Mixed findings regarding quality of evidence supporting benefit of medical marijuana
June 23, 2015
Science Daily/JAMA - Journal of the American Medical Association
In an analysis of the findings of nearly 80 randomized trials that included about 6,500 participants, there was moderate-quality evidence to support the use of cannabinoids (chemical compounds that are the active principles in cannabis or marijuana) for the treatment of chronic pain and lower-quality evidence suggesting that cannabinoids were associated with improvements in nausea and vomiting due to chemotherapy, sleep disorders, and Tourette syndrome, according to a study in the June 23/30 issue of JAMA.
Medical cannabis refers to the use of cannabis or cannabinoids as medical therapy to treat disease or alleviate symptoms. In the United States, 23 states and Washington, D.C., have introduced laws to permit the medical use of cannabis; many other countries have similar laws. Despite the wide us of cannabis and cannabinoid drugs for medical purposes, their efficacy for specific indications is not clear, according to background information in the article.
Penny F. Whiting, Ph.D., of the University of Bristol, Bristol, United Kingdom, and colleagues evaluated the evidence for the benefits and adverse events (AEs) of medical cannabinoids by searching various databases for randomized clinical trials of cannabinoids for a variety of indications. The researchers identified 79 trials (6,462 participants) that met criteria for inclusion in the review and meta-analysis.
The researchers found that most studies suggested that cannabinoids were associated with improvements in symptoms, but these associations did not reach statistical significance in all studies. There was moderate-quality evidence to suggest that cannabinoids may be beneficial for the treatment of chronic neuropathic or cancer pain and spasticity due to multiple sclerosis (sustained muscle contractions or sudden involuntary movements). There was low-quality evidence suggesting that cannabinoids were associated with improvements in nausea and vomiting due to chemotherapy, weight gain in HIV, sleep disorders, and Tourette syndrome; and very low-quality evidence for an improvement in anxiety. There was low-quality evidence for no effect on psychosis and very low-level evidence for no effect on depression.
There was an increased risk of short-term AEs with cannabinoids, including serious AEs. Common AEs included dizziness, dry mouth, nausea, fatigue, somnolence, euphoria, vomiting, disorientation, drowsiness, confusion, loss of balance, and hallucination. There was no clear evidence for a difference in association (either beneficial or harmful) based on type of cannabinoids or mode of administration. Only 2 studies evaluated cannabis. There was no evidence that the effects of cannabis differed from other cannabinoids.
"Further large, robust, randomized clinical trials are needed to confirm the effects of cannabinoids, particularly on weight gain in patients with HIV/AIDS, depression, sleep disorders, anxiety disorders, psychosis, glaucoma, and Tourette syndrome are required. Further studies evaluating cannabis itself are also required because there is very little evidence on the effects and AEs of cannabis," the authors write.
Editorial: Medical Marijuana
"If the states' initiative to legalize medical marijuana is merely a veiled step toward allowing access to recreational marijuana, then the medical community should be left out of the process, and instead marijuana should be decriminalized," write Deepak Cyril D'Souza, M.B.B.S., M.D., and Mohini Ranganathan, M.D., of the Yale University School of Medicine, New Haven, Conn., in an accompanying editorial.
"Conversely, if the goal is to make marijuana available for medical purposes, then it is unclear why the approval process should be different from that used for other medications. Evidence justifying marijuana use for various medical conditions will require the conduct of adequately powered, double-blind, randomized, placebo/active controlled clinical trials to test its short- and long-term efficacy and safety. The federal government and states should support medical marijuana research. Since medical marijuana is not a life-saving intervention, it may be prudent to wait before widely adopting its use until high-quality evidence is available to guide the development of a rational approval process."
https://www.sciencedaily.com/releases/2015/06/150623113152.htm
No strong evidence to back use of cannabis extract in multiple sclerosis
December 12, 2012
Science Daily/BMJ-British Medical Journal
There is no strong evidence to back the use of cannabis extract in the treatment of Multiple Sclerosis (MS), concludes a review of the available evidence on the first licensed preparation, published in the December issue of Drug and Therapeutics Bulletin (DTB).
Sativex, in the form of a mouth spray, contains the principal extracts -- dronabinol and cannabidiol -- found in the leaf and flower of the cannabis plant. It is the first cannabinoid preparation to be licensed for use in the treatment of muscle spasms in MS.
MS is estimated to affect around 60,000 people in England and Wales, and around one in every 1000 people will develop the condition in the UK.
An increase in muscle tone, or spasticity is a common symptom of the condition, causing involuntary spasms, immobility, disturbed sleep, and pain.
Complex combinations of drugs are sometimes needed to manage spasticity, but they don't work that well and have a range of unpleasant side effects.
