Recent data on cannabinoids and their pharmacological implications in neuropathic pain.

Abstract

“Natural cannabinoids have been used for centuries for their psychotropic properties, but their possible therapeutic implications in analgesia have been recently documented. The present review intended to make an analysis of the neuroanatomy and physiology of the cannabinoid system (receptors, functions, agents acting on these receptors) and of its implications in neuropathic pain. There were also described the complex phenomena implicated in the generation and maintenance of neuropathic pain, by high lightening the implications of endogenous cannabinoids in this complex of painful conditions. The pharmacological analgesia test proves of cannabinoid implication in neuropathic pain was sustained by many studies presented in this paper. Therapeutic approaches using natural and synthetic cannabinoid receptor agonists were reviewed. Therapeutic perspectives in neuropathic pain might involve the development of new agents that influence the cannabinoid system. Thus, peripheral acting cannabinoid 1 receptors agonists, selective cannabinoid 2 receptor agonists and also modulators of endocannabinoids metabolism might be a way to success in the treatment of this complex entity called neuropathic pain.”

http://www.ncbi.nlm.nih.gov/pubmed/20108515

Cannabinoids as pharmacotherapies for neuropathic pain: from the bench to the bedside.

“Neuropathic pain is a debilitating form of chronic pain resulting from nerve injury, disease states, or toxic insults. Neuropathic pain is often refractory to conventional pharmacotherapies, necessitating validation of novel analgesics. Cannabinoids, drugs that share the same target as Delta(9)-tetrahydrocannabinol (Delta(9)-THC), the psychoactive ingredient in cannabis, have the potential to address this unmet need…

In humans, effects of smoked marijuana, synthetic Delta(9)-THC analogs (e.g., Marinol, Cesamet) and medicinal cannabis preparations containing both Delta(9)-THC and cannabidiol (e.g., Sativex, Cannador) in neuropathic pain states are reviewed. Clinical studies largely affirm that neuropathic pain patients derive benefits from cannabinoid treatment…

Evidence for the use of Cannabis sativa as a treatment for pain can be traced back to the beginnings of recorded history…

 http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2755639/

Marijuana Eases Neuropathic Pain

“Smoking marijuana modestly reduced pain and other symptoms of chronic neuropathic pain, results of a small randomized, placebo-controlled trial showed.

These results are important in light of the fact that patients who hear about pain relief from ongoing publicity about medical marijuana have had only a “trickle” of evidence to prove it, explained Henry J. McQuay, DM, of Oxford University, in an accompanying editorial.

This study does offer hope since few drugs have proven effective in these patients, commented Steven P. Cohen, MD, who as director of pain research at Walter Reed Army Medical Center in Washington, D.C., sees chronic pain in most of his patients with major war injuries.”

Marijuana smoking appeared well tolerated…

Patients rarely got high on the single hit they took through a pipe three times a day as part of the study, Ware’s group noted.”

Read more: http://www.medpagetoday.com/Neurology/PainManagement/21939

Smoking Marijuana Eases Chronic Neuropathic Pain.

“Smoking cannabis reduces chronic neuropathic pain and also improves sleep, according to new research published today in the Canadian Medical Association Journal.

A single inhalation of 25 mg of 9.4% tetrahydrocannabinol herbal cannabis 3 times a day for 5 days was sufficient to achieve these outcomes, lead study author Mark A. Ware, MBBS, from McGill University Health Center, Montreal, Canada, told Medscape Medical News in an interview.

“Patients have been reporting that cannabis helps control their pain, and they have been saying so for a long time,” Dr. Ware said. “At the time that we had secured the funding and began the trial, there had been no clinical trials that had established this or investigated it.”

In addition, a large body of scientific knowledge is emerging abound the role of cannabinoid receptors and cannabinoid ligands in the human body, providing a potential scientific explanation as to why cannabinoids would be analgesic, he added. “So the 2 main supports came together, and in Canada at the time, there was an environment where we were able to secure funding sufficient for studies of this.”

