Marijuana Relieves Chronic Pain, Research Shows – WebMD

“Three puffs a day of cannabis, better known as marijuana, helps people with chronic nerve pain due to injury or surgery feel less pain and sleep better, a Canadian team has found.

”It’s been known anecdotally,” says researcher Mark Ware, MD, assistant professor of anesthesia and family medicine at McGill University in Montreal. “About 10% to 15% of patients attending a chronic pain clinic use cannabis as part of their pain [control] strategy,” he tells WebMD.

But Ware’s study is more scientific — a clinical trial in which his team compared placebo with three different doses of cannabis. The research is published in CMAJ, the Canadian Medical Association Journal.

The new study ”adds to the trickle of evidence that cannabis may help some of the patients who are struggling [with pain] at present,” Henry McQuay, DM, an emeritus fellow at Balliol College, Oxford University, England, writes in a commentary accompanying the study…” More: http://www.webmd.com/pain-management/news/20100830/marijuana-relieves-chronic-pain-research-show

“Smoked cannabis for chronic neuropathic pain: a randomized controlled trial… A single inhalation of 25 mg of 9.4% tetrahydrocannabinol herbal cannabis three times daily for five days reduced the intensity ofpain, improved sleep and was well tolerated.”  http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2950205/

For many patients, cannabis may offer the best medicinal pain relief yet discovered

by: Raw Michelle

“(NaturalNews) By the beginning of the 1980s, after a four decade long lockdown, a re-interest in cannabis arose in the scientific community. In 1982, the American Institute of Medicinepublished an intriguing report entitled “Marijuana and Health”. The report was a collection of tentative exploratory research and case studies of the use of cannabis as a medicine.

The reappearance of a powerful plant in human pharmacopeia

The studies provided a glimpse of something that intrigued health care researchers. While the plant’s effects were entirely congruent with the goal of healing, the methodology used by the plant’s chemicals was very different from those employed by typical pharmaceuticals. To developers, cannabis suddenly represented a precedent for a whole new type of medicine. With over 88 pharmacologically active substances, cannabis introduced hundreds of new compounds to the medical world. The institute’s report concluded that further research into cannabis’ potential would be of great value to the field.

However, further research was very limited, stifled by cannabis’ legal status and social stigma. The legal status forces researchers to expend an overwhelming amount of time and effort to get permission to conduct the studies. The social stigma causes institutes to be less likely to receive funding for the projects, and that researchers are sacrificing their reputation in the professional world. That also means most of the studies conducted are federally funded. Unfortunately, in addition, successful researchers will still have to face a further publication bias, as journals also risk their reputations and status when publishing cannabis related research. It is ironic that even within a scientific community, researchers are punished for being unbiased. As a result, outlets that focus solely on cannabis related research have arisen. Internet publications have opened a wide market for research that would have previously been buried.

Where opiates don’t quite cut it

Of the studies that have been conducted, most have focused on marijuana as a treatment for neuropathic pain, one of the earliest treatments for which physicians saw potential. Neuropathic pain results from nerve damage in which the cells experience difficulty communicating. This can happen from traumas like surgery, where nerve connections are severed, but continue trying to communicate news of the damage to the next cell over. Similarly, when new nerve cells are formed but not yet hooked into the neural highway, they sputter and spark, trying to achieve connection. The sensation can be very painful. Neuropathic pain is very common symptom of cancer. Tumour growth can crush nerve trunks as it bullies its way to more territory.

Sometimes just talking about it helps

Early studies demonstrate that cannabis is hugely effective in treating neuropathic pain. The cannabinoids allow nerve cells to reverse the communication path. Cells sending trauma notifications to the main trunk would normally continue doing so until the stimuli was resolved. From a practical standpoint, it is difficult to eliminate pain the moment it is recognised, but from a human level, once the person is cognizant of the problem, there is no benefit to remaining in pain. Cannabis simply tells the alarmed cell that authorities have been notified and that the problem will be resolved shortly. It doesn’t, as is popularly believed, relieve pain by making cells “stoned” or unfocused so as to disrupt communication.

