Analgesic Efficacy of Smoked Cannabis

INVESTIGATOR: Mark Wallace, M.D.

STUDY LOCATION: University of California, San Diego

PROJECT TITLE: Analgesic Efficacy of Smoked Cannabis

PROJECT TYPE: Clinical Study

STATUS: COMPLETE

RESULTS:

In a randomized, double-blinded, placebo controlled, crossover trial in fifteen healthy volunteers, we evaluated the effects of low, medium, and high dose smoked cannabis (respectively 2%, 4%, and 8% 9-delta-tetrahydrocannibinol by weight) on pain and cutaneous hyperalgesia induced by intradermal capsaicin. Capsaicin was injected into opposite forearms 5 and 45 minutes after drug exposure and pain, hyperalgesia, tetrahydrocannibinol plasma levels, and side effects were assessed.

Five minutes after cannabis exposure, there was no effect on capsaicin-induced pain at any dose. By 45 minutes after cannabis exposure, however, there was a significant decrease in capsaicin-induced pain with the medium dose and a significant increase in capsaicin-induced pain with the high dose. There was no effect seen with the low dose nor was there an effect on the area of hyperalgesia at any dose. Significant negative correlations between pain perception and plasma delta-9-tetrahydrocannibinol levels were found after adjusting for the overall dose effects. There was no significant difference in performance on the neuropsychological tests.

This study suggests that there is a window of modest analgesia for smoked cannabis with lower doses decreasing pain and higher doses increasing pain.

The full results of this study were published in the journal Anesthesiology.

ABSTRACT:

By every criteria (deterioration in quality of life; loss of work days, and therapy directed dollars) pain is appreciated to be a major medical problem. Recent findings in the molecular biology and the pharmacology of pain transmission have shed light on mechanisms of nociceptive processing and the activity of a variety of "novel therapeutic" modalities that include the cannabinoids. Although the pre-clinical literature suggests that the cannabinoids produce antinociception and anti-hyperalgesic effects, the efficacy of the cannabinoids in the human pain state is unclear. As an experimental variable, clinical pain is a multidimensional phenomenon with few objective physical correlates. Many other factors such as emotional status and coping skills, make "pain" difficult to study in the clinical setting. An important development has been the implementation of well-controlled experimental pain models to investigate the sensory components of pain processing and to use these models in the assessment of analgesic efficacy in normal volunteers. To the degree that human experimental pain models can predict analgesic efficacy of novel agents, the role of mechanisms defined in preclinical studies can be translated to the human experience under well-controlled conditions. Human experimental pain has been used to test a wide range of currently available analgesics. Knowing the effect of these agents on human experimental pain, I now wish to study the effects of cannabis on human experimental pain and how this compares to commonly used analgesics.

PUBLICATIONS:

Type:

Title:

Journal Article Wallace M, Schulteis G, Atkinson JH, Wolfson T, Lazzaretto D, Bentley H, Gouaux B, Abramson I (November 2007) Dose-dependent Effects of Smoked Cannabis on Capsaicin-induced Pain and Hyperalgesia in Healthy Volunteers. Anesthesiology. 2007 Nov;107(5):785-96.

New Study Analyzes Cost Effectiveness of Smoked Cannabis to Treat Chronic Neuropathic Pain

Kathryn Ryan, Mary Ann Liebert, Inc., January 29, 2019

Smoked cannabis as an adjunctive second-line therapy to treat chronic peripheral neuropathy can be both effective and cost-effective. The results of a new study simulating its use in one million patients are published in Cannabis and Cannabinoid Research, a peer-reviewed journal from Mary Ann Liebert, Inc., publishers. Click here to read the full-text article free on the Cannabis and Cannabinoid Research website.

In the article entitled “A Cost-Effectiveness Model for Adjunctive Smoked Cannabis in the Treatment of Chronic Neuropathic Pain,” David Grelotti, MD, University of California San Diego (La Jolla) and coauthors from UCSD, University of California Center for Medicinal Cannabis Research (San Diego), and Columbia University (New York, NY) created a computer simulation to compare the cost of usual first-, second-, and third-line care with those supplemented with smoked cannabis. They modeled efficacy and adverse events based on clinical trial and other existing study data, and derived cannabis cost from retail market pricing.

Read the full press release here


Smoking weed: When is someone too high to drive?

NBC News, January 3, 2019

It used to be the stuff of stoner comedies and “Just Say No” campaigns. Today, marijuana is becoming mainstream as voters across the country approve ballot questions for legalization or medical use.

In response, state governments are testing ways to ensure that the integration of this once-illicit substance into everyday life doesn’t create new public health risks. These efforts are sparking a difficult question: At what point is someone too high to get behind the wheel?

The answer is complicated. Brain scientists and pharmacologists don’t know how to measure if and to what extent marijuana causes impairment.

Read the rest of the story here


What’s behind the rise in cannabis-infused products?

Alex Hannaford, BBC, November 22, 2018

There’s vape oil, pain-relief cream, patches, sweets (gummy bears, sour snakes, rainbow bites – take your pick), capsules and compounds.

Cannabidiol, or CBD as it’s better known – a naturally occurring extract of the cannabis sativa plant – is now so ubiquitous in the US, you’d be forgiven for thinking there are few places it's not available and few ailments it cannot treat.

Users say they take it for everything from muscle aches and anxiety to arthritis, epilepsy and Post Traumatic Stress Disorder.

And let’s not forget Fido. There’s CBD oil for him too – with added bacon flavour.

Read the article here


Cannabis 101: A Q&A with UC San Diego Health’s cannabis experts

Gabrielle Johnston, MPH, UC San Diego Health, October 30, 2018

It seems like everywhere you turn cannabis or cannabis derivatives can be found. From ingredients in coffee and smoothies to being marketed as medicine, a cannabis craze seems to be sweeping the country. Since 2000, UC San Diego School of Medicine’s Center for Medicinal Cannabis Research and its affiliated researchers have been studying marijuana and its derivatives, their effects on mind and body and their therapeutic potential.

We asked experts to cut through the hyperbole and haze to answer some burning questions.

Read the Q&A here


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