One of the complications I face with clinical
practice in Florida is that for the past couple of years, the state has allowed
the use of so called Medical Marijuana and Cannabis. Since the law went into
effect, dispensaries have cropped up in every city and town and I am informed
by a patient that acquiring a prescription for MM from an MD affiliated with a
dispensary is as easy as showing up and signing a few forms. None of my
patients who have been prescribed MM had a physical exam by the dispensing
physician and there is no follow up unless the patient requests one. The non
medical dispensary operators are given carte
blanche to suggest dosage and delivery mechanisms and some patients who
have expressed concerns about addiction and other negative side effects have
been told that MM “works for everyone” and that there are “absolutely no negative
side effects, ever”.
Because marijuana is currently classified by the US
federal government as Schedule I, “a drug with no medical use”, studies that
discuss medical marijuana are limited in both number and scope. Many studies
compare smoking habits and respiratory distress among cigarette and cannabis
smokers, as well as symptoms of abuse and addiction in recreational users, but
few address the side effects of medical marijuana.
One study in Canada described the most common
side effects of cannabis use in patients with non-chronic cancer pain as “cognitive side effects” and dry
mouth. In the United States, nabilone may produce similar “cognitive side effects” or psychiatric
symptoms, hypo and hypertension, and tachycardia if the prescribed dosage is
too high. Dronabinol has also been associated with a “cognitive side effects,” sleepiness, or
withdrawal symptoms lasting up to 48 hours that appeared in only one study,
which promptly stopped dispensing the medication. The categorization of
cannabis as Schedule I, therefore, is a double-edged sword: because few
clinical trials have been run, few negative side effects have been reported.
cannabis use in people with chronic non-cancer pain prescribed opioids:
findings from a 4-year prospective cohort study
~ The Lancet, British
Medical Journal, July 2018
In conclusion, cannabis use is
common in people with chronic non-cancer pain who have been prescribed opioids,
and interest in medicinal use of cannabis is increasing. We found no evidence
that cannabis use improved patient outcomes; those who used cannabis had
greater pain and lower self-efficacy in managing pain. Furthermore, we found no
evidence that cannabis use reduced pain interference or exerted an
opioid-sparing effect. ~
Do the benefits outweigh the risks?
~ Current Psychiatry ·
There is no clear and convincing
evidence MM is beneficial for psychiatric disorders, and Cannabis can
impair cognition and attention and may precipitate psychosis. The risks of
deleterious effects are greater in adolescents. Cannabis use causes impairment of
learning, memory, attention, and working memory. Adolescents are particularly
vulnerable to the effects of Cannabis on brain development at a time
when synaptic pruning and increased myelination occur. Normal brain development
could be disrupted. Some studies have linked Cannabis use to abnormalities
in the amygdala, hippocampus, frontal lobe, and cerebellum. From 1995 to
2014, the potency of Cannabis (THC concentration) increased from 4% to
12%.58 this has
substantial implications for increased abuse among adolescents and the deleterious
effects of Cannabis on the brain.
Heavy Cannabis use impairs motivation and could precipitate
psychosis in vulnerable individuals. Cannabis use may be linked to the
development of schizophrenia.59
There are no well-conducted
Randomized Controlled Trails on the efficacy of MM, and adequate safety data
are lacking. There is also lack of consensus among qualified experts. There is
soft evidence that MM may be helpful in some medical conditions, including but
not limited to CINV, neuropathic pain, epilepsy, and MS-related spasticity.
Currently, the benefits of using MM do not appear to outweigh the risks. ~
Cannabis for Chronic Pain: Not Ready for Prime Time
~ American Journal of Public Health January 2019
use of cannabis (particularly its principal psychoactive constituent, Δ tetrahydrocannabinol
or THC) is associated with health risks including lung disease (when smoked),
cardiovascular disease, acute pancreatitis, and cannabinoid hyperemesis
syndrome. Cannabis users are also at increased risk for occupational
injuries, and cannabis-associated “drugged driving”, sometimes fatal, is
increasing. Cannabis use during pregnancy has been associated with increased
neonatal morbidity or death.Finally, the myth that marijuana is non-addictive
has been dispelled by studies of forced abrupt cessation of use indicating
potential rebound hyperalgesia and craving. As the health risks associated with
cannabis come under increasing scrutiny.
of gray matter in the brain in chronic cannabis users has long been recognized.
Empirically established deficits following months to years of use involve—but
are not limited to—executive functioning, information retrieval, learning,
abstraction, motor skills, and verbal abilities, with use of higher-THC
cannabis resulting in more profound deficits. Psychopathological consequences
of cannabis use include acute psychosis, schizophrenia, worsened social
functioning in schizophrenia, bipolar disorder, depression, and anxiety
(particularly with increasingly common high-sativa content strains).
data on the efficacy of cannabis for pain management are not particularly
encouraging.Cannabis can be helpful in relieving neuropathic pain,
with the magnitude of analgesia generally contingent on the amount of THC.
Unfortunately, higher-THC cannabis, similar to opioids, also produces more
cognitive side effects, often rendering patients impaired at work and in
activities of daily living. Moreover, much of the earlier clinical trial
literature on cannabis for neuropathic pain has been rendered obsolete.
it remains extremely difficult to conduct clinically relevant medical cannabis
research in the United States because of the drug’s Schedule I status, and the
requirement that all cannabis used be obtained from a single farm at the
University of Mississippi, and it is permitted to grow only 1000 pounds of
cannabis for research purposes each year. Even more problematic is that until
very recently, the University of Mississippi was permitted to cultivate
cannabis with a maximum THC content of 7%, yet 67% of medical cannabis
consumers choose to use oils and other concentrates with THC contents as high
as 90%. Cannabis for investigation with a higher THC content (13.4%) was
obtainable only recently from the National Institute on Drug Abuse (NIDA).
Thus, research on the analgesic efficacy of what the DEA considers “strong
marijuana” has been flawed.
to these reservations concerning cannabis as an analgesic is that THC is not
the most medically relevant constituent of cannabis. Cannabidiol (CBD) is a
noneuphoriant cannabinoid with a good safety profile and has activity as both
an analgesic and anti-inflammatory. Importantly, CBD modulates the euphoria
produced by THC and provides mild anxiolysis. Although it is thought that
cannabis contained equal amounts of THC and CBD in pre-agricultural times, when
the plant grew wild, users’ and hence growers’ desire to maximize THC content
for its euphoric effects has resulted in CBD being all but bred out of the vast
majority of cultivated cannabis. Efforts to find cannabis that contains low
concentrations of THC and high levels of CBD in dispensaries are often futile. Furthermore,
the CBD that is found in common hemp (the most widely used source for commercial
non medical CBD oil) is virtually nonexistent.
if any health care providers who authorize medical cannabis educate their
patients specifically to seek the most “medicinal” forms of the drug. Even if
this aspect of sourcing a uniform, well-characterized supply of cannabis for
research or clinical purposes were overcome, another fundamental challenge for
such studies is that (unlike for morphine or other opioids) blood levels of
these agents do not consistently correlate with their in vivo effects. ~
In the last Blog we learned that traditional
Chinese medicine and Chinese medical psychiatry do not condone the use of the use of medical
cannabis or marijuana for indications of pain management, addiction withdrawal,
constipation and lack of appetite does not advise its use given the historical
understanding and the negative side effects involved.
In the light of the unsettling safety profile of cannabis, the lack of strong empirical support for its efficacy, the general absence of CBD in what is used “medically,” and the methodological challenges in conducting research suggest that, at present, cannabis should not necessarily be considered an optimal choice as a drug for pain management.
Yours in good health,