The few studies have been conducted have returned agreeing with the American Medical Institute’s findings and recommendations. After only preliminary examination, cannabis presents itself as a powerful tool. More in-depth research is likely to further displace today’s most relied-upon pharmaceuticals.”

 
 
 

The Endocannabinoid System and Pain

Gallery

“Cannabis has been used for more than twelve thousand years and for many different purposes (i.e. fiber, medicinal, recreational). However, the endocannabinoid signaling system has only recently been the focus of medical research and considered a potential therapeutic target. Endocannabinoids … Continue reading

Antinociceptive effects induced through the stimulation of spinal cannabinoid type 2 receptors in chronically inflamed mice.

“The stimulation of spinal cannabinoid type 2 (CB(2)) receptors is a suitable strategy for the alleviation of experimental pain symptoms. Several reports have described the up-regulation of spinal cannabinoid CB(2) receptors in neuropathic settings together with the analgesic effects derived from their activation. Besides, we have recently reported in two murine bone cancer models that the intrathecal administration of cannabinoid CB(2) receptor agonists completely abolishes hyperalgesia and allodynia, whereas spinal cannabinoid CB(2) receptor expression remains unaltered. The present experiments were designed to measure the expression of spinal cannabinoid CB(2) receptors as well as the analgesic efficacy derived from their stimulation in mice chronically inflamed by the intraplantar injection of complete Freund’s adjuvant 1 week before…

 These results demonstrate that effective analgesia can be achieved in chronic inflammatory settings through the stimulation of spinal cannabinoid CB(2) receptors even if this receptor population is not up-regulated.”

http://www.ncbi.nlm.nih.gov/pubmed/21771590

Central and peripheral sites of action for CB₂ receptor mediated analgesic activity in chronic inflammatory and neuropathic pain models in rats.

“Although the analgesic properties of non-selective cannabinoid receptor agonists have been known for many years, there is now an increasing body of evidence to support the potential utility of selective cannabinoid CB2 receptor agonists for the treatment of pain…

Cannabinoid CB2 receptor activation by selective agonists has been shown to produce analgesic effects in preclinical models of inflammatory and neuropathic pain. However, mechanisms underlying CB2-mediated analgesic effects remain largely unknown. The present study was conducted to elucidate the CB2 receptor expression in ‘pain relevant’ tissues and the potential sites of action of CB2 agonism in rats.

CONCLUSIONS AND IMPLICATIONS

These results demonstrate that both DRG and spinal cord are important sites contributing to CB2 receptor-mediated analgesia and that the changes in CB2 receptor expression play a crucial role for the sites of action in regulating pain perception.”

http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3031063/

CB2 receptor-mediated antihyperalgesia: possible direct involvement of neural mechanisms.

 “These results confirm that CB2 is present in the central nervous system and suggest that CB2 agonists may elicit their analgesic effect by acting not only at non-neuronal peripheral sites but also at neural level, making CB2 an attractive target for chronic pain treatment.”

http://www.ncbi.nlm.nih.gov/pubmed/16553616

The cannabinoid system and pain: towards new drugs?

Abstract

“The various components of the endocannabinoid system were discovered in the last twenty years. The cannabinoid system has attracted pharmacologists interest for its potential as therapeutic targets for several diseases ranging from obesity to Parkinson’s disease and from multiple sclerosis to pain. Research initially focused on cannabinoid receptor 1 (CB1), but, due to psychotropic side effects related to its activation, the attempts to develop an agonist drug for this receptor has been so far unsuccessful. Recently the possibility to target CB2 has emerged as an alternative for the treatment of pain. The main advantage of targeting CB2 resides in the possibility to elicit the analgesic effect without the psychotropic side effects. Evidence of the analgesic effect of CB2 selective agonists has been obtained in various models of both inflammatory and neuropathic chronic pain. To explain the mechanism at the basis of this analgesic effect different hypotheses have been proposed: effect on inflammatory cells, reduction of basal NGF tone, induction of beta-endorphin release from keratinocytes, direct action on nociceptors. Evidence in support of this last hypothesis comes from down regulation of capsaicin-induced CGRP release in spinal cord slices and Dorsal Root Ganglia (DRG) neurons in culture after treatment with CB2 selective agonists. CB2 agonists are probably acting through several mechanisms and thus CB2 represents an interesting and promising target in the chronic pain field. Further clarification of the mechanisms at the basis of CB2 analgesic effect would surely be an intriguing and stimulating area of research for the years to come.”

http://www.ncbi.nlm.nih.gov/pubmed/19358815

Cannabinoids and pain.

