IACM-Bulletin of June 11, 2006

Science — THC reduces pain due to fibromyalgia in pilot study

The effect of oral THC was investigated in nine patients with fibromyalgia in a study at the Department of Anaesthesiology and Intensive Care Medicine of the University Hospital in Mannheim. Fibromyalgia is a chronic pain syndrome of unknown origin. In the four participants who completed the three-month study pain was reduced by 67 per cent on average. All four experienced a pain reduction by more than 50 per cent.

All pain medication was stopped 3 weeks prior to the investigation. In the study, patients received a daily oral dose of 2.5–15 mg THC. Starting with 2.5 mg the dosage was increased weekly by 2.5 mg THC, as long as no severe side effects were reported. Once a week, 24 hours after the last THC medication and a day before any dose increase, an electrical induced pain was caused. Moreover, the pain intensity was daily recorded by means of a numeric pain scale with the endpoints 0 (no pain) and 10 (maximum pain imaginable).

Five of the nine participants terminated the study before reaching the maximum dose of 15 mg due to severe side effects, primarily sedation, dizziness, fatigue or continuous tiredness. The experimentally induced pain was significantly reduced by THC in a dose of 10 and 15 mg. Daily recorded pain intensity was reduced from 8.1 on average at the beginning of the study to 2.8 after three months.

(Source: Schley M, Legler A, Skopp G, Schmelz M, Konrad C, Rukwied R. Delta-9-THC based monotherapy in fibromyalgia patients on experimentally induced pain, axon reflex flare, and pain relief. Curr Med Res Opin 2006;22(7):1269-1276 [electronic publication ahead of print])

Science — Cannabidiol inhibits tumour growth in leukaemia and breast cancer in animal studies

Italian researchers investigated the anti-tumour effects of five natural cannabinoids of the cannabis plant (cannabidiol, cannabigerol, cannabichromene, cannabidiol-acid and THC-acid) in breast cancer. Cannabidiol (CBD) was the most potent cannabinoid in inhibiting the growth of human breast cancer cells that had been injected under the skin of mice. CBD also reduced lung metastases deriving from human breast cancer cells that had been injected into the paws of the animals.

Researchers found that the anti-tumour effects of CBD were caused by induction of apoptosis (programmed cell death). They concluded that their data "support the further testing of cannabidiol and cannabidiol-rich extracts for the potential treatment of cancer."

These observations are supported by investigations of US scientists who found out that exposure of leukaemia cells to CBD led to a reduction in cell viability and induction of apoptosis. In living animals CBD caused a reduction in number of leukaemia cells. The scientists noted that CBD "may be a novel and highly selective treatment for leukemia."

(Sources: Ligresti A, Schiano Moriello A, Starowicz K, Matias I, Pisanti S, De Petrocellis L, Laezza C, Portella G, Bifulco M, Di Marzo V. Anti-tumor activity of plant cannabinoids with emphasis on the effect of cannabidiol on human breast carcinoma. J Pharmacol Exp Ther. 2006 May 25; [electronic publication ahead of print]; McKallip RJ, Jia W, Schlomer J, Warren JW, Nagarkatti PS, Nagarkatti M. Cannabidiol-induced apoptosis in human leukemia cells: A novel role of cannabidiol in the regulation of p22phox and Nox4 expression. Mol Pharmacol. 2006 Jun 5; [electronic publication ahead of print])

News in brief

USA — South Dakota

Citizens of South Dakota will decide in November 2006 whether seriously ill patients may be allowed to use cannabis for medical purposes in the state. The measure to be decided on would allow qualified patients to possess up to six plants and/or one ounce (28.5 grams) of cannabis. Qualified patients must possess a physician's recommendation to use cannabis and must register with the state Department of Health. So far, eleven states (Alaska, California, Colorado, Hawaii, Maine, Montana, Nevada, Oregon, Rhode Island, Vermont, and Washington) have enacted similar laws. (Source: NORML of 8 June 2006)

UK — Dronabinol

Dronabinol capsules 2.5 mg, 5 mg and 10 mg are now available in the UK from the Specials Laboratory Newcastle. In a joint venture between STI Pharmaceuticals Ltd and THC Pharm Frankfurt, manufacture of various cannabinoid preparations have been transferred to the Specials Laboratory to ease supply difficulties experienced by UK clinicians and researchers wishing to investigate cannabinoids. Interested researchers and clinicians should contact Fiona Cruickshank (FionaC@specialslab.co.uk). (Source: Personal communication by Andrew Davies of STI Pharmaceuticals)

USA — House of Representatives

In the coming months, the House of Representatives will vote on an amendment that would end the federal government's attacks on patients in states with medical cannabis laws. The Hinchey-Rohrabacher medical marijuana amendment of 2005 said: "None of the funds made available in this Act to the Department of Justice may be used to prevent the States of Alaska, California, Colorado, Hawaii, Maine, Montana, Nevada, Oregon, Vermont, or Washington from implementing State laws authorizing the use of medical marijuana in those States." It is expected that the language of the amendment in 2006 will be the same - with the addition of Rhode Island. (Source: Marijuana Policy Project)

Science — Psychosis

In an Australian study reasons for cannabis use by psychotic patients were investigated by interviews with 49 people with psychotic disorders. It was found that boredom, social motives, improving sleep, anxiety and agitation and symptoms associated with negative psychotic symptoms or depression were the most important motivators of cannabis use, while positive symptoms had no influence. Symptoms of psychosis may be classified as positive (for instance delusions, hallucinatory behaviour and grandiosity) or negative (for instance flat affect, and emotional or social withdrawal). (Source: Schofield D, et al. Aust N Z J Psychiatry 2006;40(6):570-4)

Science — Water-soluble cannabinoids

Scientists of the Virginia Commonwealth University in the USA synthesized new cannabinoids that are soluble in water and therefore may be injected. (Source: Martin BR, et al. J Pharmacol Exp Ther. 2006 Jun 6; [electronic publication ahead of print])