Medicinal cannabis: Professor Chye extended interview
Professor Richard Chye, Director of the Sacred Heart Hospice and Palliative Care at St Vincent's Hospital Sydney, talks about medicinal cannabis, the dangers of unregulated cannabis products, and where medicinal cannabis is most effective.
A/Professor Richard Chye: I’m Adjunct Professor Richard Chye, Director of the Sacred Heart Hospice and Palliative Care here at St Vincent's Hospital Sydney.
I think there are a few reasons why I'm interested in medicinal cannabis. I think the first thing is there's a lot of patient demand for medicinal cannabis and a lot of these patients are obtaining medicinal cannabis illegally.
And the illegally obtain medicinal cannabis is of unknown potency, is unknown safety and a lot of my patients are very unwell and taking something that I don't know about patient doesn't know about whether it's safe or not is very dangerous. I think for patients.
There's a study for example from the Lambert Institute at University of Sydney where they have unpublished data that shows that the cannabis oil that is labeled CBD only may have lots of THC or nothing at all.
So a lot of patients are spending a lot of money for something that we do not know about. The other thing that other studies elsewhere have shown, for example where the Netherlands allows patients, families anyone to get medicinal cannabis or cannabis for that matter from a dispensary or they call themselves coffee shops that suddenly they found lots of bacteria and fungi in it. And these people are breathing the bacteria and fungi – smoking it maybe – but breathing it in and do we want patients on chemotherapy whose immune system is very low to breathe in bacteria to breathe in fungi?
A lot of multiple sclerosis patients believe medicinal cannabis helps their spasms and yes, there are a few studies that actually show that. But if we don't make sure the cannabis that they're getting legally has no heavy metals in it. And we know heavy metals could be a trigger for multiple sclerosis. Do we want our patients with multiple sclerosis to take something that may trigger off more attacks of multiple sclerosis?
Finally, even in smoked cannabis from the United States, they have found that their are pesticides in the smoke that have gone through a water filter similar to those Turkish smoking implements – and found that in the smoke they had pesticides.
Do we want our patients to inhale pesticides, to consume pesticides, which the manufacturers, the legal manufacturers have not been able to take out or even tested for it?
So it's all about safety for patients, about making sure that I know what they're taking and what they're not taking more importantly, and that they're not going to cause themselves harm.
Medicinal cannabis has helped a lot of patients as well. And we're not sure what is helping the patients and we're still learning about medicinal cannabis and what it can do. I'm still learning, even though I've prescribed it for more than 60 patients. Yes it can help improve appetite in some of my patients; not all my patients. It can help with nausea in some of my patients, but not all. It can help patients with nerve pain, but not arthritis and bone pain.
That's what I'm learning. And if patients have tried every other medication to help the nausea, to help their appetite, to help their nerve pain and it is not working then I'm comfortable with trying medicinal cannabis to see that makes a difference for these patients.
But I do it in a very controlled way, making sure that patients are taking the medicinal cannabis that has been deemed to be free of bacteria, to be free of heavy metals, to be free of pesticides. Then I know that the medicinal cannabis that they’re taking is relatively safe. And I carefully monitor. I carefully monitor for the efficacy to make sure it works. I monitor for side effects and make sure that medication has not made people too sleepy, for example. I also make sure that if it doesn't work, then I say to the patient, “We've given it a good go”. And then we stop.
A lot of my palliative care colleagues are sceptical about what I do because they rightly say there's very little evidence for what I do, but in palliative care I can also argue that a lot of what we do in palliative care there’s actually very little evidence as well.
But the experience of using medicines in palliative care – in carefully starting at a low dose and carefully monitoring for side effects – applies to medicinal cannabis as well.
So yes, I think a lot of our patients are already on cannabis whether we like it or not, whether we think they are on it or not. And I would prefer those patients to be on medications that we know about, that we know are relatively safe and I want to be able to monitor patients carefully for any side effects from the medicinal cannabis. I want to know that they are actually getting effect from it, but I also want to counsel those patients that if it's not working, don't bother using it any more – saves them money.
So for those two main reasons I move from being a very sceptical doctor about medicinal cannabis to someone now willing to help patients to use medicinal cannabis. I explain to my patients, medicinal cannabis is not the panacea for everything. Everybody thinks that medicinal cannabis would treat everything. And I'm very clear that it does not. As I said to you, it helps nerve pain and if someone comes to me with arthritic pain, I will say no, it's not going to work. I'm very careful about what I use and trying to use the evidence as much as possible to make the right decisions for those patients.
