Nearly 40 years after cannabis was banned, a proposed cahnge in the law looks set to clear it for medicinal use. But just how useful is the drug - and how safe?
The Independent - United Kingdom ; 13-Jul-2000 12:00:00 am
Historical rumour has it that Queen Victoria was a keen proponent of cannabis, apparently using it for the relief of period pains. Sir John Russell Reynolds, for many years her personal physician, wrote extensively on the benefits of taking cannabis, and in Victorian times the herb was widely used to treat a variety of ailments and conditions, including muscle spasms, menstrual cramps and rheumatism.
Now, 150 years later, the situation is very different. Cannabis is illegal. Not only is it outlawed in Britain as a class-B drug; the herb, which is referred to in the oldest surviving text on medical drugs - the 5,000- year-old Chinese Shen-Nung Pen-tsao - is banned for all medical purposes.
But the phoenix is rising from the ashes. After a dormancy of almost 30 years since the total ban in 1971, a private member's Bill for the legalisation of cannabis for medical purposes is currently going through Parliament; its second reading is scheduled for later this month and has the signed support of 100 MPs. Should the Bill go through, cannabis may become immediately available as a treatment for illnesses such as multiple sclerosis. Research in the UK is abuzz with testing for its therapeutic gains. For conditions from asthma to migraines, cannabis could be the treatment of tomorrow.
Lester Grinspoon is associate professor of psychiatry at Harvard Medical School, in the United States. He is co-author of the book Cannabis the Forbidden Medicine and is one of many medical professionals across the world who believe that there is sufficient proof that cannabis is legitimate for medicinal purposes.
Dr Grinspoon explained: "It has been well known for thousand of years that cannabis has medical uses. It is far safer than most medicines prescribed by doctors daily and often works for patients who cannot tolerate the side-effects of other drugs. In many cases no other drug will do the job as safely or as well."
The list of illnesses that cannabis has been used to treat, from both historical and contemporary evidence, is impressive. Dr Grinspoon continued: "Clinical experience suggests that it is helpful for patients with severe nausea and vomiting, arthritis, glaucoma, muscle spasms, pre-menstrual syndrome, seizure disorders, the Aids weight-loss syndrome, asthma, fibromyalgia, Tourette's syndrome and depression, to name a few."
Doctors have known of the medicinal benefits of cannabis for decades. Two drugs based on its active ingredient - tetrahydrocannabinol, or THC - have been used in Britain for over 30 years to treat nausea in cancer patients who are undergoing chemotherapy, although their use has declined as newer drugs have taken their place.
Interest in other medicinal uses of cannabis is growing. There are at least 60 psychoactive substances among the 400 chemicals contained in the drug. The aim of research is to extract the active constituents of cannabis - in the same way that morphine was extracted from opium - to establish which are of benefit.
A 1997 report by the British Medical Association's board of science, "Therapeutic Uses of Cannabis", concluded that there was evidence that the drug could help muscle spasm in patients with multiple sclerosis. There was also limited evidence of benefits in epilepsy, glaucoma, asthma, high blood pressure and the weight-loss associated with Aids.
The BMA stressed it was not advocating use of the whole cannabis plant, which could be as damaging as tobacco, if not more so, but wanted research to determine which of the plant's 400 chemical constituents might bring medical benefits. However, in the meantime, it called on the courts to show compassion to people using the drug for medicinal reasons.
As you read this, there are about 40,000 cannabis plants being cultivated at a secret location in the south of England for precisely that purpose. GW Pharmaceuticals was set up in December 1997, after discussions with UK government officials, by Geoffrey Guy, who has 18 years' experience in pharmaceutical development, with the sole purpose of conducting medical research on cannabis.
Because of the illegality of using cannabis for medical purposes, any research has to be conducted with the Home Office's permission. To conduct in-depth research, the company has been granted two licences: a cultivation licence, which allows it to grow cannabis in a highly secure glasshouse facility, and a licence for possession and supply for medical research, which - as the name suggests - allows the company to dispense cannabis preparations for the purpose of research.
But after 5,000 years of historical accounts and reams of anecdotal evidence - why all this additional investigation? Why should we not just light up a spliff at the first inkling of a toothache?
The BMA's findings cite that smoking a cannabis cigarette - containing only herbal cannabis - leads to three times more tar inhalation than from smoking a tobacco cigarette. Chronic smoking of cannabis can increase the risk of smoking-related illnesses - such as cardiovascular disease, bronchitis and emphysema - threefold. Other potential dangers of long- term use include the suppression of ovulation in women, a decreased sperm count in men, sedation and anxiety.
