Cannabinoids in cancer pain - International Association for ...

cannabis.med.org

Cannabinoids in cancer pain - International Association for ...

Cannabinoids 2010;5(1):1-3Article of the MonthCannabinoids in cancer painFranjo Grotenhermennova-Institut, Chemiepark Knapsack, Industriestraße, D-50354 Hürth, GermanyAbstractThis article of the month presents results of a clinical study conducted in the UK and Romania,which evaluated the efficacy of a THC:CBD cannabis extract (Sativex®) and a THC cannabis extractin the treatment of 177 patients with cancer pain, who experienced inadequate pain reductiondespite intake of opioids [Johnson et al. J Pain Symptom Manage, 2010, in press]. Sativex resultedin a significant improvement of mean pain scores on a primary outcome measure, a NumericalRating Scale (NRS) from 0 to 10 compared to placebo (improvement of -1.37 versus -0.69), whilethe THC extract caused a non-significant improvement (-1.01). Conversely, there was a significantimprovement in total pain according to the Brief Pain Inventory-Short Form in the THC-groupcompared to placebo but a non-significant improvement following Sativex.Keywords: cannabis, THC, cannabidiol, chronic pain, cancer, clinical trial.This article can be downloaded, printed and distributed freely for any non-commercial purposes, provided the original work is properlycited (see copyright info below). Available online at www.cannabis-med.orgAuthor's address: Franjo Grotenhermen, franjo.grotenhermen@nova-institut.deBackground InformationLess than 10 years ago there were only very limitedclinical data available on the possible benefits of cannabinoidsin chronic pain [1]. Several studies evaluatedtheir analgesic potential in acute pain states, where theyoften even increased pain. In sum, clinical data did notallow any conclusions on the role of cannabis and cannabinoidsin chronic pain conditions at that time andsuggested only a limited potential of cannabinoids inthe treatment of pain, contradicting personal experiencesof patients, who successfully self-medicated withcannabis.This picture changed within recent years with a numberof clinical studies with different cannabinoid preparations(dronabinol, nabilone, cannabis extracts, inhaledcannabis) demonstrating analgesic effects in differentchronic pain conditions [5]. There is evidence thatendocannabinoids produced in the spinal cord canenhance pain by dampening the activity of inhibitoryneurons [2]. This pain-promoting action of endocannabinoidswanes during the development of chronicinflammatory or neuropathic pain. This may explainthe differences of cannabinoid effects in acute andchronic pain.Experiences of pain patients were usually made withcannabis preparations high in THC (dronabinol) concentrationand very low in other cannabinoids sincecannabis strains available on the illegal market bred forhigh dronabinol mostly contain only negligibleamounts of other cannabinoids [3]. Thus, cannabidiol(CBD) was introduced into therapy only in recent yearsby pharmaceutical companies and scientific institutes,albeit some patients may have unwittingly experiencedthe effects of CBD mainly when using cannabis resin(hashish), which more often may contain high CBDconcentrations than cannabis herb (marijuana).Currently two whole-plant cannabis extracts (Cannador®and Sativex®) are under investigation or inclinical use. Cannador (Institute for Clinical Research,Germany) contains dronabinol and other cannabinoids(mostly CBD) in a ratio of about 2:1 and is administeredas a capsule (oral use). Sativex (GW Pharmaceuticals,UK) contains dronabinol and cannabidiol in aratio of about 1:1 and is administered as a spray intothe mouth (oromucosal use). The pharmacokineticprofile of THC in Sativex is similar to THC after oraluse, suggesting that most of the extract is swallowedand absorbed by the gastrointestinal tract [4].Summary of the original articleJohnson et al. (2010) compared the efficacy of Sativexand a THC cannabis plant extract with placebo in re-© International Association for Cannabinoid Medicines 1


GrotenhermenRelated Pain. J Pain Symptom Manage, 2010 inpress.Cannabinoids Vol 5, No 1 January 23, 2010 3

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