Sativex is intended for use as a second line treatment in patients in whom these other options have failed. But the DTB review found that the trial data on which the success of Sativex is based, are limited.
Overall, the trials, on which the drug's approval was based, did show a small difference in the numbers of patients who in whom symptoms abated compared with those taking a dummy (placebo) preparation.
But in many of these studies, Sativex was used for relatively short periods -- from six weeks to four months. And none included an active ingredient with which the effects of Sativex could be compared.
Two of the trials included doses that exceeded the 12 daily sprays for which the preparation is licensed. One trial did not have sufficient numbers of participants to validate the results.
A third trial, which was properly designed, and did have sufficient numbers of participants, did not find any significant difference in symptom relief between those who took Sativex and those who didn't.
The preparation is also expensive, notes DTB, and costs around 10 times as much as other drugs used for the secondary treatment of MS muscle spasms.
As yet, the body that advised the NHS on its use of treatments, the National Institute for Health and Clinical Excellence (NICE) has not offered any advice on the use of cannabis extract either, although it is set to do so.
But the DTB review says that the strength of the evidence is insufficient to warrant its routine use. "We believe that such limitations make it difficult to identify the place of this product in clinical practice," it concludes. Commenting on the review, GP and DTB editor, James Cave, said the findings of the review were "disappointing."
"MS is a serious and disabling condition, and it would be great to say that this drug could make a big difference, but the benefit is only modest," he said.
https://www.sciencedaily.com/releases/2012/12/121212205729.htm
Can Cannabis Compounds Slow the Progression of Multiple Sclerosis?
July 21, 2008
Science Daily/The Peninsula College of Medicine and Dentistry
The CUPID (Cannabinoid Use in Progressive Inflammatory brain Disease) study at the Peninsula Medical School in Plymouth has reached an important milestone with the news that the full cohort of 493 people with multiple sclerosis (MS) has been recruited to the study.
CUPID is a clinical trial which will evaluate whether tetrahydrocannabinol (THC), one of many compounds found in the in the cannabis plant (and the main active ingredient) is able to slow the progression of MS.
This is an important study for people with MS because current treatments either target the immune system in the early stages of MS, or are aimed at easing specific symptoms such as muscle spasms or bladder problems. At present there is no treatment which slows progression of the disease.
The CUPID trial follows an earlier study -- Cannabinoids and Multiple Sclerosis (CAMS) -- which suggested a link between THC and the slowing of MS. The CAMS trial saw participants take THC for a year -- the CUPID trial will last for longer and aims to assess the effect of THC on progressive MS.
It has taken two years to recruit the 493 participants who will each take part in the trial for three years, and in some cases three and a half years. After data cleaning and analysis the results should be available by spring/early summer 2012.
Professor John Zajicek from the Peninsula Medical School, who heads the team carrying out the CUPID study, said: "We are delighted to have achieved the correct number of patient participants for this trial. Patients have been recruited from 27 sites across the UK. If we are able to prove beyond reasonable doubt the link between THC and the slowing down of progressive MS, we will be able to develop an effective therapy for the many thousands of MS sufferers around the world."
The CUPID trial is funded by the Medical Research Council, the Multiple Sclerosis Society and the Multiple Sclerosis Trust.
Chris Jones, chief executive of the MS Trust, commented: "The MS Trust is delighted to be supporting this study on behalf of people with MS. The ability to halt progression in MS is what we dream of - the Holy Grail for those whose condition deteriorates year on year. This study should give us the definitive answer as to whether cannabinoids will prove to be such an agent."
Dr Laura Bell, research communications officer for the MS Society, said: "People affected by MS are keen to know whether there's any truth in the suggestion that elements of the cannabis plant can help ease the symptoms and slow down progression of the condition.
"The MS Society is supportive of safe clinical trials investigating the medicinal properties of cannabis and it's great news that this trial is going ahead. We look forward to the results of this exciting study."
https://www.sciencedaily.com/releases/2008/07/080721114608.htm
Smoking Marijuana Impairs Cognitive Function in MS Patients
February 14, 2008
Science Daily/American Academy of Neurology
People with multiple sclerosis (MS) who smoke marijuana are more likely to have emotional and memory problems, according to new research.
"This is the first study to show that smoking marijuana can have a harmful effect on the cognitive skills of people with MS," said study author Anthony Feinstein, MPhil, PhD, of the University of Toronto. "This is important information because a significant minority of people with MS smoke marijuana as a treatment for the disease, even though there are no scientific studies demonstrating that it is an effective treatment for emotional difficulties."
Feinstein noted that MS itself can cause cognitive problems. "In addition, cognitive problems can greatly affect the quality of life for both patients and their caregivers," he said.