Medicinal cannabis and epilepsy
The use of medicinal cannabis for symptoms is very tricky because there's very little guidance as to what I should use. We talk about, for example, the use of CBD only to treat epilepsy that's very hard to treat, or what we call intractable epilepsy. Most of the studies now show that yes medicinal cannabis can be useful, especially the CBD only, but expect it to be useful like any other anti-seizure medication, meaning that it works for some, but it's not going to work for others.
Yes, the media portrays that the CBD and the Epidiolex works for seizures in children who have not been able to be treated. What the media doesn't tell you, in fact, a lot of children have tried CBD or Epidiolex and it hasn't worked, so it gives the public a false sense of security that CBD is going to work for everyone. And in fact it doesn’t.
In fact there's now suggestion that because of the illegal cannabis now being known to contain sub THC that perhaps a little bit of THC in patients with refractory epilepsy may not be a bad thing.
So you can see, even in a child with refractory epilepsy, we're not completely sure is CBD alone the right drug, or should there be a little bit of THC? So this is going to be a moving feast as the doctors get to know what medicinal cannabis does and does not do anymore.
Yes, for refractory epilepsy CBD seems to be the main drug, but we may need a little bit of THC, and there's no guidance to help me understand how much CBD, how much THC. So in terms of using medicinal cannabis, it is about trial and error – it’s trying to monitor carefully for the efficacy of medicinal cannabis, it’s trying to monitor carefully for the side effects.
I know that lots of patients require lots of CBD to control epilepsy. I do have a patient with refractory epilepsy, who's on a fraction of that dose and for her it has changed her quality of life. For her it’s given the fact of an ability to reduce one of her seizure medications and that has created better clarity of thought for her.
So even though it has reduced her epilepsy, her seizures – not completely – there are other benefits in terms of, for her, providing clarity of thought. So when I monitor for the efficacy of medicinal cannabis, it is not just the number of seizures for this lady. Or, it's not just the pain or it's not just the nausea, it is also what that medicinal cannabis has done for the patient overall. It’s not just the one target symptom. It's about quality of life for that patient.
Chemotherapy-induced nausea and vomiting
In other circumstances, for example, in chemotherapy-induced nausea or vomiting, most of the studies suggest that it's a THC-only medication that we should be trying. But I can tell you there are studies that are using a combination of THC and CBD in a one to one ratio.
So, again, is THC the only drug for chemotherapy-induced nausea and vomiting, or is there a combination? And the answer is we do not know at the moment. And therefore, yes, I will try the combination and monitor very carefully again.
Medicinal cannabis for pain
Again, most of the studies have shown in pain, especially neuropathic pain, that most studies use a combination of THC and CBD, in a one to one ratio, but I do know other prescribers in Australia who are using a THC to CBD 1 to 20 ratio and finding some effect from it as well. In other words, there is actually very little guidance about what is the right dose, what is the right combination and what I've been doing is start low, build up very slowly and look for those side effects and look for those benefits and look for benefits in many, many different domains.
I'm also doing a study here at St Vincent's Hospital where we are vaporising cannabis, specifically vaporising dried cannabis flower that is imported from the Netherlands, which I know is of a specific potency and safety and then I’m having patients inhale cannabis via a vaporiser. I do not promote smoking cannabis because smoking cannabis burns cannabis at 450 degrees and creates ash, which patients then inhale. So I do not promote smoking of cannabis.
What I do is I vaporise the dried cannabis flower to 200 degrees. And patients breathe in the vapor. So there's no ash and that's the safety component of that study. What I also do then is change the dose of the cannabis each day and do blood tests to try and correlate the levels of THC in the blood with how well a patient's appetite is.
So in this study. I'm also taking lots of blood samples and measuring THC levels in their blood to see whether it correlates with appetite. The study is about one third recruited so we're still looking for more patients and the main criteria for this study is patients with cancer, who have lost appetite, not necessarily lost weight, and want to improve their appetite.
So for those patients that I've looked for, again it has worked on some patients and has made no difference in others. Again it points to us that medicinal cannabis is not the panacea for everything.
