Cannabinoids in pain and palliative care medicine – hope or dope?

Plant material of Indian hemp, Cannabis sativa, was used throughout millennia for the production of fibres and for recreational and medical purposes. Scientific research in the field of cannabinoids has led to the discovery of a new lipid signalling system in humans and animals, the endogenous cannabinoid system with specific receptors and physiological ligands. The endocannabinoid system now appears as a relevant modulator of physiological functions not only in the central nervous system, but also in the endocrine network, the immune system, the gastrointestinal tract and the reproductive system. It is involved in numerous biological processes including reward-reinforcing effects, memory, energy metabolism and pain processing. Promising targets for medical use of cannabinoids include the alleviation of nausea and vomiting, the relief of anorexia and weight loss in HIV and cancer patients, the easing of different types of pain and muscle spasticity. But cannabinoid effects in clinical trials on pain, weight loss, nausea and vomiting were often only modest and hampered by the psychotropic side effects of the available compounds. Therefore, cannabinoids are still not first line therapeutics for these symptoms, but they are nevertheless a useful adjuvant treatment option for palliative care patients by alleviating more than one symptom, improving the quality of life in chronic pain and cancer patients.