Nearly 18 months after new regulations allowed doctors to begin prescribing cannabis-based medicines to their patients, many challenges remain. By Russell Brown.
Earlier this year, the International Association for the Study of Pain published a review of the evidence for cannabis as a treatment. It concluded that although "basic science advances are promising", high-quality clinical evidence is still scant. "More research is required to elucidate the benefits and harms of therapeutic use of cannabis and cannabinoids for the treatment of pain."
That's why Pharmac doesn't subsidise cannabis medicines and Medsafe has not approved any since 2010. But there's another way of looking at it, highlighted in two surveys of thousands of medicinal-cannabis users (almost all of whom were doing so illegally) under the auspices of Otago and Massey universities respectively. Many of those patients reported something striking: that cannabis allowed them to substantially reduce or end their use of onerous prescription medication and their quality of life improved as a result.
In the Massey survey, published last year, the class of prescription medication most often stopped as a result of cannabis use was gabapentinoids: pregabalin and gabapentin. The class in which use was most often reduced was opioids, with 95 per cent of those using them reporting a reduction as a consequence of using cannabis. In the Otago survey, 30% of patients stopped their opioids entirely.
A large Canadian study published this year found similar results: medicinal-cannabis treatment had little effect on low-level chronic users of opioid painkillers, but consumption by the heaviest users fell dramatically. Another study, published in May in the Canadian Journal of Anesthesia, followed hundreds of chronic-pain patients after enrolment at cannabis clinics: the number using opioids halved and general health scores, including anxiety and depression, improved.
All of these are observational studies; they rely on patients' self-reporting and are not a substitute for the randomised controlled trials we use to test the safety and efficacy of individual products. They don't, in themselves, prove that cannabis treats pain or any other condition effectively. So, what do they mean?
"If you're giving up these really powerful medications, then clearly something's working," says Dr Geoff Noller, who directed the Otago survey alongside the advocacy group Medical Cannabis Awareness NZ. "The two areas where people were primarily using cannabis for therapeutic purposes were chronic pain and anxiety. The thing about chronic pain is that it's heavily associated with depression and anxiety – we shouldn't be surprised by that.
"If you have a medication that has a mildly analgesic effect, but relaxes you and lets you get a decent night's sleep, what a remarkable thing that would be. And I think this is what a lot of these people are responding to. And then they don't need these other medications, especially if those other medications have significant side effects."
About 10 per cent of patients surveyed were women suffering endometriosis and the results there were strong enough – more than 95 per cent reported improvements in pain relief and sleep and 60 per cent had stopped a medication, usually an analgesic – that Noller published a paper on it. One of his co-authors, Australian women's health researcher Dr Mike Armour, has launched a clinical trial to investigate further.
But there are human stories behind the survey data and they fall into a pattern. Auckland medical-cannabis advocate Pearl Schomburg has told of the moment she glimpsed her reflection in a chemist's window, holding two full shopping bags of prescribed medicines for her multiple auto-immune conditions, and broke down in tears. She could not, she decided, live like this.
Rucksack full of pills
For New Plymouth man Gareth Duff, it was not shopping bags, but a rucksack full of pills. Duff's spiral down from a "perfect" life with a good job, a young family and a new house began in 2013 with food poisoning that damaged his kidneys and sent him into violent, incessant seizures that fractured his spine. His next few years were a story of misdiagnosis, constant pain and endless prescription medications. Once, he was so loaded up with his prescribed dose of oxycodone that he wrote off a company vehicle. After a move to Australia, he even briefly used street heroin.
"The medication had broken me," Duff recalls. "I'd self-harmed multiple times, tried to overdose. People who haven't taken those medications have no idea. It makes you do things, lose control. The whole world just shuts down around you and the next thing you know, you're hurting yourself."
What Duff didn't know then was that in 2014, a line in his patient notes had flagged him as a drug-seeker. That didn't prevent him being prescribed powerfully addictive drugs for years afterwards. But one doctor in his orbit was determined that it would prevent him having access to medical cannabis after he asked about it. He says the same doctor even contacted his hip and back specialist, who cancelled all his referrals.
Ironically, it was an addiction psychiatrist who came to Duff's rescue. Dr Ryan Bell, a Canadian working with the Taranaki District Health Board's alcohol and drug service, prescribed him a cannabidiol (CBD) product. This action had become easier after a regulatory order from then-Associate Health Minister Peter Dunne in the final days of the last National Government.
Duff became a literal case study in opioid withdrawal, getting off oxycodone in only six months. These days, he manages his pain with Tilray 25, the only THC product so far available under the new medicinal-cannabis regime, but happily admits to also topping up with "green fairy" products chosen in consultation with a medical herbalist. He's a boisterous presence who now advises others trying to navigate the system and corresponds regularly with Ministry of Health officials.
"I'm someone the patients can talk to who has been to those horrible places. I'll be the open book."
New Zealanders using cannabis for therapeutic purposes within the system are still vastly outnumbered – by 10-15 times – by those outside it. They include Bailey (not his real name), who in 2013 suffered a severe electric shock while working as an electrician. Doctors later discovered his injuries had cut off blood supply to his hip and he underwent a hip replacement. Then his abductor muscle snapped off, twice. He suffered intense pain and progressed from daily morphine to oxycodone. He hated the oxycodone, but it took five difficult years to wean himself off it: "It sounds silly, but it hurt to look through your eyeballs."
He was prescribed gabapentin late last year, to which he had a violent adverse reaction – he vomited for a week. When a GP prescribed him pregabalin this year, he asked if it was similar to gabapentin. He says he was told it was "a completely different drug" and would have no significant side effects. In fact, pregabalin and gabapentin are very similar drugs and the Medsafe data sheets for both list a range of potential side effects. They include an increased risk of suicidal ideation.
