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Cannabis and the Treatment of
Neuropathic Pain
Barth Wilsey MD
VANCHCS Pain Clinic
Department of Physical Medicine and Rehabilitation
UC Davis Medical Center
Disclosure
I have no relevant financial interest/arrangement
or affiliation with any organizations related to
commercial products or services to be discussed at
this program
Educational Objectives
 To
describe the history of medical marijuana in the US from the
19th Century to present day
 To recognize partial legalization versus full legalization of
marijuana
 To understand the contributions of the UC Center for Medicinal
Cannabis Research (CMCR)
 To discuss opportunities for research
• Listed in U.S
Pharmacopeia
1850-1941
– marijuana &
hashish extracts
were the 1st, 2nd, or
3rd most prescribed
meds in the US
from 1842-1890s
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neuralgia
gout
rheumatism
tetanus
hydrophobia
epidemic cholera
convulsions
chorea
hysteria
mental depression
delirium tremens
insanity
uterine hemorrhage
Prohibition
1937
California's Proposition 215
1996
• First statewide medical marijuana ballot initiative
to pass in the USA
– allow possession and cultivation of cannabis for
‘debilitating’ medical conditions if
recommended by a physician
• provide a defense against prosecution under state
criminal laws
Who are medical marijuana
patients?
• patient survey
– pain, insomnia, and anxiety
• Reinarman C, Nunberg H, Lanthier F, Heddleston T. Who are medical marijuana
patients? Population characteristics from nine California assessment clinics. J
Psychoactive Drugs. 2011;43:128-135
• physician survey
– 94% of patients receiving medical marijuana
have chronic pain, and 17% have muscle
spasms
• Kondrad E, Reid A. Colorado family physicians' attitudes toward medical marijuana. J
Am Board Fam Med. 2013;26:52-60.
Legal Marijuana, Coming to a
Vending Machine Near You
Colorado
– requires the legislature to address
• product labeling
• security requirements for wholesale and retail marijuana
establishments
• workplace drug policies
• marijuana impairment while driving
• integrating the existing medical marijuana system into the
new commercial market
• 15 percent excise tax on wholesale marijuana sales
Washington
• State Liquor Control Board given the
assignment for devising a system
• licensing
• regulating
• taxing marijuana growers, processors and retail stores
US Attorney General Response
• Prevent:
– distribution of cannabis to minors
– revenue from going to criminal enterprises, gangs, and cartels
– diversion of cannabis from states where it is legal under state law
to other states
– use as a cover or pretext for the trafficking of other illegal drugs or
other illegal activity
– violence and the use of firearms in the cultivation and distribution
of cannabis
– drugged driving and the exacerbation of other adverse public
health consequences associated with cannabis use
– growing of cannabis on public lands
– cannabis possession or use on federal property
Cole, J. Guidance Regarding Cannabis Enforcement August 29, 2013, Deputy Attorney General.
http://www.justice.gov/iso/opa/resources/3052013829132756857467.pdf
Educational Objectives
 To
describe the history of medical marijuana in the US from the
19th Century to present day
 To recognize partial legalization versus full legalization of
marijuana
 To understand the contributions of the UC Center for Medicinal
Cannabis Research (CMCR)
 To discuss opportunities for research
Full vs Partial Legalization
• full legalization has the potential to substitute
underground economies with legitimate
businesses
• pharmaceutical companies
• agribusiness
Full vs Partial Legalization
• alternatives to full legalization
• in the Netherlands, the use and sale of small quantities is
permitted while production and wholesale distribution is
banned
• penalties for possession of small amounts of marijuana could
be reduced and treated as civil rather than a criminal matter
(so-called “decriminalization”)
• production, sale, and use could be permitted but only for
medical purposes
Medical Marijuana Laws Get
Tougher
Illinois Proposed Medical
Marijuana Bill
cancer; glaucoma; HIV/AIDS; hepatitis C; amyotrophic lateral
sclerosis (ALS); Crohn's disease; agitation of Alzheimer's disease;
cachexia/wasting syndrome; muscular dystrophy; severe
fibromyalgia; spinal cord disease, including but not limited to
arachnoiditis; Tarlov cysts; hydromyelia; syringomyelia; spinal
cord injury; traumatic brain injury and post-concussion syndrome;
multiple sclerosis; Arnold Chiari malformation and Syringomyelia;
Spinocerebellar Ataxia (SCA); Parkinson’s disease; Tourette’s
syndrome; Myoclonus; Dystonia; Reflex Sympathetic Dystrophy
(RSD); Causalgia; Neurofibromatosis; Chronic Inflammatory
Demyelinating Polyneuropathy; Sjogren’s syndrome; Lupus;
Interstitial Cystitis; Myasthenia Gravis; Hydrocephalus; nail patella
syndrome; or the treatment of these conditions
