IACM-Bulletin of January 21, 2007

Science UK — Cannabis extract effective in the treatment of neuropathic pain in two clinical studies

In a press release by the British company GW Pharmaceuticals of 15 January 2007 results of two clinical studies with the cannabis extract Sativex were presented, one in patients with neuropathic pain characterised by allodynia, the other in patients with painful diabetic neuropathy. In the first study the use of Sativex resulted in clinically important improvements in the management of pain and quality of sleep. The results of the study in patients with diabetic neuropathy show a less clear difference between the cannabis extract and placebo. Both studies focused on patients, who were already taking the best available pain treatments, and yet still suffered severe pain. The other pain medicines were maintained during the studies.

The first study included 246 patients with neuropathic pain characterised by allodynia. Allodynia is the occurrence of pain in response to a normally non-painful stimulus. The primary endpoint of the study, the proportion of patients responding to the treatment, was statistically significantly in favour of Sativex. In addition, two important secondary efficacy endpoints, the Patient’s Global Impression of Change and the assessment of sleep quality, were also statistically significantly in favour of Sativex.

The diabetic neuropathy study included 297 patients. In this study, patients taking Sativex showed a 30 per cent mean improvement in pain scores and one third of the patients achieved over a 50 per cent improvement in pain. However, the study results are difficult to interpret due to an abnormally large response in the placebo group. Although all outcome measures compared to placebo were in favour of Sativex, they did not reach statistical significance.

More at: http://www.gwpharm.com

(Source: GW Pharmaceuticals of 15 January 2007)

News in brief

USA — California

On 17 January federal agents raided 11 medical cannabis distribution centres in Los Angeles County. The simultaneous raids, part of an ongoing investigation by the federal Drug Enforcement Administration, were the largest such operation in the county in recent history. The action by federal agents angered some local officials and was taken despite a state law permitting possession and cultivation of cannabis for qualified patients. (Source: Los Angeles Times of 18 January 2007)

USA — South Carolina

A state senator whose first wife suffered a painful death wants the state to legalize medical cannabis use. Senator Bill Mescher said the issue has been on his mind for about 20 years. "My first wife died of lung cancer - a long agonizing death," the Republican said. A doctor said cannabis might help ease the pain and nausea from chemotherapy, but South Carolina law wouldn't allow it. However, Mescher isn't optimistic about the bill's chance given the drug's reputation. (Source: Associated Press of 16 January 2007)

Science — Spasticity

According to an animal study the control of spasticity in multiple sclerosis is mediated by CB1, not CB2 cannabinoid receptors. (Source: Pryce G, Baker D. Br J Pharmacol 2007 Jan 15; [Electronic publication ahead of print])

Science — Gastric ulcer and pancreatitis

According to animal research the activation of CB1 receptors evoked opposite effects in the stomach and pancreas. In the stomach, cannabinoids exhibited protective effects against stress-induced gastric ulcer, whereas in the pancreas, they increased the severity of pancreatitis induced by a chemical. (Source: Dembinski A, et al. J Physiol Pharmacol 2006;57 Suppl 5:137-54.)

Science — Self-medication

Danish and American scientists tested the self-medication hypothesis of depression and aggression in 119 cannabis-using subjects. They concluded from their research that subjects with prior depression do not use cannabis as a mean of self-medication. They are more likely to experience specific increases of adverse symptoms while under the influence of cannabis, and are less likely to experience specific symptom relief. According to the scientists, there is some evidence that cannabis is used as a means of self-medication for problems controlling aggression. (Source: Arendt M, et al. Psychol Med 2007;1-11.)

Science — Herpes zoster

In an animal model of pain associated with herpes zoster infection several drugs were tested for efficacy to reduce pain. The following drugs were effective: morphine, amitriptyline, gabapentin, ibuprofen and the synthetic cannabinoid WIN55,212-2. (Source: Hasnie FS, et al. Neuroscience 2006 Dec 28; [Electronic publication ahead of print])