Page 4 - Top Ten Tips Palliative Care Clinicians Should Know About Medical Cannabis

4 BRISCOE ET AL.

anorexia and cachexia. Inhaled cannabis has also been shown use of cannabis and synthetic cannabinoids (including dro-
to be effective in weight gain in HIV/AIDS. 6 nabinol) and may occur with other forms of medical cannabis
These improvements in anorexia and weight loss in HIV/ as well. 6,47,48 This reinforces the need for good clinical
AIDS have led researchers to investigate whether similar practice in monitoring for adverse effects of those substances
benefits can be seen in other conditions such as cancer. Un- a patient is ingesting.
fortunately, evidence has revealed that medical cannabis is
not effective for the treatment of cancer-associated anorexia Tip 9: Pediatric Epilepsy Is a New and Growing
and cachexia. 6,36 This may be due to the pathophysiology of Indication for Medical Cannabis
the anorexia itself, with the high metabolic rate of the cancer As cannabinoids are effective in preventing seizures in
contributing at least in part to the overall weight loss of those
animal models, there is hope they may have clinical appli-
patients. Furthermore, depending on the route of adminis- 49
cations for humans in epilepsy. Furthermore, some people
tration, medical cannabis may have side effects that further
who use cannabis illicitly find that it helps their seizures,
impair a patient’s willingness to eat and enjoyment of eating
although there are cases of its effectiveness even with non-
(e.g., dry mouth). Given this evidence, we cannot recommend
therapeutically low doses, suggesting that some data may be
cannabinoids for the improvement of cancer-associated ca- 50
contaminated with nonepileptic seizures. The two system-
chexia and anorexia.
atic reviews to date have not supported the use of medical
51
cannabis for the treatment of seizures. Evidence is growing
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Tip 8: Smoking Medical Cannabis Is Not Associated for the use of medical cannabis in treating seizures, particu-
with Lung Cancer or Chronic Lung Disease, But Does larly in children, and sometimes in refractory cases. CBD
Cause Side Effects specifically may be useful in the management of seizures in
those children with Dravet syndrome or Lennox–Gastaut
Since both tobacco and cannabis can both be smoked, there 52,53
was initially concern that cannabis, when smoked, could also syndrome at doses as high as 25–50 mg/kg per day. Gi-
ven this evidence in both these syndromes, the FDA recently
be associated with lung cancer and chronic lung disease. approved Epidiolex oral solution in these clinical situa-
There are substantial differences in use between the two tions. 54 The initial dose is 2.5 mg/kg twice daily by mouth
substances. For example, tobacco cigarettes are usually and increased to a maintenance dose of 10 mg/kg twice daily.
smoked in much greater quantity than cannabis cigarettes. As CBD inhibits CYP3A and CYP2C, which are respon-
Perhaps for this reason, there is no convincing evidence that sible for the metabolism of several antiepileptic drugs, cli-
the use of medical cannabis is linked with lung, head and nicians should monitor for toxicity of other drugs if a child is
neck, or esophageal cancers. 6,37,38 There is, however, a link concomitantly taking CBD. 55 The long-term effects of
between chronic and frequent use of cannabis and the de- medical cannabis on brain development in children have not
velopment of testicular cancer, particularly nonseminomas. 39 been established. As is the consistent theme across trials
Although there is no convincing evidence that cannabis use examining the therapeutic applications of medical cannabis,
leads to chronic obstructive pulmonary disease, there is a link the ratio of THC to CBD and other cannabinoids that pro-
between smoking cannabis and cough and bronchitis, which vides the most therapeutic benefit in epilepsy has yet to be
may be related to the irritating smoke itself rather than any
active ingredient. 40 These effects make smoking a less ap- discerned.
pealing route of administration for those with chronic lung
Tip 10: Cannabis Use Is Associated with an Increased
disease.
Risk of Motor Vehicle Collision, and This Link Can
The most common adverse effects from medical cannabis,
Likely Be Extrapolated to Medical Cannabis
as opposed to recreational cannabis, include dizziness, dry
mouth, nausea, euphoria, confusion, somnolence, and hallu- Although there is no evidence to support that cannabis can
cinations. 9,35 Those with preexisting cardiovascular disease be lethal in overdose, driving while under the influence of
may be at increased risk of myocardial infarction from cannabis is associated with a 20%–30% higher odds of a
medical cannabis use, which is important to consider when motor vehicle collision (MVC). 56 Some studies that have
treating older adults. 41,42 Most impressively, nausea, vomit- investigated this relationship identified those people who
ing, and abdominal pain, a triad called ‘‘cannabinoid hyper- were reportedly driving under the intoxication of cannabis as
emesis syndrome,’’ can result from chronic and frequent use actually driving with a recent or prior history of using can-
of cannabis. This syndrome may be less of a risk when can- nabis but without acute intoxication. No studies have inves-
nabis is used in an appropriate medical context. 43 tigated the relationship between medical cannabis use
Cannabis is abused for its neuropsychiatric effects, and specifically and MVC. However, medical cannabis does have
these may be prominent with medical use as well. Diagnosing neuropsychiatric side effects that could impair driving, in-
primary psychiatric disorders can be challenging when pa- cluding impaired attention, dizziness, confusion, and som-
tients are using cannabis (either for recreational or medical nolence. 9,46,57 Given that time to peak effect can vary
use). Cannabis has been associated with depression and depending on the route of administration and the particular
anxiety, although the evidence has not yet established a di- composition of cannabinoids, it is difficult to make a general
rectional link: Are depressed or anxious patients more likely recommendation as to how long after taking medical can-
to use cannabis, or are those people who use cannabis more nabis patients should avoid using heavy machinery or driv-
likely to become anxious or depressed? 6,44 Cannabis’s link ing, but certainly a period of at least several hours.
with suicide is similarly unclear. 45 Medical cannabis can Definitions of impairment while driving vary from state to
impair memory and attention as well as cause confusion and state and, therefore, specific recommendations about what
46
somnolence. Psychosis is a well-known risk of recreational might legally constitute ‘‘impairment’’ cannot be made in