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is normalised in the pharmaceutical supply chain.” What is medicinal cannabis? While the cannabis plant contains up to 100 cannabinoids, CBD and THC are typically those being referred to when we speak of medicinal cannabis. CBD and THC both have therapeutic uses and differ based on their psychoactive effects. According to the TGA, “unlike THC, CBD does not cause psychomotor or cognitive impairment, or strong psychoactive effects”.5 THC is the cannabinoid “responsible for the psychoactive effects of cannabis and is the reason cannabis is used recreationally”.6 “Essentially, the difference between medicinal cannabis and illicit cannabis is one of quality assurance and the standardisation of cannabinoids, the former being an important aspect of safety,” said Justin Sinclair, research fellow at NICM Health Research Institute, Western Sydney University. He adds that surveys have shown that many Australians are using illicit cannabis for therapeutic purposes (ie, without medical supervision) for a wide array of different conditions and symptoms. “THC is the main cannabinoid associated with the intoxicating effects of the plant, and while generally found in higher concentrations in illicit supply chains, THC is still present in many of the products being used by medical practitioners in Australia – particularly for chronic pain,” he said. Dr Ben Jansen, Clinical Director of Cannabis Doctors Australia and CDA Health, said: “When you say medicinal cannabis, it’s a broader term because it’s not just CBD by any means. We’re prescribing THC as well. “About 40 per cent of our prescriptions are CBD alone, the other 40 per cent are THC alone and then 20 per cent are blended products. Commonly we’ll prescribe a CBD and a THC so that a patient can adjust the dose of the CBD for their conditions that respond to the CBD, which will be different, in general, from what will respond to the THC.” What conditions does medicinal cannabis manage? Dr Jansen says the medical team at Cannabis Doctors Australia prescribe CBD and/or THC for a variety of medical issues, including “neuropathic pain, inflammatory pain, degenerative pain, and beyond that, the next most common \\\\\\\\\\\\\\\[condition\\\\\\\\\\\\\\\] is anxiety”, which makes up “anywhere from five to 10 per cent of prescriptions”. MEDICINAL CANNABIS 69 for intractable epilepsy, and could represent hope for patients that are resistant to many of the conventional anti-epileptic drugs.” Mr Sclavos added: “PTSD \\\\\\\\\\\\\\\[post- traumatic stress disorder\\\\\\\\\\\\\\\] ... will be a growing area. \\\\\\\\\\\\\\\[There is a\\\\\\\\\\\\\\\] large cohort that uses \\\\\\\\\\\\\\\[medicinal cannabis for PTSD\\\\\\\\\\\\\\\] in Israel.” The safety profile of medicinal cannabis Dr Jansen says that because CBD is not psychoactive, “the rates of side effects are very low”. “The side effects that you get from CBD are usually in the first week and they go away,” he said. “And it’s usually dry mouth or upset stomach – loose bowels, but that usually goes away. “From the THC side of things, the side effects are usually minor, so they don’t cause harm. Somewhere between one per cent and 10 per cent of patients will have a side effect \\\\\\\\\\\\\\\[which will cause them to\\\\\\\\\\\\\\\] then stop taking their medication. That would be sedation, forgetfulness, fatigue ... some patients feel anxious with the THC.” Referring to contraindications for THC use, Dr Jansen says these include schizophrenia, pregnancy and breastfeeding, and severe heart disease. “Contraindications for THC are a past history of schizophrenia or a risk, so, direct family members,” he said. “THC doesn’t cause new schizophrenia ... but it can unmask it in those who were already at risk.” Mr Sinclair says that while most of the studies conducted into CBD “suggest it has a favourable safety profile” with “tolerable side effects and low toxicity”, “knowledge gaps still exist”. He adds that a recent World Health Organization (WHO) report on CBD suggests it doesn’t seem to be associated with abuse potential. “That being said, CBD has a complex pharmacokinetic and pharmacodynamic profile with potential for drug interactions particularly through the Cytochrome P450 system ... As such, investigating the potential for drug interactions is an increasingly important area for researchers, and pharmacists and doctors need to be aware that, particularly at higher doses of CBD, such interactions need to be monitored for,” Mr Sinclair said. TO PAGE 70 Dr Jansen says medicinal cannabis is also prescribed for: • Palliative care. • Restless leg syndrome. • PTSD. • Parkinson’s disease. • Ulcerative colitis. • Migraines. • Tremor. • MS pain or spasms. • Dystonia otherwise undiagnosed. • Blood glucose control (“a couple of patients are on CBD for their diabetes”). • Insomnia. • Chemotherapy-induced nausea. • Autism. • Asperger’s syndrome. • Mood disorder. • Depression. • ADHD. • Schizophrenia. • Epilepsy. • Cystic fibrosis. • Crohn’s disease. • Other conditions. Dr Jansen agrees that a wide range of conditions can be managed with the aid of medicinal cannabis. “The reason why is that you have a system inside your body called the endo-cannabinoid system, which has to do with homeostasis and getting your body back to homeostatic levels of cellular happiness – cellular bliss,” he said, adding that boosting the endo- cannabinoid system “can benefit so many different things”. Mr Sinclair said: “While preliminary research around CBD suggests it may be therapeutically useful in anxiety and certain neurological disorders, the majority of research supporting its use is found for intractable epilepsy. “Due to cannabis research being stifled for the last 80 years due to prohibition, research does have some catching up to do, but it’s fair to say that cannabis research is currently experiencing a significant resurgence of interest. “Several clinical trials reporting efficacy data have shown that CBD can reduce seizure frequency in study participants RETAIL PHARMACY • AUG 2020