Research into the administration of cannabis via alternative, safer methods is already under way. GW Pharmaceuticals has developed a number of delivery methods, including sub-lingual sprays and drops and aerosols and vaporisers for inhalation. The benefits of such methods are that they avoid smoking and allow the cannabinoids to be absorbed straight into the bloodstream.
By the time the herb has been fully developed for medicinal use, it is likely that its psychotropic effects will have been eliminated. In other words, if you are going to be using it as a medicine in the future, you are not going to be getting high.
Dr Guy believes that the psychoactive effect is an unwanted effect. He said: "There is a false assumption that multiple sclerosis sufferers, for example, who use cannabis get high and don't care about the pain. That is not what happens.
"People who are taking part in our trials are ordinary people who want relief from the pain and other symptoms such as spasm. They just want to get on with their lives. They want to go to the supermarket and do simple things, and you can't do that if you are suffering from unwanted psychoactive side-effects."
Roger Pertwee, of Aberdeen University, who has dedicated years of scientific study to cannabis, seconds his view. He explained: "I've seen anecdotal claims that you don't need to get high to feel better. Usually people are not seeking to get high; they are just using it to treat their symptoms. I would imagine that for some people getting high is a real nuisance. It might be fun on the odd occasion, but every day it would get rather boring."
The sub-lingual and inhalation methods developed by GW Pharmaceuticals will ensure a sufficiently low dosage to eliminate the psychotropic effects but still provide quick, effective pain relief.
Earlier this month, another breakthrough for administering cannabis was achieved by a team of scientists at Imperial College, University of London. They showed that cannabinoids act on the spinal cord as well as the brain. The finding paves the way for the development of new cannabinoid-based drugs that target the spinal cord to fight pain but bypass the brain and so, again, do not cause the high.
So what happens next? GW Pharmaceuticals estimates that a cannabis-based medicine will be available in 2003. Dr Guy predicts that it will be treated in the same way as morphine. "Morphine, which is used as a painkiller for cancer, is a dangerous substance. But under the right conditions, nobody would suggest that we couldn't prescribe morphine. What we are keen to do is to see if cannabis should occupy the same shelf in the pharmacist's cupboard as morphine does."
So, if and when a cannabis-based medicine becomes available, it is unlikely to bear much similarity to what Queen Victoria would have put in her pipe.
A cure-all for the future? The potential medical uses for cannabis
Asthma: a report issued by the select committee for science and technology of the House of Lords in 1998 acknowledged that cannabinoids seemed to work as effectively as conventional treatments for asthma.
Anorexia: trials have shown oral tetrahydracannabinol (THC) to be effective as an appetite stimulant in patients suffering from Aids-related appetite loss. Studies showed that patients benefited from substantial weight gain. That led to its legalisation in the USA in 1992. The BMA has recommended that it be licensed in the UK to treat anorexia in patients with cancer or Aids.
Arthritis: cannabis's pain-reducing properties are well documented, and emerging evidence suggests it has anti-inflammatory qualities. Dale Gieringer, American author of the paper "Review of Human Studies on the Medical Use of Marijuana" cites three studies documenting cannabis's potential anti-inflammatory properties.
Glaucoma: a report by the Institute of Medicine in the USA acknowledged cannabis's potential as a cure, stating: "High intra-ocular pressure is a high risk factor for glaucoma and can be reduced by cannabinoids and marijuana."
High blood pressure: research is being done at the University of Nottingham medical school on the effects on circulation produced by endocannabinoids, cannabis-like chemicals produced by the body. Scientists recently discovered that the endocannabinoid anandamide relaxes blood vessels, which can reduce blood pressure and allow it to flow more freely.
Migraine: a recent article in the medical journal Pain (Journal of the Association for the Study of Pain) concluded: "Cannabis, delivered in the form of a marijuana cigarette, or `joint', presents the hypothetical potential for quick, effective, parenteral [non-ingested] treatment of acute migraine."
Multiple sclerosis: the House of Lords science and technology select committee endorsed cannabis's ability to mitigate symptoms of MS. The committee chairman, Lord Perry of Walton, stated: "We have seen enough evidence to convince us that a doctor might legitimately want to prescribe cannabis to relieve the symptoms of MS and that the criminal law should not stand in the way."
Source: the Medical Cannabis Research Foundation (www.helpcannabisresearch.com)