Give me dope for hope
Workshop by Christoph Ritter
Whether drugs, such as cannabis and cannabinoids (c.& c.), may be potential analgesics to treat patients suffering from chronic pain was the main question we tried answer during workshop 3 łgive me dope for hope˛ led by Prof. Dr. C. Ritter.
By splitting up into three groups we faced the problem from a pharmacological as well as clinical point of view, whereas the third group dealt with adverse side effects c./c. may cause.
Two cannabis receptors (CB1 and CB2) have been identified in the human body. Increased levels of CB1 receptors have been found in certain areas of the central and peripheral nervous system. CB2 receptors are located peripherally and closely linked with cells in the immune system. The determination of the specific location the receptors do have in the body as well as a sufficient understanding of their physiological role and their chemical structure may on the one hand account for the effects of c.& c. on memory, emotion, cognition and movement, but on the other hand explain the lack of respiratory depression associated with these compounds. However, it is estimated that the damage to the bronchial epithelium (absorption of carbon monoxide and the deposit of tar) of 3-4 cannabis cigarettes daily are equivalent to 20 tobacco cigarettes per day.
Another group found out that the usage of synthetically produced Delta-9-tetrahydrocannabiol (THC) does not cause any relief in patients suffering from chronic non-malignant pain, however, less additional morphine for breakthrough pain was needed, while the patient was taking THC than while taking placebo. THC is also used in the US in the treatment of nausea and vomiting induced by chemotherapy. Since the number of published human trials on the use of c.& c. in chronic pain is limited and the results are equivocal there is no evidence that these natural as well as synthetic substances may serve as efficient and save analgesics in the treatment of for instance spasm of multiple sclerosis and resistant neuropathic pain.
Cannabis is used recreationally because of the euphoria that it produces. The adverse psychological effects (including psychomotor, feeling of loss of control, mental clouding, impaired memory, depersonalisation, paranoia, hallucinations and depression), which are partly due to functional brain changes, may limit therapeutic use. Other adverse physical effects include dry mouth, blurred vision, palpitation, tachycardia and hypotension. The effects on fertility have not been entirely studied and there is no evidence of teratogenicity either. Tolerance to many pharmacological effects (incl. mood changes, heartrate, blood pressure and psychomotor performances) can be developed within weeks with repeated dosage, although not at the same rate or degree for different effects. This procedure can be helpful to eliminate unwanted effects, but becomes disadvantageous as soon as desired effects are involved.
Finally we came to the conclusion that the variety of potential adverse side effects is too significant to support a general introduction of c.& c. as analgesics in clinical practice. In certain severe cases of chronic pain they may be used , but only, if conventional analgesics or placebo have failed. There is still a lot of research to be done in future times until the time the slogan "give me dope for hope" will turn into medical reality.
|