Side effects of medicinal cannabis
There's always concern about THC causing hallucinations, causing intoxication. And that's why we have to monitor patients very, very carefully and starting doses at a low level and building up slowly, then you actually can find when patients start to get that intoxicated effect. And if they reach a level where they start to feel too intoxicated or too drowsy, then I pull the dose back a little bit, so you can see what careful monitoring requires and what I need to look for in patients on medicinal cannabis. If they start to get too intoxicated or they find that the cannabis is making their thinking very disordered then I also know to pull back.
What I also talk to my patients before starting cannabis is to tell them what are the possible side effects. The main side effects is going to be tiredness and sleepiness and that's why I give most of the cannabis, especially the THC component, in the evenings.
I also talk about the possibility of hallucinations – psychosis, because we know THC can do that but I also explain by starting low, the chances of that happening at a low dose is very very low. We know of an association of cannabis and schizophrenia and most of the association is young teenagers or young adults who smoked a lot of cannabis. What we don't know is that the cannabis causes schizophrenia or were these patients, these young adults, going to develop schizophrenia anyway, but were also attracted to marijuana.
So, you can see whilst there’s an association – it's not a causative link, but I still have to tell my patients that there is that causative link and hopefully at the age of these patients that their mind, my brain is already fully developed and wise enough so that we don't develop schizophrenia.
We all know that cannabis can cause dependency, can cause addiction. And I do warn my patients those are possible side effects. Even though the possibility of that is low because I'm starting at low doses. So part of the process to get authorisation from the TGA, and from the state health departments, is that I have carefully documented my explanation, and my education, of those side effects to the patients and documented by getting them to sign a consent form that they have an opportunity to ask questions. That they understand what they are getting themselves into. And yes that is part of the process of getting permission from the health authorities to prescribe cannabis.
What is the patient journey?
Most patients have already heard about medicinal cannabis and how it can help their symptoms be it pain, be it nausea, be it appetite, and are very keen on using medicinal cannabis or at least trying it.
And the first thing to do is to ask the doctors about it. I do recognize that a lot of doctors don't know much about medicinal cannabis and for them this is a very, very new area. Perhaps they may be able to find doctors or the GPs or the doctors can find other doctors like myself who are willing to carefully monitor the use of medicinal cannabis, so like any referral to a doctor or specialist their GP needs to write a letter referral, document exactly what the illness is now what the symptoms are what they've tried to improve their symptoms. Medicinal cannabis doesn't have a lot of evidence behind its use, behind its efficacy, but the Government and myself recognize that we should be trying medicines that have been shown to be effective.
And if those medicines don’t work for the appetite, if those medicines don't work for the nausea or don't work for the pain, then they have to be carefully documented that it doesn't work and medicinal cannabis is used as a drug of last resort.
And if patients see that they've tried lots of different things and want to try medicinal cannabis, then I think it's a reasonable thing for their doctors to refer to doctors who have some experience in medicinal cannabis.
How long should a patient be on medicinal cannabis until you know it’s been effective or not?
The way I assess whether medicinal cannabis has worked usually takes about three months. The reason for that is, I have to document the symptoms and the severity of symptoms before they start cannabis and then I have to start cannabis at a very low dose and build up slowly. Why I start low and build up is that I don't want to scare patients.
If I start at a very high dose and caused lots of side effects then patients will suddenly say I don't want it anymore. In fact, I did have one patient who I had spent some five months getting medicinal cannabis – my very first patient – who got side effects from it and then said I don't want any more.
So, from my point of view, there was a very good learning experience, whereby I have to start patients at a low dose and build up slowly.
I don't want to scare my patients because they put a lot of effort in to come to see me for medicinal cannabis and obviously I have to put the effort in to obtain the permission to prescribe medicinal cannabis. So one dose to undo all of that is not a good experience.
So I need to start the doses very low and build up slowly and you can expect that building up to an appropriate dose would therefore take some time and could take as much as 2, 3, 4 weeks to get to the dose where, I think, to get to a dose where the patient, I think has received an adequate trial and then to monitor to see whether it is also making any difference to those symptoms. Has the improvement in symptoms actually occurred? If there's no improvement in symptoms when they get to the highest dose at about two or three months, then I'll say to patients you've given it a good go. You've tried medicinal cannabis and I think we shouldn't be continuing anymore.
If patients have a partial response, then I may say to the patient we could push the dose a little bit higher and see how high we can go but also balancing that on how much side effects that the cannabis can also be providing.
