Page 2 - Top Ten Tips Palliative Care Clinicians Should Know About Medical Cannabis

2 BRISCOE ET AL.

on the top 10 tips to familiarize PC clinicians with this rapidly psychiatric side effects; therefore, screening for psychologi-
evolving space. cal conditions such as depression, anxiety, and a history of
psychosis is also indicated. Studies have not supported the
Tip 1: Local Laws and Regulations Vary Regarding use of cannabis in treating depression and, furthermore, use
Medical Cannabis of cannabis in the context of cannabis use disorder (vs.
medical cannabis use, about which we have less evidence) is
It remains a federal crime to sell or transport cannabis
because it is a Schedule I substance. Nevertheless, 33 states, associated with other psychiatric conditions such as depres-
9,14
in addition to the District of Columbia, Guam, and Puerto sion. Therefore, cannabis use should be investigated be-
Rico, have legalized medical cannabis and 10 of those have fore the prescription of opioids or certifying of a qualifying
condition for medical cannabis.
legalized recreational cannabis as well. 2,6 The National Medical cannabis use (or illicit cannabis use for self-
Conference of State Legislatures regularly updates a map treatment purposes) presents a challenge for concomitant
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delineating medical cannabis laws. Notably, clinicians and opioid prescribing. When clinicians discover, either through
pharmacies within the Veterans Affairs health system cannot history or drug testing, that a patient is using cannabis, they
recommend or dispense medical cannabis since federal law should explore the reasons for use and probe for use of other
overrides any state regulation. However, veterans will not illicit substances. True to the ‘‘gateway drug’’ paradigm, il-
lose Veterans Administration (VA) access or benefits be- licit cannabis use is associated with illicit use of other sub-
Downloaded by Gothenburg University Library from www.liebertpub.com at 01/15/19. For personal use only.
cause they participate in a state-level medical cannabis pro- stances, which may cause more serious adverse interactions
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gram. Regulation varies from state to state as to how much with opioids. 15 Such illicit use may also place opioids in the
medical cannabis patients may possess and how it can be hands of those individuals who can divert them (or associate
obtained (e.g., personally grown vs. obtained from a dis- with those likely to steal and divert them) and cause patient
pensary). Patients should exercise caution when purchasing and societal harm. Physiologically, although concomitant use
cannabis online as there may be less oversight resulting in of medical cannabis use has been associated with a syner-
potentially diminished purity. 8
gistic effect on analgesia without altering opioid levels, such
Regulations also vary regarding clinicians’ involvement in
evidence must be applied with caution as the psychoactive
how patients obtain medical cannabis. Unlike other sub- 16
effects, particularly sedation, may also be synergistic.
stances obtained with a clinician’s approval, medical can-
Therefore, a urine drug screen that is unexpectedly positive
nabis is usually not prescribed. Rather, an appropriate
for THC should prompt a conversation by clinicians about
clinician must certify that a patient has a qualifying condition
before the patient can obtain medical cannabis from a dis- these concerns.
pensary. Qualifying conditions vary by state and range from
pain to nausea to cancer. Unfortunately, patients are some- Tip 3: Medical Cannabis May Be Useful
times left to experiment with dose and route of administra- for the Treatment of Neuropathic Pain
tion, relying on recommendations from friends, media, the Current evidence suggests that cannabis can provide
dispensary, and sometimes the clinician who certified their modest relief of pain resulting from various etiologies in
qualifying condition. broad populations of patients. 6,9,12 Most notably, among the
various types and etiologies of pain, evidence is growing that
Tip 2: A Comprehensive Pain Assessment Includes medical cannabis is particularly effective in the management
Asking About Cannabis Use of various types of neuropathic pain (e.g., diabetic, traumatic,
HIV, and chemotherapy). 17–21 There is also evidence that
One of the indications for medical cannabis with the most
6,9 synthetic cannabinoids, such as dronabinol 2.5–10 mg or na-
evidence is controlling pain. At least part of the impetus for 22
bilone 1–4 mg daily, can treat neuropathic pain. Evidence
the scientific study of cannabis has been the use of illicit
cannabis to improve pain, which for the majority of users is also supports the use of medical cannabis in relieving cancer-
effective. 10 Cannabinoid receptors are present in afferent related pain, although the quantity of studies is smaller when
23
nerves that respond to painful stimuli and are also found in compared with those focused on neuropathic pain.
parts of the brain associated with analgesia (e.g., periaque- The majority of these studies used inhaled cannabis at
ductal gray, raphe nuclei, and central-medial thalamic nu- various doses and frequencies, and the ratio of THC to CBD
clei), suggesting a possible therapeutic role in pain in any given preparation may vary as well. This limits gen-
eralizability and confounds the anticipatory guidance clini-
management, both synergistically with the opioid system and cians may give their patients as there is no ‘‘standard’’ dose,
independent of it. 11,12 route of administration, or formulation of medical cannabis
Patients may have experiences using variable amounts and for these applications. Finally, the results of these clinical
routes of administration of cannabis in an attempt to treat studies cannot be extrapolated patients who use illicitly
their own pain. They may also have had particular adverse procured cannabis for the purposes of pain management.
effects to the recreational use of cannabis (e.g., paranoia, dry
mouth, and sedation) that may inform plans regarding the use Tip 4: Medical Cannabis Can Be Used to Treat
of medical cannabis. Clinicians who practice in states where Chemotherapy-Induced Nausea and Vomiting
medical cannabis is legal should be particularly attuned to
this as nonmedical use of cannabis increases when medical Chemotherapy-induced nausea and vomiting (CINV) used
cannabis is legalized. 13 Because pain in PC settings is often to be a disabling, sometimes treatment-limiting, side effect
managed with opioids, a comprehensive pain assessment that has since been relieved significantly by the use of modern
must include investigation of nonmedical and medical uses of antiemetic regimens. Nevertheless, medications such as on-
cannabis as well as other substances. Cannabis has neuro- dansetron, aprepitant, and others have their own side effects.