Figure 4. Interactions in the Opioid Pathway.

A variety of pain pathways intersect with the opioid pain pathway. While this figure is not necessarily comprehensive, these “intersections” represent important research targets. For example, histamine agonists have been shown to increase the efficacy of opioid analgesics. Could histamine agonists and opioids be combined into an analgesic with increased efficacy? One downside of opioids includes the potential for significant side effects, including addiction. For pathways that intersect in the processes of side effects, can these pathways be used to alleviate side effects or decrease the chances of addiction? Interactions between pain pathways, particularly the opioid pathway, represent an important area for providing clinical pain relief to patients that are experiencing significant pain with lower risk of adverse outcomes.