WA News Letters Cannabis: What it Means
Cannabis: What it Means
Written by Mr Neil Keen
Tuesday, 29 November 2016

Dear Editor,

Cannabis-based products (CBP) were reclassified as Schedule 8 substances (controlled drugs) on November 1, 2016, following changes to Commonwealth legislation. It is now legal for a specialist medical practitioner to prescribe, and a pharmacist to dispense, CBP in WA.

While there is literature to support the use of CBPs in selected conditions, the evidence is limited and of variable quality. Until now, strict Commonwealth and international prohibition laws surrounding CBPs has limited research in this field. It is hoped that by their reclassification, higher quality research into the efficacy and safety of these products will emerge.

There is moderate-quality evidence to support the use of CBPs in the treatment of chronic pain and spasticity. To date, there is low-quality evidence for their use in sleep disorders, nausea and vomiting due to chemotherapy, and weight gain in HIV infection.

There is also low-quality evidence for the use of cannabidiol (CBD) in seizure disorders. The manufacture of unregistered CBD products is subject to the recent legislative changes, but where containing less than 2% tetrahydrocannabinol (THC) they are classified as Schedule 4 prescription substances, rather than controlled drugs.

Common adverse events in the short term use of CBPs include dizziness, dry mouth, nausea, fatigue, disorientation and hallucination. A recent systematic review and meta-analysis into CBPs for medical use found that there were no studies evaluating the long-term side-effects, even when searches were extended to include lower-levels of evidence.

CBPs remain unregistered therapeutic goods and, as such, the role of Government is to ensure a robust process for the prescribing of medications where therapeutic benefits and long-term side effects are uncertain. To prescribe a CBP, a specialist medical practitioner must obtain approval from the TGA under the Special Access Scheme or the Authorised Prescribers Pathway.

Permission must also be sought from the WA Department of Health, where a CBP Expert Advisory Panel will assess individual requests. In the setting of limited evidence on efficacy and safety, informed patient consent will be essential. A specialist medical practitioner may also wish to apply to appoint a GP as a co-prescriber, however, all treatment decisions surrounding product and treatment dose will remain at the direction of the specialist.

Once approved, a patient will be able to present their script to any pharmacy in WA for dispensing, but supply is still likely to be difficult for many months. To date, there are no Australian products available though it is anticipated that they will become available in 2017.

For now, the prescription of CBPs should proceed with caution, and only when all other treatment options have been exhausted. It is hoped that the changes in Commonwealth legislation will enable medical research to solidify the evidence for the therapeutic profile of CBPs, and that safe, effective and reliable products will become available.

Mr Neil Keen, WA Chief Pharmacist