A new, small clinical trial1 reports positive results using a drug for multiple sclerosis that is not approved for use in the United States, but was okayed by Canadian regulatory authorities earlier this year.
The medication, known as Sativex, is made of two ingredients from marijuana plants known as THC (tetrahydrocannabinol) and cannabidiol. It's given to patients as a mouth spray.
Anecdotal Reports
Marijuana, though banned as a treatment for MS in the United States, has been reported to be an effective therapy to relieve symptoms of the disease by some patients. In one survey,2 nearly three-quarters of patients supported legalizing the medicinal use of marijuana. Nearly half of these same patients had reported they had used pot at least one time, and 16 percent of those for therapeutic reasons. The patients reported that the plant relieved anxiety and depression, as well as spasticity and pain related to their MS.2
There are exceptions to the US law banning marijuana use. For example, lawmakers in Washington State allow limited possession of the plant, as long as the individual using it provides a note from their physician or a copy of their medical records stating that they have a condition that may benefit from the drug's use.3
Marijuana-Based Medicine Tested
In this trial, doctors at several medical institutions in Liverpool, England recruited nearly 70 people with multiple sclerosis to test the safety and efficacy of Sativex. The patients had been experiencing moderate to severe central neuropathic pain that had not been relieved by other medications.
"Central neuropathic pain occurs frequently in people with MS," said Carolyn Young, MD, the study's chief investigator and a Consultant Neurologist at the Walton Centre for Neurology and Neurosurgery in Liverpool. "It can be tremendously debilitating and unresponsive to existing therapies."
Patients were divided at random into groups that received either Sativex or a spray like Sativex, but without the therapeutic effect.
Patients were instructed to take the medication as often as they wished to a maximum of 48 sprays in any one 24-hour period.
The trial, which ran for five weeks, involved 34 patients who were taking Sativex, and the rest taking a placebo spray. By the fourth week of the study, most patients, on average, had used about 9 sprays in a 24-hour period, though the range was two to 25 sprays. Of those taking a placebo, the average number of sprays in 24 hours was about 19 with a range of 1 spray to 47 sprays.
Patients who experienced intoxication were advised to reduce or omit a dose.
The researchers then measured each patient's level of pain and spasticity using a rating scale. They also tested for changes in cognitive function, and asked patients whether they had perceived any changes in their overall health during the five-week study.
Symptom Relief Reported
At the end of the study, the investigators reported that Sativex reduced the average intensity of pain by nearly twice as the placebo spray. Patients on the medication also reported that they were able to sleep better, on average, than those taking the placebo.
"The cannabis-based medicine was generally well tolerated, although more patients on cannabis-based medicine than placebo reported dizziness, dry mouth, and [sleepiness]," the research investigators wrote. About 88 percent of the patients on the medication experienced these side effects compared to about 69 percent of those on the placebo. Those on Sativex also reported negative impacts on their long-term memory.
Still, the study investigators concluded the drug did provide some level of relief. "Our findings demonstrate that Sativex was effective in reducing both central pain in MS and pain-related sleep disturbance in a population with moderate to severe central pain inadequately relieved by existing medication," Young stated.
More Evidence Needed: Experts
Meanwhile, GW Pharmaceuticals, which manufactures Sativex, reports the medication is currently undergoing an additional clinical trial in the United Kingdom.
"Based on studies conducted to date, there are currently insufficient data to recommend marijuana or its derivatives as a treatment for MS," said John Richert, MD, Vice-President of Research and Clinical Programs at the National MS Society, who was not involved in the Liverpool study. "We look forward to more extensive studies evaluating long-term benefits and risks."
1. Rog DJ, Nurmikko TJ, Friede T, Young CA. Randomized, controlled trial of cannabis-based medicine in central pain in multiple sclerosis. Neurology 2005 Sep 27;65(6):812-9.
2. Page SA, Verhoef MJ, Stebbins RA, Metz LM, Levy JC. Cannabis use as described by people with multiple sclerosis. An J Neurol Sci 2003 Aug;30(3):201-5.
3. Schouten JT. Medical marijuana: legal considerations. STEP Perspect 1999 Summer;99(2):5.
John Martin is a long-time health journalist and an editor for Priority Healthcare. His credits include overseeing health news coverage for the website of Fox Television's The Health Network, and articles for the New York Post and other consumer and trade publications. 