Ultimately the dose of cannabis depends on how comfortable the patient is with the improvement in symptoms. If the appetite is improved on a very low dose of medicinal cannabis, that's fantastic. We've achieved the outcome we want. We've achieved improvement of appetite without having to go to a higher dose. And that’s what I’ve seen. I've seen patients with difficulties and appetite will have different doses for different patients, there's no one right dose for patients – every patient is very different and that’s why I start low and go up to where the patient can tolerate and also get the maximum effect from the medicinal cannabis.
So, by and large, it's about two or three months that I will have an idea whether the medicinal cannabis is not making any difference, but I also say to my patients right at the outset as part of my consent process that medicinal cannabis may not work.
And I will say we’ll stop when I think it doesn’t work, and that’s the contract I have with patients that start medicinal cannabis.
What is the cost of medicinal cannabis?
The cost of cannabis has changed over the last 18 months. The first bottle of medicinal cannabis I got cost somewhere between $600 and $800 18 months ago, for a bottle consisting of 25 ml. That bottle of 25 ml now costs less than $100. I think that there are so many companies in Australia now offering medicinal cannabis that the competition has reduced the price dramatically.
I think the price will come down further, especially when Australia starts to produce its own pharmaceutical grade medicinal cannabis. That hasn't happened yet. I think it will probably occur at the beginning of 2019 or the middle of 2019, but we're not there yet. But once the Australian product comes onto the market, I think the price of medicinal cannabis will come down dramatically.
How long will a bottle last?
Medicinal cannabis comes in different strengths and comes in different volumes as well. So, some of them will come as 25 ml, some as 40 ml, some as 100 ml. How long a bottle will last will depend very much on the dose that the patient is on.
It is interesting that if you are doing science HSC, we recognise that 20 drops of water equals 1 ml. In fact, because medicinal cannabis comes in oil it comes as 30 drops in 1 ml. l I have patients who will respond on 6 drops a day – no more than that. So 25 ml will last a patient 3, 4 or 5 months.
I have other patients who are given 40 ml bottles and they take 2 ml every day so that bottle lasts 3 weeks. So yes, an individual bottle will last for a long time or a short time, and will depend on the dose that the patient is taking.
Is medicinal cannabis imported? And is it natural or synthetic?
So, all the cannabis that’s available in Australia is imported. We are waiting for Australian product that’s currently being grown, but not yet been successfully processed into a pharmaceutical grade medicinal cannabis just yet, but I hope that will come in early 2019.
There are two main types of medicinal cannabis. Yes there is naturally grown THC and CBD, which is extracted from the cannabis plant itself and in fact there are three different cannabis plants and a lot of the processing plants in overseas countries will grow the cannabis and extract the THC and CBD from those plants.
There are a few synthetic THC products, mainly, but they are not widely in use in Australia and actually are a bit more expensive than the naturally grown naturally extracted medicinal cannabis.
Even from the point of view of cannabis THC and CBD extracted from the cannabis plant, the oils at the moment can be somewhere between $100 and $300 per bottle, depending on the volume and then there are other cannabis extracts that are dissolved in alcohol and come as a spray that can be sprayed into the mouth and unfortunately those cost about $1,000 a month. So doctors have to also consider for their patients, what their patients can afford and what is available and most useful for their patients. We need to explore and make sure that it’s easy for patients to afford, but also be able to take it effectively.
Do you think there is a future for medicinal cannabis?
I think the future for medicinal cannabis will continue to grow. Like many medications medicinal cannabis will have a fad, and there will be a demand for medicinal cannabis as patients feel that it will make a difference for them as doctors become much more confident with medicinal cannabis.
I also think that when we learn more about medicinal cannabis and then finally realise that it is like any other drug, meaning that he works for some and don't work for others. Then we may see a slight reduction in demand because suddenly we have a drug that may not always work.
So I think in the future coming up. Yes, there will be a demand, but in the distant future I think there will be probably wiser use of medicinal cannabis or more appropriate use.
Will medicinal cannabis be subsidised by the Government?
And at the moment I think not. Australian government wants to subsidise medications that have proven to be useful; that have been proven to replace other medications; that have been proven to be cheaper than other medications; have been proven to be safe. Ultimately, have been proven to make a difference to the health system. To create the proof that medicinal cannabis is useful in all of those senses we need research.