Posttraumatic and Postsurgical Neuropathy

The study included 21 individuals older than 18 years (mean age, 45.4 years) with posttraumatic or postsurgical neuropathic pain lasting for at least 3 months. They were randomly assigned to receive cannabis at 4 potencies — 0%, 2.5%, 6%, and 9.4% tetrahydrocannabinol — during 4 periods in a crossover design. Each period lasted 14 days and began with 5 days of cannabis use followed by a 9-day washout period.

The cannabis doses were delivered in a single smoked inhalation using a titanium pipe. Patients self-administered the first dose of each period under supervision and were instructed to inhale for 5 seconds while the cannabis was lit, hold the smoke in their lungs for 10 seconds, and then exhale. They self-administered the remaining doses for each period at home.

The participants were allowed to continue their routine medications, and the use of acetaminophen as breakthrough analgesia was also permitted.

Pain intensity was measured using an 11-item numeric rating scale that used “no pain” and “worst pain possible” as anchors.

The study found that the higher dose of cannabis was the most efficient in reducing pain. The average daily pain intensity was 5.4 with the 9.4% tetrahydrocannabinol cannabis dose compared with 6.1 with the 0% or placebo dose (95% confidence interval, 0.02 – 1.4; P = .023).

In addition, participants reported significantly more drowsiness and reported getting to sleep more easily, faster, and with fewer periods of wakefulness when taking the 9.4% dose than when taking the 0% dose ( P < .05). The higher dose also improved anxiety and depression compared with the placebo dose.

Blind Held; Studies Feasible

“It was feared that participants would know right away if they were smoking cannabis because of the acute psychoactive effects of the drug, but our results do not support this,” Dr. Ware noted. “They do show that short-term placebo-controlled trials of smoked cannabis are feasible.”

He would like his study to act as a stimulus for other studies on cannabis and pain relief.

“Studies of this kind can be done. Ours was difficult to do because it was the first time we had done anything like this. We were breaking new ground with regard to regulations and so on, but it is possible. Having done it once, it’s not as difficult to do it again. So our results raise the possibility of extending the study for a longer duration, or being able to look at safety issues, and so on. It is possible to do a scientific trial with this compound. Your political views shouldn’t matter. This is just good science,” Dr. Ware said.

In a related commentary, Henry J. McQuay, DM, from Balliol College, Oxford, United Kingdom, writes that the study authors should be congratulated for tackling the question of whether cannabis helps in neuropathic pain, “particularly given that the regulatory hurdles for their trial must have been a nightmare.”

He concludes that the study “adds to the trickle of evidence that cannabis may help some of the patients who are struggling at present.””

http://www.medscape.com/viewarticle/727702

Research: Marijuana can treat chronic pain – ABC

“SACRAMENTO, CA (KGO) — A program commissioned more than a decade ago by the state Legislature to look into the therapeutic value of medicinal marijuana is expected to release a report on its findings today, a spokeswoman for state Sen. Mark Leno said.

A UC medical marijuana research panel today released the results of a ten year clinical study and according to its report, pot can effectively treat chronic pain.

Volunteers with multiple sclerosis and spinal cord injuries were randomly treated with marijuana or a placebo. Patients given cannabis reported fewer multiple sclerosis muscle spasms, and less spinal injury pain.

In another study, the panel found that pot effectively also treats migraines.

But researchers used marijuana grown by the federal government, not the kinds available to California medical marijuana users.

Medical marijuana has been legal under California law since voters approved Proposition 215, also known as the Compassionate Use Act, in 1996.

The state Legislature clarified in 2004 that the Compassionate Use Act allows qualified patients and their primary caregivers to cultivate marijuana for medicinal use.

Medical marijuana remains illegal under federal law, though, leaving patients and providers open to prosecution in federal court.”

http://abclocal.go.com/kgo/story?section=news/state&id=7283032

Marijuana Relieves HIV Nerve Pain

“Smoking marijuana effectively relieves chronic HIV-associated nerve pain, including aching, painful numbness, and burning, according to a study published in the February 13, 2007, issue of Neurology®, the scientific journal of the American Academy of Neurology.