Educational Objectives
 To
describe the history of medical marijuana in the US from the
19th Century to present day
 To recognize partial legalization versus full legalization of
marijuana
 To understand the contributions of the UC Center for Medicinal
Cannabis Research (CMCR)
 To discuss opportunities for research
California State Legislature
Medical Marijuana Research Act
SB847 Senator John Vasconcellos
1999
Approval Process
1997 NIH Workshop
• Department of Health and Human Services (HHS)
• DEA
– Schedule I License
• FDA
– Investigational New Drug Application
• NIDA
– supplies marijuana grown at University of Mississippi
• Research Advisory Panel of California
CMCR
Neuropathic Pain Studies
• results have been convergent
– five studies demonstrated a significant decrease
in pain after cannabis administration
• the magnitude of effect in these studies, expressed
as the number of patients needed to treat to produce
one positive outcome, was comparable to current
therapies
Educational Objectives
 To
describe the history of medical marijuana in the US from the
19th Century to present day
 To recognize partial legalization versus full legalization of
marijuana
 To understand the contributions of the UC Center for Medicinal
Cannabis Research (CMCR)
 To discuss opportunities for research
Limited Scientific Studies
• As the legal landscape evolves, the medical
one remains confusing
– fewer than 20 randomized, controlled clinical trials of
smoked marijuana for all possible uses
• these involved around relatively few people in all—
well short of the evidence typically required for a
pharmaceutical to be marketed in the U.S.
Federal Restrictions on
Cannabis Research
• Schedule I Controlled Substance
• high potential for abuse
• no currently accepted medical use in
treatment
• lack of accepted safety under medical
supervision
• use and possession is a federal offense
National Institute of Drug Abuse
(NIDA) Supplies Researchgrade Cannabis
• NIDA does not stock purified (a.k.a., Good
Manufacturing Practice grade) Δ9-THC or CBD in their
drug supply inventory for use in clinical trials
– not the case with other Schedule I drugs like heroin,
LSD, and MDMA
» which are provided legally by “private U.S laboratories”
or easily imported from abroad with federal permission,
making marijuana the only Schedule I drug with a single
federal provider
Call for Additional Studies
• 1997: National Institutes of Health
– Workshop on the Medical Utility of Marijuana
• 1999: Institute of Medicine
– Marijuana and Medicine: Assessing the Science
Base
Call for Additional Studies
• American College of Physicians
– 2008 Position Paper: Supporting Research Into
The Therapeutic Role Of Marijuana
• trod a middle ground between praising and
demonizing cannabis
– stating it is “neither devoid of potentially harmful effects
nor universally effective”
– called for “sound scientific study” and “dispassionate
scientific analysis” to find the appropriate balance
The Medical Letter
Volume 52 (Issue 1330)
January 25, 2010
• medical marijuana may be effective for treatment
of nausea, anorexia, pain and some other
conditions
– but published data supporting its efficacy for treating
patients with intractable cancer pain are limited
– dosage is not well standardized
– cannabis is often poorly tolerated, especially by older
patients
The Harvard Mental Health
Letter
Volume 26 Number 10 April 2010
• more is known about the psychiatric risks than the
benefits
– there is not enough evidence to recommend medical
marijuana as a treatment for any psychiatric disorder
– the psychiatric risks are well documented, and include
addiction, anxiety, and psychosis
Call for Additional Studies
• American Medical Association
– 2009 House of Delegates Report
• supported review of marijuana's Schedule I status
– urged an evidence-based review of marijuana's status as a
Schedule I controlled substance to determine whether it
should be reclassified to a different schedule
– NIH support of clinical studies on the utility of medical
marijuana
NIH Sponsored Studies
THC / Dronabinol / Marinol
Efficacy Trial of Oral Tetrahydrocannabinol in Patients With
Fibromyalgia at Hadassah Medical Organization, Jerusalem, Israel
Nabilone / Cesamet
Efficacy and Safety Evaluation of Nabilone as Adjunctive Therapy to
Gabapentin for the Management of Neuropathic Pain in Multiple
Sclerosis at University of Manitoba, Winnipeg, Canada
Nabiximols / Sativex
A Study of Sativex® for Relieving Persistent Pain in Patients With
Advanced Cancer in the United States, the UK and Germany
NIH Sponsored Studies
Cannabidiol (CBD)
Cannabidiol for Inflammatory Bowel Disease at Meir Medical Center,
Kefar Saba, Israel
Smoked / Inhaled Cannabis
Comparing the Effects of Smoked and Oral Marijuana in Individuals
With HIV/AIDS at New York State Psychiatric Institute, USA.
Effects of Vaporized Marijuana on Neuropathic Pain in Spinal Cord
Injury at CTSC Clinical Research Center, Sacramento, United States.