difficulty with concentration, dizziness, drowsiness, loss of balance, and problems with thinking and memory.9
Special Access Scheme
Under the TGA Special Access Scheme, some forms of medicinal cannabis are currently available. The scheme provides for the import and supply of an unapproved therapeutic good to individual patients on a case-by-case basis. Recently, the TGA has made changes to its Special Access Scheme that will make it easier for medical practitioners to prescribe cannabis-based medicines for patients in need, under certain conditions.