For the study, 50 people with HIV-associated sensory neuropathy, the most common HIV nerve disorder, were admitted to a California hospital and randomly assigned to smoke either marijuana or identical placebo cigarettes three times a day for five days.

The study found people who smoked marijuana reduced their daily nerve pain by 34 percent compared to 17 percent in the placebo group.

“Smoking marijuana was well tolerated and effectively relieved chronic nerve pain from HIV-associated sensory neuropathy,” said study author Donald Abrams, MD, with San Francisco General Hospital in San Francisco, California. “Our findings show the amount of relief from smoking marijuana is comparable to relief provided by oral drugs currently used for chronic nerve pain.”

Abrams says while some HIV patients with chronic nerve pain are able to take anticonvulsant drugs, such as lamotrigine and gabapentin, to ease pain, some patients don’t respond well to these drugs. He says that’s why there’s heightened interest in evaluating marijuana as a treatment for chronic nerve pain.

The study also found the first marijuana cigarette reduced chronic pain by an average of 72 percent versus 15 percent with placebo. And more than half of the people who smoked marijuana reported more than a 30-percent reduction in pain compared to 24 percent in the placebo group.

Participants in the study reported no serious side effects.

Researchers say similar results were reported in two recent placebo-controlled studies of marijuana-related therapies for nerve pain associated with multiple sclerosis.

The study was supported by the University of California Center for Medicinal Cannabis Research and conducted at the National Institutes of Health-funded General Clinical Research Center at San Francisco General Hospital.”

http://www.medicalnewstoday.com/releases/63333.php

Marijuana component could ease pain from chemotherapy drugs

“A chemical component of the marijuana plant could prevent the onset of pain associated with drugs used in chemo therapy, particularly in breast cancer patients, according to researchers at Temple University’s School of Pharmacy.

“We found that cannabidiol completely prevented the onset of the neuropathic, or caused by the chemo drug Paclitaxel, which is used to treat ,” said Ward, who is also a research associate professor in Temple’s Center for Substance Abuse Research.

Ward said that one of cannabidiol’s major benefits is that, unlike other chemicals found in marijuana such as THC, it does not produce psycho-active effects such as euphoria, increased appetite or cognitive deficits. “Cannabidiol has the therapeutic qualities of marijuana but not the side effects,” she said.”

Read more: http://medicalxpress.com/news/2011-10-marijuana-component-ease-pain-chemotherapy.html

Study: Smoking Pot May Ease Chronic Pain

By Amanda Gardner
smoking pot chronic pain 200x150 Study: Smoking Pot May Ease Chronic Pain

 “People with chronic pain who aren’t getting enough relief from medications may be able to ease their pain by smoking small amounts of marijuana, a new study suggests.

Marijuana also helps pain patients fall asleep more easily and sleep more soundly, according to the report, one of the first real-world studies to look at the medicinal use of smoked marijuana. Most previous research has used extracts of tetrahydrocannabinol (THC), the active ingredient in the cannabis plant.

“This is the first time anyone has done a trial of smoked cannabis on an outpatient basis,” says the lead researcher, Mark Ware, MBBS, the director of clinical research at McGill University’s Alan Edwards Centre for Research on Pain, in Montreal.

The study included 21 adults with nervous-system (neuropathic) pain stemming from surgery, accidents, or other trauma. Fourteen of the participants were on short-term disability or permanently disabled. All of them had tried marijuana before, but none were current or habitual smokers.

“They were not experienced marijuana users,” Ware says. “They came because they had severe pain that was not responding to any conventional treatment.”

Each patient in the study smoked four different strengths of marijuana over a period of 56 days. The THC potency ranged from 9.4%—the strongest dose the researchers could obtain legally—to 0%, a “placebo” pot that looked and tasted like the real thing but was stripped of THC. (By comparison, the
strongest marijuana available on the street has a THC potency of about 15%, Ware estimates.)

