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IACM-Bulletin of February 4, 2007

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World โ€” WHO expert committee recommends reclassification of dronabinol

The WHO Expert Committee on Drug Dependence (ECDD) met in Geneva from 28 to 31 March 2006. It recommended that dronabinol (THC) should be rescheduled from Schedule II to the less restrictive Schedule III of the 1971 Convention on Psychotropic Substances of the United Nations. This recommendation will be made to the United Nations Commission on Narcotic Drugs (CND), which may accept or reject this recommendation.

Dronabinol is the international non-proprietary name (INN) for THC, a natural cannabinoid in the cannabis plant, which is mainly responsible for its psychological and most of its therapeutic effects. Dronabinol was included in Schedule I of the 1971 Convention at the time of its adoption. It was rescheduled to Schedule II by the United Nations Commission on Narcotic Drugs in 1991.

According to the ECDD the abuse of dronabinol is currently rare and there have been very few specific reports of its occurrence. Dronabinol preparations have been used in several countries in the treatment of nausea and vomiting associated with cancer chemotherapy and in the treatment of anorexia associated with weight loss in patients with AIDS. It has also been indicated in the treatment of chronic pain and neurological disorders.

The ECDD report on its 2006 meeting is available at:

http://www.who.int/entity/medicines/areas/quality_safety/WHO_TRS_942.pdf

(Source: Information by ECDD of 29 January 2007)

News in brief

Science โ€” Pain

According to a meta-analysis on single cannabinoids and cannabis in neuropathic pain of MS patients cannabis-based medications are effective in treating this condition. The study included six articles and one controlled trial report, of which four examined the cannabis extract Sativex (with 196 patients), five cannabidiol (41 patients) and three THC (91 patients). (Source: Iskedjian M, et al. Curr Med Res Opin 2007;23(1):17-24.)

Science โ€” Amyotrophic lateral sclerosis

A synthetic cannabinoid, which selectively binds to the CB2 receptor, was shown to prolong survival in a mouse model of amyotrophic lateral sclerosis (ALS). ALS is a neurodegenerative disease causing death usually within less than five years after disease onset. Daily injections of the selective CB2 agonist AM-1241 to the mice increased the survival interval after disease onset by 56 per cent. Researchers concluded, that "CB2 agonists may slow motor neuron degeneration and preserve motor function, and represent a novel therapeutic modality for treatment of ALS." (Source: Shoemaker JL, et al. J Neurochem 2007 Jan 4; [Electronic publication ahead of print])

Science โ€” Tetrahydrocannabivarin (THCV)

Synthetic delta-8-tetrahydrocannabivarin (delta-8-THCV) and delta-9-tetrahydrocannabivarin (delta-9-THCV) were shown to antagonise the effects of THC in mice. This research followed earlier work, which had demonstrated that delta-9-THCV of the cannabis plant behaves as an antagonist at the CB1 receptor. (Source: Pertwee RG, et al. Br J Pharmacol 2007 Jan 22; [Electronic publication ahead of print])

Science โ€” Cannabidiol

In experiments with several tissues it was demonstrated that cannabidiol (CBD) behaves as an antagonist at the CB1 and the CB2 receptor. (Source: Thomas A, et al. Br J Pharmacol 2007 Jan 22; [Electronic publication ahead of print])

Economy โ€” GW Pharmaceuticals

According to a report by the press agency Reuters human trials of an experimental treatment for obesity derived from cannabis are scheduled to begin in the second half of this year, the British company GW Pharmaceuticals announced on 30 January. The report does not mention the main compound of this treatment. Since synthetic cannabinoid receptor antagonists such as rimonabant have been shown to reduce weight in clinical trials, it is expected that either tetrahydrocannabivarin (THCV) or cannabidiol (CBD), which are natural cannabinoid receptor antagonists, will be compounds of this treatment. (Source: Reuters of 30 January 2007)

Science โ€” Anxiety, depression and bipolar disorder

According to a 10-year prospective study of the Max Planck Institute of Psychiatry in Munich, Germany, with 1,395 subjects aged 14-17 years at onset of the study cannabis use was associated with anxiety disorders, depression and bipolar disorder. (Source: Wittchen HU, et al. Drug Alcohol Depend 2007 Jan 24; [Electronic publication ahead of print])

Science โ€” Sickle cell disease

According to a survey on patients with sickle cell disease in Jamaica the prevalence of cannabis use in this population is high. Its usage was unrelated to clinical severity of the disease. (Source: Knight-Madden J, et al. West Indian Med J 2006;55(4):224-7.)

Science โ€” Stroke

In an animal study the administration of a synthetic selective CB2 receptor agonist was associated with decreased infarct size and improved motor function compared to non-treated animals in a model of stroke. (Source: Zhang M, et al. J Cereb Blood Flow Metab 2007 Jan 24; [Electronic publication ahead of print])

Science โ€” THC acid

THC acid is the precursor of THC in the cannabis plant. It is transformed to THC by heat or other means. German researchers detected THC acid in blood and urine of cannabis users, which is indicative of incomplete transformation of THC acid to THC. Since only THC causes the characteristic effects of cannabis it is important that a high percentage of THC acid is transformed into THC to achieve the desired effects. (Source: Jung J, et al. J Mass Spectrom 2007 Jan 12; [Electronic publication ahead of print])