Unfortunately, the research is only being funded by governments, not by the people who make medicinal cannabis. We need the research to be able to prove to government that it’s useful and that is for any drug that we put up to the Government, whether it's an antibiotic or epilepsy drug or new chemotherapy drug.
The pharmaceutical companies have a lot of research to make sure that it works and prove that it makes a difference to the health system before the government will subsidise it. I fear that we will not get the same level of research with medicinal cannabis.
If you think about it, as I said, there are 17 companies who are wanting to distribute their medicinal cannabis product. It is not only the company who has put up the money for the research, it is every other company as well. So every company is hoping someone else will do the research and therefore, nothing is being done. At the moment governments are the only ones who are really putting up money in Australia to do the research, which is not going to be enough.
Research is also occurring funded by Government, as I said, to help us understand how medicinal cannabis works in pain, in appetite, in chemotherapy-induced nausea, vomiting, and also in epilepsy and I hope there will be more.
There's also research going on in universities in Australia to look at whether cannabis impairs patients’ driving. Does it impair driving? We don't know.
Currently, the Law says if we are able to detect cannabis in someone who is driving then they are driving under the influence, whether the cannabis is low level or higher level. So the law has not caught up with what's happening now, especially when we are moving away from breathalyser testing to saliva testing, where they can be very sensitive and pick up medications like cannabis, but also opioids.
Can you drive whilst using medicinal cannabis and does the law make exceptions for this?
The law in Australia regarding driving has not caught up with patients on medicinal cannabis. Currently, I understand the law says that if you have a trace of cannabis In your blood, whilst you're driving, then you are driving under the influence of cannabis, even if you've had taken that cannabis three weeks ago.
Cannabis stays in the body for up to three weeks, so yes if someone's taken the legal cannabis and are caught driving three weeks later, they are still deemed driving under the influence. So the law has not caught up with medicinal cannabis and driving.
For my patients on medicinal cannabis they are driving under the influence under that legal definition, even though it's given for medicinal and authorised purposes.
So this is a problem for my patients on medicinal cannabis about whether they can drive. I would advise and product information advises: do not drive and do not operate machinery.
And that's the same thing with patients on opioids for the cancer pain; that's the same thing for someone who has taken a sleeping tablet the night before. The law has not caught up.
There is research going on in some Australian universities to test what level of cannabis in the blood starts to affect driving capability. And until we have that research and thankfully, it's supported by governments in Australia, until we have those findings, those research, the law cannot change at the moment.
How do we also differentiate medicinal cannabis from illegally obtained cannabis? Again those tests do not differentiate the two, so the Law has not caught up as well. Our State police jurisdictions know this is a problem. Our Federal Police know this is a problem, but they do not have any answers just yet.
For my patients who are prescribed medicinal cannabis, I advise do not drive. I will offer them a letter that they as a patient of mine are obtaining medicinal cannabis that is authorised, not only by the Federal Government, but also by the state jurisdictions – in this case, New South Wales. The law has not been tested yet and none of my patients have been caught. But I guess that's going to be a matter of time.
The other issue is patients who want to go on holidays with their medicinal cannabis. I did have a patient who has got cancer, who wants to spend holidays with their family, a young family, as much as possible and I would certainly promote and encourage that.
But she went on holiday to a different state, which means that she was bringing her cannabis from New South Wales to a different state. Our laws again have not caught up, in terms of whether patients can bring medicinal cannabis across borders.
I also encourage patients to go overseas to visit family. Which may be their very last time from a palliative care point of view and I would not deny them that opportunity.
And again, they have to take their medicinal cannabis across international borders and again there's no agreements between governments, for example, about how to deal with authorised cannabis.
There was a child who had obtained their cannabis from Canada and had brought their medicinal cannabis for her seizures back to the UK, where she lived. And that cannabis was confiscated by customs because the mother wanted to declare it properly. And because the cannabis was confiscated, that child ended up in hospital with uncontrolled seizures.
That created issues for government and I'm sure will create issues for all governments across the world, in terms of are we going to be compassionate or not looking after the people that live in our countries.
Laws are being created, are being thought about, are being shared between countries at the moment but we're not there yet.
And again, I offer advice to my patients that yes, I will provide them with letters and copies of the authorisations that I have received and I hope that they're not going to be the first test cases in those respective countries that they've gone to visit.
I think we need to be compassionate for our patients, whether it's within our own borders or whether patients go overseas.
We need to be able to show compassion to all our patients.
Last Reviewed: 28/10/2018