Cannabis-based products (part 1): an overview

- October 14, 2019

The legislation around cannabis-based products changed in New Zealand in 2018 to ease prescribing of cannabidiol, and cannabis use may be legalised in the near future. This bulletin aims to provide an update on what products are available and the important differences between them.

The cannabis plant (Cannabis sativa), also known as marijuana, contains hundreds of compounds called cannabinoids. Most are not biologically active. The two most important cannabinoids known to be active are tetrahydrocannabinol (THC) and cannabidiol (CBD).

Definitions 

  • cannabis-based products: the preferred overarching term for any product containing cannabis or a cannabinoid; “medicinal cannabis” is not preferred as it is poorly defined (can be an overarching term or cannabis plant specifically).
  • cannabis plant: any product using the whole plant with all plant constituents e.g. marijuana, cannabis oil
  • cannabinoids: any refined constituent of the plant e.g. THC
  • others: other biologically inactive cannabinoids e.g. hemp. These are distinct to recreational “synthetic cannabis”. 

Cannabis plant

  • Controlled drug – either class B (cannabis oil, hashish) or class C (Cannabis plant, cannabis seed).
  • THC potency varies depending on a number of factors, e.g. plant age, plant genetics, harvesting, processing.
  • Currently illegal to supply. However, patients can legally possess and use cannabis plant for palliative care.
  • Clinical trials using the cannabis plant are hard to interpret due to variability in the quality of products used.
 

Tetrahydrocannabinol (THC) (see bulletin 2)

Cannabidiol (CBD) (see bulletin 3)

Combination THC/CBD (see bulletin 4)

  • The most biologically active cannabinoid, responsible for the “high” from cannabis.
  • Available as refined THC from cannabis, or synthetic THC as dronabinol or nabilone.
  • All products are controlled drugs.
  • No products are approved in NZ.
  • Currently requires MoH approval on a named-patient basis.
  • No products are funded.
  • Biologically active, but less so than THC.
  • Available as refined CBD from companies, e.g. Tilray.
  • Not a controlled drug provided the non-CBD cannabis content is less than 2% . Can be prescribed on a conventional prescription pad for up to 3 months.
  • No products are approved in NZ.
  • No products are funded.
  • Products contain THC and CBD at a defined concentration.
  • May cause a “high” due to THC.
  • All products are controlled drugs as they contain THC.
  • Sativex® is the only approved product in NZ. It is approved for refractory spasms in MS.
  • All other indications require MOH approval on a named-patient basis.
  • No products are funded.

Clinical evidence for cannabis-based products

  • Overall evidence for cannabis-based products is limited.
  • Pharmacologically, CBD and THC are very different – they do not have the same mechanisms of action or clinical effects (beneficial or adverse). See further bulletins for more details.
  • For all indications, including pain, the evidence base for THC and CBD is different. Ensure the correct product is being considered.
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