Bailey confesses that in the three weeks he took pregabalin, he decided to ask his doctor about voluntary euthanasia: "I thought, 'I'm not living like this. If this is the rest of my life, I don't want it.' I had a lot of dark thoughts."
The final straw for Bailey came when he was on a public library computer trying to change his KiwiSaver account and couldn't remember both the mobile phone number he'd had for 15 years and his daughters' middle names. After a neighbour printed out the Medsafe information for him, he stopped his pregabalin.
About the same time he was prescribed pregabalin, Bailey was given a homemade cannabis balm, which could be used both topically and orally. It seemed to help. But the doctor who assured him pregabalin would have no side effects had a very different view of cannabis.
"When they put me on pregabalin, I told them I was trying the balm and they went nuts and put notes on my file. I asked what they thought, and then I could see the doctor typing into her computer that I was on marijuana. It was like it was a drug-dependency thing. She was really anti."
Having spent years weaning himself off prescribed opioids, he had been marked as a drug-seeker.
Pregabalin and gabapentin were once subject to the same special-authority provisions that prospective cannabis patients and their doctors have had to navigate in recent years. Prescriptions have rocketed since Medsafe waived the restriction in 2018. Medsafe published an update for prescribers this year reminding doctors to monitor patients for cognitive problems and flagging gabapentin's abuse potential. (The most recent report from the European Monitoring Centre for Drugs and Drug Addiction singles out pregabalin as a growing problem, with a fifth of all drug-related deaths in Ireland involving it – and 42 per cent of fatal poisonings in Finland.)
In New Zealand, the Suspected Medicine Adverse Reaction Search register shows 61 reports of 148 different reactions to gabapentin since 2016, including one death, and 41 reports of 116 reactions to pregabalin. Neither of Bailey's serious adverse reactions appears to have been reported and the real rate may be considerably higher.
By contrast, there have been 17 reports of adverse reactions to cannabis products since 2016, eight of them involving Sativex, which is not administered under the Medicinal Cannabis Scheme but is approved for distribution under the Medicines Act. Several appear to have been made in error (they report indications for treatment rather than adverse effects), and an interaction with the blood-thinner warfarin in a 76-year-old woman is the most serious reaction reported for a CBD-only product.
Bailey is still using the balm and says he feels better than he has in a long time.
"I don't feel really stoned. It just helps. I sleep at night, and I haven't done that for years because of the pain. I've smoked cannabis in the past, I'm not going to hide from that, but this definitely works better for the pain than smoking."
He has gone from thinking about ending his life to wanting to rejoin the workforce, he says.
"But I'd like prescription medication. So it's not illegal. So it's valid if I go for a job interview and have a drug test."
For now, he has no prospect of affording the hundreds of dollars a month unsubsidised prescription cannabis would cost. ACC takes applications to fund cannabis prescriptions, but invariably rejects them.
The system works better for people who can afford it. Auckland IT consultant Dan Salter, who injured his back in the most mundane of ways – putting out the washing – was tipped into cycle of prescriptions: codeine, tramadol, fentanyl. He lost weight and suffered chronic fatigue.
When he and his wife temporarily relocated back home to the UK so she could complete a doctorate, it was worse. NHS doctors were reluctant to prescribe strong opioids, "but they were willing to try various experimental stuff, gabapentin and that kind of stuff – limb-loss drugs. None of it had any effect, and ultimately it led to me collapsing. I just fell unconscious while talking, but I have no memory of it."
By the time they returned to New Zealand, the new medicinal-cannabis regime was operating. After a return spell on prescription opioids that he again found intolerable, he called the Cannabis Clinic in Auckland, where he was offered a treatment plan beginning with a CBD-only product.
"Within 48 hours of starting on the CBD oil, a lot of my secondary symptoms – not pain-related, but I get quite a severe tremor and I can stammer and slur, almost like I'm drunk – disappeared and didn't return."
He now manages his pain and other symptoms with CBD during the day and takes the THC product Tilray 25 at night, which lets him sleep. He likes the precision of prescribed cannabis, but not the "horrendous" cost of about $650 a month and the growing uncertainty of supply.
"With my personal pain-management plan, I've nailed it now. I know exactly what I'm getting, so I can plan it out. It's given me full control over my pain management, which I've never had before. I'm not saying it's a silver bullet, I'm not saying I don't feel pain – I live in pain constantly and it never goes away – but it allows those secondary symptoms to be managed. And it means I can stop it getting to a point where I'm laid out and I can't be a father or a husband or any of those other things."
Cannabis Clinic chief executive Dr Waseem Alzaher says he sees patients desperate to reduce their prescription load "every day".
"Recently, I had a lady who was struggling for years with insomnia and anxiety who was using benzodiazepines. They're very, very addictive drugs. She was using Zopiclone, the sleeping pill, and without any instruction from me and my GPs, she was able to almost stop those medications within two weeks of starting on THC. That, from a medical point of view, is basically a miracle. Getting people off these medications is almost impossible and they often just give up because it's too hard."
This isn't without its risks. Alzaher acknowledges that his clinic has learnt about dosing after several older patients who had never used cannabis before wound up distressed in emergency departments, but he says the risk of permanent harm from cannabis overdose is negligible compared with, say, paracetamol.
Over the next few years, it's likely that conventional clinical trials will more clearly show which specific cannabis products work and for what conditions. But until then, doctors and regulators may need to acknowledge that if using cannabis gets some patients with chronic conditions out from under the crushing weight of their prescribed medicines, then this benefit should be acknowledged rather than ignored.
Russell Brown has covered drug law and public health issues for a range of media organisations and for the New Zealand Drug Foundation. He was part of the "We Do" campaign for a Yes vote in the 2020 cannabis referendum.