Cannabis and Pain

This editorial is occasioned by the publication in Pain Medicine of two quite distinct articles [1,2] on the topical subject of cannabis and pain. As a point of departure, it is necessary to define terms. Cannabis sativa L. is a highly variable biochemical and morphological plant frequently termed “marijuana,” an obsolete and pejorative terminology for an ancient Old World species that has been utilized as an analgesic for millennia. The cannabis of commerce is frequently divided into two categories termed “sativa” and “indica” that purport to refer to differences that are neither taxonomically nor pharmacologically defensible. Similarly, one may refer to “strains” of cannabis, a label that is properly applied to bacteria or viruses, but not plants. Rather, what is scientifically relevant is the biochemical profile of a given cannabis variety, prompting the more appropriate terminology of chemical varieties or “chemovars.” The first entry [1] documents the contents of a 2016 pain symposium encompassing contributions of several experts on pain, addiction, and drugs of abuse. Although it certainly is the case that the participants outlined at length the theoretical dangers and pitfalls of cannabis, there is little allusion to first-hand experience with cannabis as medicine, and the overall impression created may be unnecessarily alarmist and particularly attributable to a conflation of the adverse event profile of recreational smoking of cannabis as compared with its therapeutic application in chronic pain patients. A few sweeping statements are necessary as a prelude (reviewed in [3,4]). Cannabis is unimpressive as an analgesic for acute pain, with the possible exceptions of treatment of paroxysmal or breakthrough pain or its adjunctive utilization in conjunction with opioids [5]. Rather, the benefit of cannabis in pain management is most apparent in patients with chronic conditions, particularly in those with neuropathic pain wherein opioids are suboptimally effective, or may even exacerbate the condition. Second, therapeutic use of cannabis is different in its aim and methods in comparison to recreational usage, wherein the entire point is to create a “high” or intoxication that must be considered a side effect in pain treatment, wherein the ideal result would be effective analgesia without alteration of consciousness or impairment. This seeming discrepancy is logically supported by the differences in methodology of dosing. Recreational cannabis is far and away linked to inhalation, usually by smoking, a technique that will never garner support in the medical or regulatory communities. After inhalation, a rapid pharmacokinetic peak activity is attained, but at the risk of intoxication, and the need for frequent redosing risks the production of reinforcement and dependency. The frequency of cannabis dependence is frequently cited based on US data as 9%, a figure that must be challenged and downgraded by up to 60% due to the fact that an equivalent number of cannabis users are placed in treatment for cannabis addiction through the legal system as an alternative to incarceration, irrespective of whether true dependency is operative in a given individual. The addiction risk of therapeutic cannabis usage, in contrast, approaches 0% in formal studies, particularly in that no mortality, serious sequelae, tolerance, dose escalation, or withdrawal has been documented [3]. Risks can be further reduced through utilization of proper extracts, particularly those containing cannabidiol (CBD), which counteracts the anxiety, tachycardia, dependency, and other potential pitfalls of excessive tetrahydrocannabinol (THC) exposure.