Many prescribers and dispensers know very little about medicinal cannabis because there has been little research on medicinal cannabis for many years and there is not much information on medicinal cannabis provided in most medicine and pharmacy courses. These documents aim to provide current, accurate and non-biased information to patients and prescribers.

For health professionals, the guidances are designed to provide information about the current state of clinical evidence and raise awareness of how to prescribe medicinal cannabis in Australia under current access schemes.

For consumers, the brochure should raise awareness and understanding of medicinal cannabis, in particular the evidence for how medicinal cannabis products can be used to alleviate symptoms of certain conditions.

There are five guidance documents for health care professionals for each of: multiple sclerosis, epilepsy, chronic pain, palliative care and chemotherapy induced nausea and vomiting, as well as an overview document for prescribers. There is also a consumer-oriented brochure intended for patients and their carers.

Decisions on whether particular cannabis products may be appropriate for a particular patient are still made by the treating prescriber and patient on a case by case basis.

There are a number of clinical trials underway in Australia and globally using medicinal cannabis products and we will update the guidance documents when new evidence emerges. We expect the guidance documents will be updated at least every year, or sooner if emerging evidence emerges.

Guidances are not the same as clinical guidelines. Usually clinical guidelines start with the condition to be treated and the role of medicine-based and non-medicine based options for therapy. Guidelines also usually use studies that provide very high levels of evidence and then undergo detailed review by organisations such as the National Health and Medical Research Council over a period of three or more years. Guidances are documents produced by regulators, like the TGA, to provide advice and further explanations and do not specify requirements that are binding in regulation.

The Australian Government Department of Health and the NSW, Victorian and Queensland state governments commissioned a team from the Universities of New South Wales, Sydney and Queensland, under the co-ordination of the National Drug and Alcohol Research Centre, to review the clinical evidence for the use of medicinal cannabis that had been published in refereed medical journals since 1980. The academics focused on the five areas in which the largest numbers of patient studies have been carried out—palliative care, chemotherapy-induced nausea and vomiting, chronic non-cancer pain, multiple sclerosis and epilepsy in paediatric and adult patients. The guidance documents were endorsed in December 2017 by the Australian Advisory Council for the Medicinal use of Cannabis.

Currently there is only limited evidence about the effectiveness of medicinal cannabis for use in different medical conditions. There is also little known about the most suitable doses of individual cannabis products. There were differences in the numbers and quality of the studies available for review. The academics not only reviewed randomised controlled trials but also patient observational studies, where the studies did not suffer from excessive bias (as assessed by standard international tests for bias in reports on patient studies).

In patients with paediatric-onset drug-resistant epilepsy, cannabidiol products reduced seizure frequency by 50 per cent or more in up to half of the patients and achieved seizure freedom in a small number of patients. This is when cannabidiol products are used as an add-on to current treatments in drug-resistant epilepsy in children and young adults. There are few studies of whether cannabidiol is effective in treating adult epilepsy.

There is some evidence to suggest that medicinal cannabis products may be effective for treating the pain symptoms of MS although this is inconsistent. Studies differ as to whether medicinal cannabis products can help improve bladder function, sleep, quality of life, ataxia/tremor and disability/disease progression. There are currently no studies that compare medicinal cannabis products with commonly-used medications for MS pain and spasticity, so medical cannabis products are more suitable for those who have not responded adequately to other anti-spasticity medication.

There is some evidence that the delta-9 tetrahydrocannabinol (THC) extract of cannabis can reduce pain in both MS-related neuropathic pain and other forms of neuropathic pain, but for many people the reduction in pain may be modest. There is, however, insufficient information to make a conclusion about cannabinoids for the treatment of pain associated with arthritis and fibromyalgia. While some individuals with pain have reported that their use of opioids has been reduced when they also use medicinal cannabis, clinical studies in this area are still ongoing.

High-THC medicinal cannabis products were as effective as many of the prescription medicines they were compared with when most of the studies were carried out (1980s/90s). In recent years, much more effective prescription medicines for nausea and vomiting have become available but there have been very few comparisons of medicinal cannabis products with these medicines. Therefore, medicinal cannabis products should only be prescribed only after newer standard approved treatments have failed.

There was little evidence of benefit to advanced cancer patients with chronic pain. The published studies also showed little effect on appetite, nausea/vomiting, pain, dizziness, mental health or sleep problems. There is no evidence that medicinal cannabis has any anti-cancer activity in human studies or that it can slow the progression of these conditions.

• Access to medicinal cannabis products
• Medicinal cannabis (Office of Drug Control)