For the study, researchers interviewed 140 Canadian people with MS. Of those, 10 people had smoked marijuana within the last month and were defined as current marijuana users. The marijuana users were then each matched by age, sex, the length of time they had MS, and other factors to four people with MS who did not smoke marijuana.
The researchers then evaluated the participants for emotional problems such as depression, anxiety and other psychiatric disorders. They also tested the participants' thinking skills, speed at processing information, and memory.
The study found marijuana smokers performed 50 percent slower on tests of information processing speed compared to MS patients who did not smoke marijuana. There was also a significant association between smoking marijuana and emotional problems such as depression and anxiety.
People with MS have higher rates of depression and suicide compared to the general population. "Since marijuana can induce psychosis and anxiety in healthy people, we felt it was especially important to look at its effects on people with MS," Feinstein said.
This research was published February 13, 2008, in the online edition of Neurology®, the medical journal of the American Academy of Neurology. The study was supported by a grant from the Canadian Institutes for Health Research.
https://www.sciencedaily.com/releases/2008/02/080213160851.htm
Sending multiple sclerosis up in smoke
October 7, 2013
Science Daily/American Friends of Tel Aviv University
In a new study, researchers demonstrate that some chemical compounds in marijuana can help treat multiple sclerosis and similar diseases in mice by preventing inflammation in the brain and spinal cord, holding promise for new treatments in humans as well.
Multiple sclerosis is an inflammatory disease in which the immune system attacks the nervous system. The result can be a wide range of debilitating motor, physical, and mental problems. No one knows why people get the disease or how to treat it.
In a new study published in the Journal of Neuroimmune Pharmacology, Drs. Ewa Kozela, Ana Juknat, Neta Rimmerman and Zvi Vogel of Tel Aviv University's Dr. Miriam and Sheldon G. Adelson Center for the Biology of Addictive Diseases and Sackler Faculty of Medicine demonstrate that some chemical compounds found in marijuana can help treat MS-like diseases in mice by preventing inflammation in the brain and spinal cord.
"Inflammation is part of the body's natural immune response, but in cases like MS it gets out of hand," says Kozela. "Our study looks at how compounds isolated from marijuana can be used to regulate inflammation to protect the nervous system and its functions." Researchers from the Weizmann Institute of Science co-authored the study.
Mind-altering findings
Israel has a strong tradition of marijuana research. Israeli scientists Raphael Mechoulam and Yechiel Gaoni discovered THC, or tetrahydrocannabinol, in 1964, kick-starting the scientific study of the plant and its chemical constituents around the world. Since then, scientists have identified about 70 compounds -- called cannabinoids -- that are unique to cannabis and have interesting biological effects. In the 1990s, Prof. Vogel was among the first researchers to describe endocannabinoids, molecules that act like THC in the body.
Besides THC, the most plentiful and potent cannabinoid in marijuana is cannabidiol, or CBD. The TAU researchers are particularly interested in CBD, because it offers medicinal benefits without the controversial mind-altering effects of THC.
In a 2011 study, they showed that CBD helps treat MS-like symptoms in mice by preventing immune cells in their bodies from transforming and attacking the insulating covers of nerve cells in the spinal cord. After inducing an MS-like condition in mice -- partially paralyzing their limbs -- the researchers injected them with CBD. The mice responded by regaining movement, first twitching their tails and then beginning to walk without a limp. The researchers noted that the mice treated with CBD had much less inflammation in the spinal cord than their untreated counterparts.
High hopes for humans
In the latest study, the researchers set out to see if the known anti-inflammatory properties of CBD and THC could also be applied to the treatment of inflammation associated with MS -- and if so, how. This time they turned to the immune system.
The researchers took immune cells isolated from paralyzed mice that specifically target and harm the brain and spinal cord, and treated them with either CBD or THC. In both cases, the immune cells produced fewer inflammatory molecules, particularly one called interleukin 17, or IL-17, which is strongly associated with MS and very harmful to nerve cells and their insulating covers. The researchers concluded that the presence of CBD or THC restrains the immune cells from triggering the production of inflammatory molecules and limits the molecules' ability to reach and damage the brain and spinal cord.
Further research is needed to prove the effectiveness of cannabinoids in treating MS in humans, but there are reasons for hope, the researchers say. In many countries, CBD and THC are already prescribed for the treatment of MS symptoms, including pain and muscle stiffness.
"When used wisely, cannabis has huge potential," says Kozela, who previously studied opiates like morphine, derived from the poppy plant. "We're just beginning to understand how it works."
https://www.sciencedaily.com/releases/2013/10/131007132253.htm