New pharmacological strategies for pain treatment: cannabinoids under examination

Abstract

 Pain is an unpleasant sensory or emotional experience that is associated with ongoing or potential tissue damage and it can be classified by its origin (nociceptive, neuropathic), severity (mild, severe) or duration (acute, chronic). In general, commercially available drugs for pain relief are effective, but their long-term use can lead to several problems. For example, although opioids are very strong analgesics their efficacy can decrease when chronically used and safety problems can appear. According to statistics, 15% of the population suffers from chronic pain. Chronic pain is a disabling state, which can be difficult to treat. Thus, the finding of new analgesic drugs and research into new targets and strategies is essential. One of the systems that is currently under investigation is the endocannabinoid system. Endogenous cannabinoids are synthesized in the human body and they regulate several physiological processes (e.g. pain) through activation of cannabinoid receptors. Cannabinoids are present in the Cannabis plant and induce analgesia by regulating the endogenous cannabinoid system. Unfortunately, some of the cannabinoids are psychoactive, which is a feature that limits their therapeutic use. In recent years, research into non-psychoactive cannabinoids has increased and they have been tested in several clinical trials together with psychoactive cannabinoids. Finally, in an attempt to improve the efficacy/safety ratio, a combination of opioids and cannabinoids are being studied with the objective of achieving synergistic analgesic effects and decreasing side effects. Overall, research into cannabinoids has opened up new ways for finding better pharmacological strategies for pain treatment.