Pubdate: Thu, 05 Jul 2001
Source: Guardian, The (UK)
Copyright: 2001 Guardian Newspapers Limited
Contact:  http://www.guardian.co.uk/guardian/
Details: http://www.mapinc.org/media/175
Author: Sarah Boseley, Health Editor
Bookmark: http://www.mapinc.org/mmj.htm (Cannabis - Medicinal)

RESEARCH CASTS DOUBT ON CANNABIS BENEFITS

Setback for calls to license pot, as derivatives cause side effects 
and prove less valuable than conventional drugs for pain relief.

Cannabis derivatives are neither as effective nor as safe as 
conventional medicines for the relief of pain and prevention of 
sickness during cancer drug treatment, according to two reviews of 
existing evidence which will dismay those who hope to see marijuana 
licensed as a medicine.

However, neither study focused on the possible benefit to people 
suffering from multiple sclerosis. Cannabis derivatives are being 
tested on substantial numbers of people with MS and other neuropathic 
disorders as a result of sufferers' claims that smoking dope relieved 
their symptoms and their pain.

Recently a House of Lords select committee urged the medicines 
control agency to help speed up the process of licensing cannabis 
derivatives. The MCA, however, has said it may require further tests 
on the toxicity of one of the cannabinoids - the chemicals derived 
from breaking down the whole plant.

The review published today in the British Medical Journal suggests 
that cannabinoids do have an effect in pain and sickness relief, but 
that it is not great, and it warns of serious side effects that 
outweigh the benefits.

The authors acknowledge, however, that multiple sclerosis - where 
there are few useful drugs - may be a special case. One trial, 
examined during the review of pain control, showed not only that 
people who smoked marijuana felt that their symptoms had improved, 
but that their posture and balance measurably improved.

Fiona Campbell, from the pain management centre of the Queen's 
medical centre in Nottingham, collaborated with colleagues in Oxford 
and Switzerland to review all the trials that have been done into 
cannabinoids for pain management. They found nine relevant and 
acceptable studies, of which five related to cancer pain, two to 
acute pain after surgery and two to chronic pain.

The researchers found that cannabinoids were no more effective than 
codeine tablets in controlling pain. They depressed the nervous 
system, which would limit their use. "Their widespread introduction 
into clinical practice for pain management is therefore undesirable. 
In acute postoperative pain they should not be used," the authors 
said.

They and the team who reviewed the use of cannabinoids to prevent 
sickness in people undergoing chemo therapy, or toxic drug treatment 
for cancer, were alarmed by the side effects of the cannabinoids. 
"Adverse effects associated with the cannabinoids were common and 
sometimes severe in six of the eight trials that showed efficacy," 
said Dr Campbell and colleagues.

The result of the review of the chemotherapy studies was otherwise a 
little more optimistic. Martin Tramer, an anaesthetist from the 
University hospital of Geneva, Switzerland, and colleagues from the 
Oxford Radcliffe hospital in the UK looked at the results of 30 
trials published between 1975 and 1997. They found the cannabinoids 
were slightly more effective than other drugs in preventing nausea 
and vomiting, and the patients preferred them. But the researchers 
said they caused so many damaging side effects that doctors would 
have to think hard about using them.

Tony Moffat of the Royal Pharmaceutical Society, who is on the 
steering committee for the trials of cannabinoids use in multiple 
sclerosis and pain relief funded by the Medical Research Council, 
said the papers were no reason to be dismayed; the trials had shown 
there was some effect in terms of pain relief.

The MRC pain relief trials, which will begin next month, involve 400 
patients who have had surgery in London hospitals. The multiple 
sclerosis trial involves 660 patients and is based in Derriford 
hospital, Plymouth. The first 20 patients have been treated with no 
adverse effects.

A second set of trials is taking place, run by the commercial company 
GW Pharmaceuticals, which has developed a spray from the entire 
cannabis plant which is applied under the tongue. The company is 
already claiming great success and says using the whole plant gets 
better results than stripping it down to derivative cannabinoids.

"In the last 18 months GW has carried out clinical trials in 75 
patients suffering from multiple sclerosis, spinal cord injury, 
neuropathic pain, other intractable neurological conditions and 
rheumatoid arthritis," said Philip Robson, the company's medical 
director. "We are seeing clinically significant improvements in a 
range of symptoms, including pain, muscle spasms, spasticity, bladder 
symptoms, tremor and overall improvements in quality of life. In some 
cases the improvement has been sufficient to transform lives."
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