More to do before medicinal cannabis rollout

While there has been significant progress towards the mainstream use of medicinal cannabis over the past year, there are a number of missing links that need to be examined before it is rolled out as a therapeutic good, according to the authors of a Perspective published online today by the Medical Journal of Australia.

Professor Jennifer Martin, chair of clinical pharmacology at the University of Newcastle, and Associate Professor Yvonne Bonomo, from St Vincent’s Health in Melbourne, wrote that “several changes to medicines and poisons legislation, as well as significant scientific, pharmaceutical, pharmacological and clinical input are required”.

Most importantly, they believe that more data are required on indications, efficacy, safety and dose range of cannabinoids.

“Although data are available for some already registered cannabinoids, in general, appropriate starting doses and likely toxic doses for other forms of cannabinoids, and in other population groups with different pharmacokinetics are not known,” the authors wrote.

They also noted that central nervous system or other toxicity data, particularly for children, adolescents or “end-of-life” patients who are already taking a range of other medications, need to be collected.

There also needs to be a confirmation that drug constituents are consistent and of high, reproducible quality.

“For instance, there may be batch variation between cultivation sites or over time,” they wrote.

Other concerns included drug stability in different storage conditions, the route of administration and lengths of time the product is prescribed, and the possibility of supplying a potentially misusable substance.

“Clearly, medical practitioners, pharmacists and other health professionals will need training so that inappropriate prescribing and drug diversion are minimised,” the authors wrote.

“If trial data for cannabis finds evidence that supports its use, and if this use can be regulated in a way that enables suitable provision to those who may benefit, then it appropriately becomes another agent in the armamentarium of pharmacotherapy,” they concluded.