Abstract

“Recent advances have dramatically increased our understanding of cannabinoid pharmacology: the psychoactive constituents of Cannabis sativa have been isolated, synthetic cannabinoids described and an endocannabinoid system identified, together with its component receptors, ligands and their biochemistry. Strong laboratory evidence now underwrites anecdotal claims of cannabinoid analgesia in inflammatory and neuropathic pain. Sites of analgesic action have been identified in brain, spinal cord and the periphery, with the latter two presenting attractive targets for divorcing the analgesic and psychotrophic effects of cannabinoids. Clinical trials are now required, but are hindered by a paucity of cannabinoids of suitable bioavailability and therapeutic ratio.”

http://www.ncbi.nlm.nih.gov/pubmed/11575713

[The pharmacology of cannabinoid derivatives: are there applications to treatment of pain?].

“OBJECTIVE:

To present the cannabinoid system together with recent findings on the pharmacology of these compounds in the treatment of pain.

DATA SOURCES:

Search through Medline database of articles published in French and English since 1966. Also use of other publications such as books on cannabis.

DATA SYNTHESIS:

Recent advances have dramatically increased our understanding of cannabinoid pharmacology. The psychoactive constituents of Cannabis sativa have been isolated, synthetic cannabinoids described and an endocannabinoid system identified, together with its component receptors and ligands. Strong laboratory evidence now underwrites anecdotal claims of cannabinoid analgesia in inflammatory and neuropathic pain. Sites of analgesic action have been identified in brain, spinal cord and the periphery, with the latter two presenting attractive targets for divorcing the analgesic and psychotrophic effects of cannabinoids. Clinical trials are now required, but are hindered by a paucity of cannabinoids of suitable bioavailability and therapeutic ratio.

CONCLUSION:

The cannabinoid system is a major target in the treatment of pain and its therapeutic potential should be assessed in the near future by the performance of new clinical trials.”

http://www.ncbi.nlm.nih.gov/pubmed/12134594

Cannabinoid analgesia as a potential new therapeutic option in the treatment of chronic pain.

Abstract

“OBJECTIVE:

To review the literature concerning the physiology of the endocannabinoid system, current drug development of cannabinoid agonists, and current clinical research on the use of cannabinoid agonists for analgesia.

DATA SOURCES:

Articles were identified through a search of MEDLINE (1966-August 2005) using the key words cannabis, cannabinoid, cannabi*, cannabidiol, nabilone, THC, pain, and analgesia. No search limits were included. Additional references were located through review of the bibliographies of the articles identified.

STUDY SELECTION AND DATA EXTRACTION:

Studies of cannabinoid agonists for treatment of pain were selected and were not limited by pain type or etiology. Studies or reviews using animal models of pain were also included. Articles that related to the physiology and pharmacology of the endocannabinoid system were evaluated.

DATA SYNTHESIS:

The discovery of cannabinoid receptors and endogenous ligands for these receptors has led to increased drug development of cannabinoid agonists. New cannabimimetic agents have been associated with fewer systemic adverse effects than delta-9-tetrahydrocannabinol, including recent development of cannabis medicinal extracts for sublingual use (approved in Canada), and have had promising results for analgesia in initial human trials. Several synthetic cannabinoids have also been studied in humans, including 2 cannabinoid agonists available on the international market.

CONCLUSIONS:

Cannabinoids provide a potential approach to pain management with a novel therapeutic target and mechanism. Chronic pain often requires a polypharmaceutical approach to management, and cannabinoids are a potential addition to the arsenal of treatment options.”

http://www.ncbi.nlm.nih.gov/pubmed/16449552