Emeritus Professor Laurence Mather

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Emeritus Professor Laurence Mather
Medicinal cannabis
7th Annual ACT ATOD Conference
24 September 2014
National Portrait Gallery
Emeritus Professor Laurie Mather
[email protected]
Topics
• What are the medical benefits of
crude cannabis? What about
pharmaceutical cannabis?
• For whom, when and how?
• Why hasn’t this area of medicine
been developed further?
Cannabis is…
a demon weed –
it does untold harm,
especially to our youth
a beneficent herb –
it helps you relax, and
is less harmful than
alcohol and tobacco
a wonder drug –
it assists in
managing serious
medical conditions
like no other
Cannabis is…
• One of many surviving ancient plants: used
for folk medicine, fibre-making, nutrition, and
enhancing spiritual and social experiences
• Cannabis sativa – ‘hemp plant’
• Cannabis Indica – ‘medicine plant’
• Adopted into Western societies mid 19th C
• ‘Marijuana’ (‘marihuana’): recreational drug
of 1920s Mexican American workers
• US-led international treaties: illegal status in
many countries including Australia
The Demon (or Demonised) Weed…
Harry J Anslinger, Commissioner,
US Bureau of Narcotics 1930-1962
• "How many murders, suicides, robberies,
criminal assaults, holdups, burglaries and
deeds of maniacal insanity it causes each
year, especially among the young, can
only be conjectured...”
• “No one knows, when he places a
marijuana cigarette to his lips, whether he
will become a joyous reveller in a musical
heaven, a mad insensate, a calm
philosopher, or a murderer..."
Historically: benefits
Dr WB O’Shaughnessy
(India, 1847) –
‘to relieve pain, muscle
spasm, convulsions of
tetanus, rabies,
rheumatism and epilepsy’
Sir John Russell Reynolds, Queen Victoria’s
physician (1890) – “Indian hemp…is one of
the most valuable medicines we possess”
Historically: harms
Indian Hemp Drugs
Commission Report
(1894) (7 vols, 3,281
pages): “The moderate
use practically produces
no ill effects”
AMA (1937): “...positively no evidence to
indicate the abuse of cannabis as a
medicinal agent or ... cannabis addiction”
“Crude cannabis”
• Plant produces 400+ recognized
chemicals, incl. ~100 cannabinoids,
e.g. ∆9-THC, CBD, CBN in variable
mixture (±contaminants)
• Cannabis hybrids ~800 strains
• Strains / processing / home growing →
?chemical consistency
• ‘Entourage effect’ of other chemicals
• User variables e.g. method of use
“Pharmaceutical cannabis”
• Pure chemical entity (biosynthetic or
synthetic) in final dose form
• e.g. oral capsule, dronabinol (Marinol) synthetic THC
• Botanical or plant extract in final dose form
• e.g. Sativex (mouth spray with 2.7mg THC + 2.5mg
CBD per 0.1 mL spray)
• Processed crude plant product: patientready for use as cannabis ‘tea’ or by
vaporisation ±different THC:CBD ratios
• e.g. Dutch Office of Medicinal Cannabis: “Bedrocan”,
“Bedrobinol”, “Bediol” and “Bedica”
For whom?
Grotenhermen F, Muller-Vahl K. [Therapeutic
potential of cannabis and cannabinoids. Dtsch Artzbl
Int 2012;109:495-501]
Reviewed EVIDENCE from controlled trials for
patients needing…
• control of nausea/vomiting, esp. for cancer
chemotherapy: +40 -1
• appetite stimulation in patients with wasting
syndrome: HIV/AIDS: +7 -0; CA: +3 -1
• control of muscle spasticity, esp. MS: +9 -3
• chronic pain management: neuropathic: +12 -2;
other (CA, rheum, fibromyalgia) +11 -0
Evidence: results of treatments?
• Actions and benefits underpinned by
endocannabinoid physiology
• Variable and individual – ‘responders’ and
‘non-responders’ – not surprising
• Improvements in Activities of Daily Living –
depending on levels of disability
• Improved mood and other QoL elements
• Improvements in carer’s QoL e.g. sleep
• Reduction in use of other health care
• Reductions in more harmful drugs, incl.
reduction in opioid-related deaths
Emerging evidence: benefits?
PRESENT – a useful ‘second line’ medicine
• to relieve distressing symptoms when the
conventional medicines have been ineffective
or have unacceptable side effects
• not just for patients with ‘terminal illness’
FUTURE – uses may expand
• possibilities currently under research
(e.g. childhood Dravet syndrome, anti-cancer;
post-traumatic stress management)
• other medical applications not yet reported in
the literature
Evidence: risks?
• ACUTE learning and memory and
cognitive impairments, sleepiness,
tachycardia, euphoria or dysphoria
(circumstantial and conditional)
• CHRONIC risk of dependence,
personality disorders, schizophrenia,
etc.
• RISKS inappropriately extrapolated
from ‘recreational’ use to medical use
Used how and when?
• Oral ingestion
•
•
•
•
•
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• Oral inhalation
tincture
capsules/pills
herbal tea
oil, butter
baked ‘cookies’ •
sublingual /
oromucosal spray
• cigarettes – and
smoked variants
• vaporisers and
aerosol variants
Patient controlled
analgesia paradigm
– rapid feedback
from dose to effect
Why hasn’t this area of medicine been
developed further?
THE THREE FEARS
1. POLITICAL FEAR - Fear of looking ‘soft
on drugs’, elector backlash, sending ‘the
wrong message’
2. PHARMACOLOGICAL FEAR - Fear of
drug-caused ‘things’ that we don’t know
about
3. BUSINESS FEAR - Fear of not making
enough money
Why hasn’t this area of medicine been
developed further?
• Research issues –
• problems in securing intellectual property
rights over cannabis – a natural product:
deterrence to the pharmaceutical industry
• basic laboratory research funded;
epidemiology and harms research
favoured; clinical pharmacotherapy
research thwarted
• how to present to regulatory body (TGA)
Why hasn’t this area of medicine been
developed further?
• Societal issues –
• Stakeholders – driving forces
• Public opinion – already shifted in favour
• Medical issues – establishment conservatism
• Political issues – ideology
• lack of willingness to accept evidence or will to
change ideology ± inertia and/or antagonism (e.g.
NSW Inquiries 2000 and 2013)
• National approach – necessary
• “We need more research…”
Topics
• What are the medical benefits of
crude cannabis? What about
pharmaceutical cannabis?
• For whom, when and how?
• Why hasn’t this area of medicine
been developed further?