Cannabinoid Studies Released

CANNABIS CULTURE – The state-funded California Center for Medicinal Cannabis Research announced that its studies have shown marijuana to have therapeutic value in a report released on February 17.

The ten-year, $8.7-million medical marijuana research program, established at the University of California in 2000, reported positive results in six different human clinical trials regarding chronic pain, spasticity and vaporization.

Four of the CMCR studies found cannabis effective in treating painful HIV neuropathy, (Ellis, 2009), neuropathic pain (Wilsey, 2008) and migraine headaches (Meng, 2003); and as a “modest analgesia” in capsaicin-induced pain (Wallace, 2007).

Using notoriously low-grade marijuana grown at the University of Mississippi, researchers were able to test cannabis with different THC contents. One study showed improved benefits with higher doses; another showed 4% and 7% THC were equally good, and better than placebo. In a study injecting a substance into the skin that mimics pain, the medium dose worked best, and the higher dose made it worse, suggesting a therapeutic window, CMCR director Igor Grant told KZYX radio in Ukiah.

“The findings are very consistent,” remarked Grant, “There is good evidence now that cannabinoids may be a good adjunct or even first line treatment.” Neuralgia is a type of pain caused by damaged nerves that is particularly resistant to other therapies. Some 10% of the population are said to be affected by neuralgia.

A fifth CMCR study found marijuana effective in reducing muscle spasticity in multiple sclerosis patients.

Grant suggested larger trials in the future, perhaps supported by the National Institutes of Health, which enrolls a more diverse group of patients, with respect to ages and backgrounds, who might respond differently to cannabis as they do other drugs.

Alternative delivery systems are also a potential area for further research, said Grant, particularly vaporization and oral forms of medication. A CMCR study has demonstrated the efficacy of smokeless vaporizers as an alternative delivery system to smoked marijuana.

Meanwhile, an excellent review of recent clinical studies conducted worldwide on the medical use of cannabis and cannabinoids has been published by Arno Hazekamp and Franjo Grotenhermen in the journal of the International Association for Cannabis Medicines. (Cannabinoids 2010; 5 (special issue): 1-21.) Picking up from a 2006 study by Canadian Ben Amar that summarized known cannabinoid studes from 1975 through June 2005, the authors summarize 37 different controlled studies involving 2563 patients in the period July 1, 2005 – August 1, 2009. Eight specifically involved smoked marijuana, all of which indicated medical efficacy.

Guzman et al.’s 2006 study showing inhibited tumor cell formation in brain cancer patients also showed cannabinoids could be safely delivered. A study of 71 Hep C patients smoking cannabis on their own account found modest use could help them adhere to their challenging medication regimen.

Of 15 studies conducted on neuropathic, chronic, or experimentally-induced pain, cannabis or cannabinoids were most effective on chronic, rather than acute or post-operative pain, with only mild or moderate adverse effects. Previous animal and human studies showing a synergistic effect between cannabinoids and opiates on pain control were not firmly confirmed in the more recent trials.

The largest patient cohort (1300) participated in 9 studies on multiple sclerosis and spasticity. Studies showed that Sativex, a sublingual whole plant extract, is effective in treating symptomatic pain, spasticity, and bladder control in MS patients, and can be used effectively in long-term care. Pathways by which cannabinoids work on pain were studied, and a 2009 Italian study showed Sativex did not induce psychopathology nor impair cognition in cannabis-naïve patients.

Serum levels of 100 MS patients taking Sativex did not find significant anti-inflammatory effects, which may be useful in treating MS, which is considered an autoimmune condition. Oral Cannador and dronabinol caused a significant reduction in incontinence in a study of 630 MS patients, and oral Nabilone provided significant reduction of pain but not spasticity in 11 MS patients with chronic upper motion motor neuron syndrome.

Four studies with 110 total patients have been conducted on HIV/AIDS in the last 5 years, all in the U.S., where dronabinol (oral THC) can be prescribed for AIDS wasting syndrome. In two studies, Haney found both smoked cannabis and oral dronabinol were well tolerated and produced substantial increases in food intake. Abrams et al found that smoked cannabis reduced daily pain significantly compared with a placebo, and Ellis found it significantly reduced neuropathic pain intensity.

In a British study, sublingual cannabis extract high in THC was shown to decrease intraocular eye pressure in a small number of glaucoma patients; a CBD-rich extract did not reduce IOP, and in a large dose actually increased it (Tomida et al, 2006).

Two studies of the effects of dronabinol on the intestinal dysfunction in healthy volunteers were conducted by Esfandyari et al. in the U.S. Both observed that THC significantly slowed gastric emptying, especially in females, and was associated with colon relaxation. The results could help explain marijuana’s anti-emetic effect, and lead to better treatment of irritable bowel syndrome.

An incomplete study by Strasser et al. did not find significant effects on appetite and quality of life in cancer patients with either oral THC and Cannador. Dronabinol, ondansetron (Zofran), and their combination was studied in post-chemotherapy patients by Meiri (2007). Either drug was equally effective, and combining them wasn’t beneficial and caused more dizziness and fatigue. Patients receiving THC had the most improved quality of life.

A preliminary study by Leweke (2007) compared oral CBD with the standard antipsychotic amisulpride (Solian) in schizophrenic patients and showed similar effectiveness and fewer side effects with CBD therapy. Intravenous THC had transient positive and negative effects on schizophrenic patients in a study by D’Souza et al (2007), which found that schizophrenics are also more susceptible to cognitive effects of THC.

The authors add that at least 110 human studies on medical cannabis have been published since 1975. Many more have been conducted in animals.

Paul Armentano, deputy director of NORML, has published an updated edition of his booklet, “Emerging Clinical Applications for Cannabis and Cannabinoids: A Review of the Recent Scientific Literature 2000-2009.” Armentano got a standing ovation for his presentation on the subject at the recent NORML conference in San Francisco, and is teaching courses at Oaksterdam University. He notes that over 1000 studies have been published on cannabinoids in the year 2006 alone, and 2100 in 2008, versus 1996 when only 258 scientific journals published cannabinoid studies.