New therapies to relieve pain: The search for more efficient and safer alternatives to opioid pain killers.

Abstract

EMBO Reports (2018) e46925 Opioids are a largely efficient medication for relieving severe pain and are prescribed for a wide variety of indications including metastatic cancer, arthritis, neuropathy or post‐surgical pain. These drugs target opioid receptors to produce effects similar to morphine and include moderately strong painkillers such as oxycodone and hydrocodone (Vicodin), and strong drugs like fentanyl, which resembles opium‐derived morphine and heroin. The great efficiency of opioids in treating severe pain has also been the major drawback for longer‐term use given their addictive power. This does not matter for short‐term use, for instance to ease post‐operative pain, or terminal cancer when the primary requirement is to relieve suffering. Yet, the addictive side effect has become a huge societal problem; in addition, opioids do not work against all types of chronic pain, including some of the most severe cases such as cancer‐induced bone pain or some cases of neuropathy resulting from nerve damage. These problems have spurred efforts to develop new drugs for treating pain with some success in developing derivatives with reduced side effects. The other major avenue of research is the identification of relevant pain pathways or protein binding sites including those involved in the placebo effect. Their efficiency has spurred physicians to prescribe opioids too readily, while drug companies have heavily advertised their effects and understated the side effects to boost usage. This three‐way collusion between patients, doctors and pharmaceutical companies has stoked the ongoing epidemic of opioid addiction that has afflicted the USA and Canada in particular, but also other developed countries in Europe and Asia. Apart from exacting a heavy social toll through loss of motivation or loss of jobs, impact on relationships, crime and so on, opioid addiction has dangerous physiological effects, notably on the respiratory system, which causes most of the overdose …