The participants—who weren’t told which strength they were getting—were instructed to smoke a thimbleful (25 milligrams) from a small pipe three times a day for five days. After a nine-day break, they switched to a different potency.

The highest dose of THC yielded the best results. It lessened pain and improved sleep more effectively than the placebo and the two medium-strength doses (which produced no measurable relief), and it also reduced anxiety and depression. The effects lasted for about 90 minutes to two hours, according to the study.”

Read more: http://news.health.com/2010/08/30/marijuana-chronic-pain/

Cannabis spray found to help relieve cancer pain

“Cancer patients who used a cannabis mouthspray had their level of pain reduced by 30%, a study has shown.

The cannabis-based spray, like a mouth freshener, was used on 177 patients by researchers from Edinburgh University.

They found it reduced pain levels by 30% in a group of cancer patients, all in the Edinburgh area, who had not been helped by morphine or other medicines.

The spray was developed so that it did not affect the mental state of patients in the way that using cannabis would.

Site of pain

They said the spray worked by activating molecules in the body called cannabinoid receptors which can stop nerve signals being sent to the brain from the site of pain.

Professor Marie Fallon, of the Edinburgh Cancer Research Centre at Edinburgh University, said: “These early results are very promising and demonstrate that cannabis-based medicines may deliver effective treatment for people with severe pain.

“Prescription of these drugs can be very useful in combating debilitating pain, but it is important to understand the difference between their medical and recreational use.””

http://www.plymouthwired.co.uk/news.php/2777-Cannabis-spray-found-to-help-relieve-cancer-pain

Cannabis spray blunts pain

 Erica Klarreich

“Early trials suggest cannabis spritz may give relief to chronic pain sufferers.”

Cannabis: 5,000 years of medicinal use.Cannabis: 5,000 years of medicinal use.© Photodisc

“A spray that delivers the active ingredient of cannabis under the tongue may ease chronic pain, preliminary clinical trials suggest.

Of the 23 patients who participated in the controlled study, only a few failed to respond to the spray, William Nortcutt of James Paget Hospital in Gorleston, UK told the British Association for the Advancement of Science’s Annual Festival of Science on Monday. Seventeen have gone on to use the drug to treat their pain in the long term, he said.

“Some of the patients said it made a huge difference; others just said it lets them sleep,” Nortcutt said. “But when you’re in chronic pain, being able to sleep is one of the most important things.”

Earlier clinical trials have also shown the pain-relieving benefits of cannabis. But researchers have struggled to find a good way to deliver the drug, says Roger Pertwee, a neuropharmacologist and cannabis expert at the University of Aberdeen, UK.

“The study with a spray is very interesting,” he says. “The past clinical trials have been with pills, but absorption by swallowing is very unreliable.”

About half of the trial’s participants had multiple sclerosis; the rest suffered chronic pain from severe nerve damage and spinal-cord injuries. Although a few of the multiple sclerosis patients had been using cannabis to treat pain before the trials, most participants had seldom or never used it.

The most common side-effect appeared to be dry mouth, Nortcutt reports. Several patients experienced panic or a high during tests to find appropriate dosages. Most preferred a drug in which the active substance, tetrahydrocannabinol (THC), was mixed with another, less psychoactive ingredient of cannabis. Previous clinical studies have involved only pure THC, Pertwee says.

The research comes as many groups are pushing for cannabis to be legalized for therapeutic use in the United Kingdom. If cannabis were to be made legal, Nortcutt says, the path to approval might be much faster than for typical drugs, which take an average of six years.

“There is a huge amount of anecdotal evidence that would help scientists,” Nortcutt told the Glasgow meeting. “We have to recognize that cannabis has been used for 5,000 years.” But much more work is needed to understand how cannabis might be exploited as a pain treatment, Nortcutt warned. “I wouldn’t call for it to be prescribed now.””

http://www.nature.com/news/1998/010906/full/news010906-7.html