Cannabinergic Pain Medicine

Abstract

This article attempts to cover pragmatic clinical considerations involved in the use of cannabinergic medicines in pain practice, including geographical and historical considerations, pharmacokinetics, pharmacodynamics, adverse effects, drug interactions, indications, and contraindications. Topics include molecular considerations such as the 10-fold greater abundance of cannabinoid type 1 receptors compared to µ-opioid receptors in the central nervous system and anatomic distributions of cannabinoid receptors in pain circuits. The article uses a narrative review methodology drawing from authoritative textbooks and journals of cannabinoid medicine, Food and Drug Administration-approved cannabinoid drug labels, and current and historical pain medicine literature to address core clinical considerations. To survey the current evidence base for pain management with cannabinergic medicines, a targeted PubMed search was performed to survey the percentage of positive and negative published randomized-controlled trial (RCT) results with this class of pain medicines, using appropriate search limit parameters and the keyword search string "cannabinoid OR cannabis-based AND pain." Of the 56 hits generated, 38 published RCTs met the survey criteria. Of these, 71% (27) concluded that cannabinoids had empirically demonstrable and statistically significant pain-relieving effects, whereas 29% (11) did not. Cannabis and other cannabinergic medicines' efficacies for relieving pain have been studied in RCTs, most of which have demonstrated a beneficial effect for this indication, although most trials are short-term. Adverse effects are generally nonserious and well tolerated. Incorporating cannabinergic medicine topics into pain medicine education seems warranted and continuing clinical research and empiric treatment trials are appropriate.