The Australian Federal Government legalised access to medicinal cannabis in 2016.

More than 100 different cannabis products are now available to prescribe. Most are oral preparations (oils) or capsules containing delta-9-tetrahydrocannabinol or cannabidiol. Dried-flower products are also available.

As most products are unregistered drugs, prescribing requires approval under the Therapeutic Goods Administration Special Access Scheme-B or Authorised Prescriber Scheme.

Special Access Scheme Category B applications can be made online, with approval usually being given within 24–48 hours. However, supply chain problems may delay dispensing by the pharmacy.

By the end of 2019, over 28,000 prescribing approvals had been issued to patients, involving more than 1400 doctors, mostly GPs. More than 70,000 approvals are projected by the end of 2020.

Most prescriptions are for chronic non-cancer pain, anxiety, cancer-related symptoms, epilepsy and other neurological disorders. However, the evidence supporting some indications is limited.

Many doctors are cautious about prescribing cannabis. While serious adverse events are rare, there are legitimate concerns around driving, cognitive impairment and drug dependence with products containing delta-9-tetrahydrocannabinol. Cannabidiol-only products pose fewer risks.

Introduction

Legal access to medicinal cannabis products is now increasing. Many countries are relaxing their restrictions on cannabis in the face of escalating community interest, commercialisation of products and strong patient demand for access. The vast majority of Australians support access to medicinal cannabis.1 This support is galvanised by media stories of patients with intractable conditions whose lives have been transformed by cannabis-based medicines.2

The medical profession is understandably cautious around medicinal cannabis. A survey of Australian GPs reported that they felt uneducated around access pathways, available products and the evidence base supporting medicinal cannabis.3 Patient enquiries are common, yet only a small proportion of doctors feel comfortable discussing cannabis with their patients. Overall, GPs are positive about medicinal cannabis prescribing, given sufficient education, particularly for serious conditions such as cancer pain, chemotherapy-induced nausea and vomiting, epilepsy and difficult-to-treat neurological conditions.3 Specialist colleges and the Australian Medical Association remain conservative voices in the medicinal cannabis debate with concerns around the limited evidence from clinical trials and possible adverse effects.4,5

What is medicinal cannabis?

The cannabis plant contains hundreds of bioactive molecules, most of which are as yet uncharacterised. The two best studied cannabinoids are delta-9-tetrahydrocannabinol (THC) and cannabidiol (CBD).

THC is responsible for the intoxicating effects of cannabis due to its action on CB1 cannabinoid receptors.6 Despite intoxicating effects at higher doses, clinical trial evidence generally supports the efficacy of THC in treating conditions such as chronic pain, spasticity in multiple sclerosis, anorexia and cachexia, Tourette syndrome and chemotherapy-induced nausea and vomiting.7,8 Trials currently underway will help to better define the role of THC as a therapeutic across these and other conditions.9,10

CBD has a very wide range of pharmacological actions but no intoxicating effects. Early evidence suggests therapeutic actions of CBD at relatively high doses (300–1500 mg) in treating epilepsy, anxiety and psychosis.11-13 Numerous clinical trials are underway for other conditions such as neuropathic pain, drug and alcohol dependence and neurodegenerative disorders. In many countries, CBD is readily available in over-the-counter nutraceutical ‘wellness’ products. These contain very low doses (e.g. 5–25 mg) for which there is little current evidence of health benefits. Over-the-counter access to CBD is not yet available in Australia, although the Therapeutic Goods Administration (TGA) is currently examining the possibility of such simplified access.14,15

Useful Australian websites on medicinal cannabis are listed in the Box.

Box - Useful websites for information on medicinal cannabis in Australia

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